Luan Van Giang Full 2521

8/12/2019 Luan Van Giang Full 2521

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LUN VN THC S CAO HC

Nghin cu iu ch vt liu TiO2 bin tnh kch thchnano mt v kh nng quang xc tc ca chng


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Lun vn thc skhoa hc Nguyn ThKim Giang-K18

Nghin cu iu chvt liu TiO2bin tnh kch thc nano mt v kho st khnngquang xc tc ca chng

- 1 -

MU

Vt liu nano l mt trong nhng lnh vc nghin cu nh cao si ng nht

trong thi gian gn y. iu c thhin qua s cc cng trnh nghin cu

khoa hc, scc bng pht minh sng ch, s cc cng ty c lin quan n khoa

hc, cng nghnano gia tng theo cp sm. y l mt lnh vc ht sc mi m

v n bin gii gia phm vi ng dng ca thuyt lng thin i v thuyt vt

l cin. Sdcng nghnano iu chcc vt liu mi ang rt c quan tm

l do hiu ng thu nh kch thc lm xut hin nhiu tnh cht mi c bit v

nng cao cc tnh cht vn c ln so vi vt liu khi thng thng, c bit l cc

hiu ng quang lng tv in t. Vt liu nano kch cnano mt c nhng tnh

cht u vit nhbn chc cao, tnh bn dn, cc tnh cht in quang ni tri,

hot tnh xc tc cao, v.v [1].

Titan ioxit (TiO2) l mt trong nhng vt liu cbn trong ngnh cng ngh

ny bi n c cc tnh cht l ha, quang in tkh c bit v c bn cao, thn

thin vi mi trng. V vy, titan ioxit c rt nhiu ng dng trong cuc sng nh

ha mphm, cht mu, sn, chto cc loi thy tinh, men v gm chu nhit dng ht mn kch thc nano mt TiO2c nhiu ng dng hn trong cc lnh vc

nhchto pin mt tri, sensor, ng dng lm cht quang xc tc xl mi trng,

chto vt liu tlm sch [2-4].

c bit TiO2c quan tm trong lnh vc lm xc tc quang ha phn hy

cc cht hu cv xl mi trng. Tuy nhin, hiu sut ca qu trnh quang xc

tc ny i khi bngn cn bi rng vng cm ca n. Vng cm ca TiO2nm

gia vng tngoi (UV) (3.0 eV i vi pha rutile v 3.2 eV i vi pha anatase),

m vng UV chchim mt phn nhca nng lng mt tri (~ 4%) [35].

Do d, mt trong nhng mc ch khi ci tin hiu sut qu trnh quang xc

tc ca TiO2 l lm tng hot tnh quang xc tc bng cch dch chuyn rng

vng cm tvng UV ti vng khkin. lm c iu ny cc nh nghin cu

tin hnh bin tnh vt liu TiO2 bng nhiu phng php khc nhau nha


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- 2 -

thm cc kim loi, oxit kim loi ca cc nguyn tkhc nhau vo trong mng tinh

thTiO2nhZn, Fe, Cr, Eu, Y, Ag, Nihoc a thm cc phi kim nhN, C, S, F,

Cl hoc ng thi a hn hp cc nguyn tvo mng tinh thTiO2 Hu ht

nhng sn phm c bin tnh c hot tnh xc tc cao hn so vi TiO2ban u

trong vng nh sng nhn thy [35].

Tnhng nghin cu nn tng , vi mong mun c ng gp mt phn

nhcho spht trin ca ngnh vt liu mi, tc gi nghin cu ti:

Nghin cu iu ch vt liu TiO2 bin tnh kch thc nano mt v

kho st khnng quang xc tc ca chng.


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- 3 -

PHN I: TNG QUAN

1.1. GII THIU VTITAN IXIT KCH THC NANO MT

1.1.1. Cu trc ca titan ioxit [1], [6]

Titan ioxit l cht rn mu trng, khi un nng c mu vng, khi lm lnh th

trli mu trng. Tinh thTiO2c cng cao, kh nng chy (tnc0= 18700C).

a. Cc dng th hnh ca titan ioxit

TiO2c bn dng th hnh. Ngoi dng v nh hnh, n c ba dng tinh thl

anatase (tetragonal), rutile (tetragonal) v brookite (orthorhombic) (Hnh 1).

Rutile l dng bn phbin nht ca TiO2, c mng li tphng trong

mi ion Ti4+c ion O2-bao quanh kiu bt din, y l kin trc in hnh ca

hp cht c cng thc MX2, anatase v brookite l cc dng gi bn v chuyn

thnh rutile khi nung nng.

Tt ccc dng tinh th ca TiO2tn ti trong tnhin nhl cc khong,

nhng chc rutile v anatase dng n tinh thl c tng hp nhit thp.

Hai pha ny cng c sdng trong thc tlm cht mu, cht n, cht xc tc...Tuy nhin, cc pha khc (k c pha p sut cao) chng hn nh brookite cng

quan trng v mt ng dng, tuy vy b hn ch bi vic iu ch brookite sch

khng ln rutile hoc anatase l iu kh khn.

Dng anatase Dng rutile Dng brookite

Hnh 1: Cu trc tinh thcc dng th hnh ca TiO2.


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Bng 1. Mt stnh cht vt l ca tinh thrutile v anatase.

Cc thng s Rutile Anatase

Cu trc tinh th Tdin Tdin

A () 4.58 3.78Thng smng

C () 2.95 9.49

Khi lng ring ( g/cm3) 4.25 3.895

Chit sut 2.75 2.54

rng vng cm (eV) 3.05 3.25

Nhit nng chy 1830 1850OCnhit cao chuyn

thnh rutile

Cu trc mng li tinh thca rutile, anatase v brookite u c xy dng

tcc a din phi tr tm mt (octahedra) TiO6ni vi nhau qua cnh hoc qua

nh oxi chung. Mi ion Ti4+c bao quanh bi tm mt to bi su ion O2-.

Hnh 2: Hnh khi bt din ca TiO2.

Cc mng li tinh thca rutile, anatase v brookite khc nhau bi sbindng ca mi hnh tm mt v cch gn kt gia cc octahedra. Hnh tm mt trong

rutile l khng ng u do c sbin dng orthorhombic (htrc thoi) yu. Cc

octahedra ca anatase bbin dng mnh hn, v vy mc i xng ca hl thp

hn h trc thoi. Khong cch Ti Ti trong anatase ln hn trong rutile nhng

khong cch Ti - O trong anatase li ngn hn so vi rutile. Trong cba dng tinh


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- 5 -

th th hnh ca TiO2 cc octahedra c ni vi nhau qua nh hoc qua cnh

(Hnh 1 v hnh 2).

b. Schuyn dng th hnh ca titan ioxit [1]

Hu ht cc ti liu tham kho u chra rng qu trnh thuphn cc mui

v cu to ra tin cht titan ioxit dng v nh hnh hoc dng cu trc anatase

hay rutile.

Khi nung axit metatitanic H2TiO3mt sn phm trung gian ch yu ca qu

trnh sn xut TiO2nhn c khi thuphn cc dung dch mui titan, th trc ht

to thnh anatase. Khi nng nhit ln th anatase chuyn thnh rutile.

Qu trnh chuyn dng th hnh ca TiO2 v nh hnh - anatase - rutile bnhhng r rt bi cc iu kin tng hp v cc tp cht, qu trnh chuyn pha t

dng v nh hnh hoc cu trc anatase sang cu trc rutile xy ra nhit trn

4500C. V d: Vi cc axit metatitanic sch, khng c tp cht, th nhit chuyn

pha t anatase thnh rutile snm trong khong 610730OC. Vi axit metatitanic

thu c khi thu phn cc mui clorua v nitrat ca titan th qu trnh chuyn

thnh rutile ddng hn nhiu (gn 5000C). Trong khi , vi axit metatitanic

c iu chbng cch thuphn cc mui sunfat th nhit chuyn pha scao

hn, nm trong khong 850900OC. iu ny c thl do c slin quan n sc

mt ca cc sunfat bazhoc l cc anion sunfat nm di dng hp ph.

Ngoi ion SO42-nhit chuyn anatase thnh rutile cng btng cao khi c

mt mt lng nh tp cht SiO2, cng nhkhi c mt HCl trong kh quyn bao

quanh.

Theo tc gi cng trnh [8] th nng lng hot ho ca qu trnh chuynanatase thnh rutile ph thuc vo kch thc ht ca anatase, nu kch thc ht

cng b th nng lng hot ho cn thit chuyn anatase thnh rutile cng nh.

Theo cc tc gicng trnh [5] th sc mt ca pha brukit c nh hng n

schuyn pha anatase thnh rutile: Khi tng nhit nung th tc chuyn pha

brukit sang rutile xy ra nhanh hn tc chuyn pha anatase sang rutile nn to ra


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- 6 -

nhiu mm tinh th rutile hn, c bit vi cc mu TiO2 cha cng nhiu pha

brukit th s chuyn pha anatase sang rutile xy ra cng nhanh. Qu trnh xy ra

hon ton 9000C.

1.1.2. Tnh cht ca titan ioxit kch thc nano mt [4], [10]

TiO2bn vmt ho hc (nht l dng nung), khng phn ng vi nc,

dung dch axt v vlong, kim, amonic, cc axit hu c.

TiO2tan khng ng ktrong cc dung dch kim to ra cc mui titanat.

2 2 3 2TiO 2NaOH Na TiO H O+ + (1.1)

TiO2tan r rt trong borac v trong photphat nng chy. Khi un nng lu vi

axit H2SO4c th n chuyn vo trng thi ho tan (khi tng nhit nung ca

TiO2th tan gim).. TiO2tc dng c vi axit HF hoc vi kali bisunfat nng

chy.0100 200 C

2 2 4 4 2 2TiO 2H SO Ti(SO ) 2H O

+ + (1.2)

[ ]2 2 6 2TiO 6HF H TiF 2H O+ + (1.3)

2 2 2 7 4 2 2 4TiO 2K S O Ti(SO ) 2K SO+ +

(1.4) nhit cao TiO2 c th phn ng vi cacbonat v oxit kim loi to

thnh cc mui titanat.o800 1100 C

2 3 3 2TiO MCO (MTi)O CO

+ + (1.5)

(M l Ca, Mg, Ba, Sr)o1200 1300 C

2 3TiO MO (MTi)O

+ (1.6)

(M l Pb, Mn, Fe, Co)2 2 3 2 3 2TiO +Na CO Na TiO +CO (1.7)

TiO2dbhidro, cacbon monooxit v titan kim loi khvcc oxit thp hn.0

4

1000 C2 2 2 3 2TiCl

2TiO H Ti O H O+ + (1.8)

o1750 C2 2 2TiO H TiO H O+ + (1.9)


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- 7 -

o800 C2 2 3 22TiO CO Ti O CO+ + (1.10)

o900 1000 C2 2 33TiO Ti 2Ti O

+ (1.11)

2 4 2 2 33TiO TiCl 2H O 2Ti O 4HCl+ + + (1.12)

2TiO Ti 2TiO+ (1.13)

1.1.3. Cc ng dng ca titan ioxit kch thc nano mt

Hin nay, sn lng titan ioxit trn thgii khng ngng tng ln (Bng 2):

Bng 2: Sn lng titan ioxit trn thgii qua mt snm.

Nm 1958 1967 2003Sn lng (tn) 800.000 1.200.000 4.200.000

Gn 58% titan ioxit sn xut c c dng lm cht mu trng trong cng

nghip sn xut sn. Cht mu trng titan ioxit cng c sdng mt lng

ln trong sn xut giy, cao su, vi sn, cht do, si tng hp v mt lng nh

trong cng nghip hng liu. Cc yu cu i hi i vi sn phm l rt a dng

phthuc vo cng dng ca chng.Titan ioxit l mt vt liu cbn trong cuc sng hng ngy ca chng ta.

Cc nh quan st cng nghip cho rng lng titan ioxit tiu thti mt quc gia

c mi quan hrt gn vi tiu chun cuc sng. V dti Nht Bn, sliu thng

k hng nm cho thy lng titan ioxit sn xut ra c quan hmt thit vi GNP

ca quc gia ny.

Ta c cc ng dng xc tc quang ca TiO2 c a ra nhtrong hnh 3.

Nhn vo hnh 4 ta c ththy lng TiO2sdng cho lnh vc quang xc tc

chim gn 50% trong nhng ng dng ca TiO2v tng dn theo thi gian [35].


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- 8 -

Hnh 3: Sng dng tnh cht quang xc tc ca TiO2.

Sn lng TiO2 sdng hng nm trong lnh vc quang xc tc:

Hnh 4: Lng TiO2 sdng hng nm trong lnh vc quang xc tc.

Tng hphu c

Quang xctc

Quang in

Hiu ngsiu anc

Phn ngc bit

Quang ngngkt nitrogen

Gim chtgy nhim

Khcht cv cv loi

trion

Ty u: Phnhy cc hpcht vi sinh

Oxi ha mtphn hoc

ton phn hpcht hu c

Quang tchnc to

hydro

Quang oxi ha

cc hp chthu cthnh

CO2

nh sng+TiO2 hot

tnh

Tn

Nm


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- 9 -

a. ng dng trong xc tc quang ha xl mi trng [1]

Khi titan thay i ha trto ra cp in t - l trng di tc dng ca nh

sng cc tm chiu vo, n sgip cho cc in tchuyn tvng ha trln vng

dn lm xut hin cp in t- ltrng vng dn v vng ha tr. Nhng cp ny

sdi chuyn ra bmt thc hin phn ng oxi ha kh, cc ltrng c ththam

gia trc tip vo phn ng oxi ha cc cht c hi, hoc c ththam gia vo giai

on trung gian to thnh cc gc tdo hot ng tip tc oxi ha cc hp cht

hu cbhp phtrn bmt cht xc tc to thnh sn phm cui cng l CO2v

nc t c hi nht.

b. ng dng lm cht n trong cc lnh vc sn tlm sch, cht do[2]TiO2 cn c sdng trong sn xut sn tlm sch, tn chnh xc ca loi

ny l sn quang xc tc TiO2. Thc cht sn l mt dng dung dch cha v scc

tinh thTiO2cchng 8 25 nm. Do tinh thTiO2c thllng trong dung dch

m khng lng ng nn cn c gi l sn huyn ph TiO2. Khi c phun ln

tng, knh, gch, sn stto ra mt lp mng mng bm chc vo bmt.

Nguyn l hot ng ca loi sn trn nhsau: Sau khi cc vt liu c a

vo s dng, di tc dng ca tia cc tm trong nh sng mt tri, oxi v nc

trong khng kh, TiO2shot ng nhmt cht xc tc phn hubi, ru, mc,

kh c hi, hu ht cc cht hu cbm trn bmt vt liu thnh H2O v CO2.

TiO2khng btiu hao trong thi gian sdng do n l cht xc tc khng tham gia

vo qu trnh phn hu.

Cchca hin tng ny c lin quan n squang - oxi ho cc cht gy

nhim trong nc bi TiO2. Cc cht hu cbo, ru, mc,... bm cht vo sn cthboxi ho bng cp in t- ltrng c hnh thnh khi cc ht nano TiO2hp

thnh sng v nhvy chng c lm sch khi mng sn. iu gy ngc nhin

l chnh lp sn khng btn cng bi cc cp oxi ho - khmnh mny. Ngi

ta pht hin ra rng, chng c tui thkhng km g sn khng c bin tnh bng

cc ht nano TiO2.


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- 10 -

c. Xl cc ion kim loi nng trong nc [12], [13]

Khi TiO2 b kch thch bi nh sng thch hp gii phng cc in t hot

ng. Cc ion kim loi nng sbkhbi in tv kt ta trn bmt vt liu.

Vt liu xc tc quang bn dn cng nghmi ha hn nhiu p dng trong xl

mi trng. Cht bn dn kt hp vi nh sng UV c dng loi cc ion

kim loi nng v cc hp cht cha ion v c. Ion bkhn trng thi t c hn

hoc kim loi t ddng tch c. V d:

2h+ TiO22e + 2h+ (1.14)

Hg2+(aq) Hg(ads) ( Bhp phln bmt vt liu) (1.15)

Hg2+

(ads)+ 2e Hg(ads) (1.16)2H2O 2H

++ 2OH- (1.17)

2OH-+ 2h+H2O + 1/2 O2 v.v... (1.18)

Rt nhiu ion kim loi nhy vi schuyn quang ha trn bmt cht bn dn

nhl Au, Pt, Pd, Ag, Ir, Rh... a schng u kt ta trn bmt vt liu. Ngoi

skhbng in t, cc ion cn boxi ha bi ltrng trn bmt to oxit. Nhng

cht kt ta hoc hp phtrn bmt c tch ra bng phng php chc hoc

ha hc.

d. Cc ng dng khc ca bt titan ioxit kch thc nano mt

TiO2cn c sdng trong nhiu lnh vc khc nh: Vt liu gm, cht to

mu, cht n, lm vt liu ch to pin mt tri, lm sensor nhn bit cc kh

trong mi trng nhim nng, trong sn xut bn ra t lm sch bmt trong

nc (txl m khng cn ho cht), lm vt liu sn trng do khnng tn x

nh sng cao, bo vbmt khi tc ng ca nh sng. Sdng TiO2to mng

lc quang xc tc trong my lm sch khng kh, my iu ho, v.v

1.1.4. Cc phng php iu chtitan ioxit kch thc nano mt

a. Cc phng php vt l [2]

iu chbt titan ioxit kch thc nano mt theo phng php vt l ta c

thsdng 3 phng php sau:


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- 11 -

- Phng php bc bay nhit:

S dng thit b bay hi titan kim loi nhit cao, sau cho kim loi

dng hi tip xc vi oxi khng kh thu c oxit kim loi. Sn phm thu c

l TiO2dng bt hoc mng mng.

- Phng php sputtering (bn ph ion):

Cc phn tc tch ra khi ngun rn nhqu trnh va p ca cc kh v

d Ar+, sau tch t trn . Phng php ny thng c dng iu ch

mng TiOxa tinh thnhng thnh phn chnh l rutile v khng c hot tnh xc

tc.

- Phng php n mn quang in:Phng php ny to ra TiO2c cu trc tong, kch thc nano mt, v vy

c din tch bmt rt ln nhng sn phm to thnh li dng rutile.

b. Cc phng php ho hc

Sau y chng ti xin gii thiu mt sphng php ha hc thng dng

iu chbt TiO2kch thc nano mt:

- Phng php iu chbt TiO2kch thc nano mt tcc cht u l ctitan.

- Phng php iu chbt TiO2kch thc nano mt ttitan butoxit.

- Phng php iu chbt TiO2 ttitan tetraisopropoxit (Ti(iPrO)4).

- Phng php iu chTiO2dng bt kch thc nano mt tcc mui v cca

titan.

- Phng php iu ch bt TiO2 kch thc nano mt t cc mui v c TiCl4,

Ti(SO4)2.

1.2. GII THIU V TITAN IXIT KCH THC NANO MT BIN

TNH

1.2.1. Cc kiu titan ioxit bin tnh [35]

Ngoi titan ioxit tinh khit, ngi ta c cc kiu titan ioxit bin tnh nhsau:


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TiO2c bin tnh bi nguyn tkim loi, TiO2c bin tnh bi nguyn t

khng kim loi, TiO2c bin tnh bi hn hp.

a. Cc vt liu nano TiO2c bin tnh bi nguyn tkim loiCc kim loi c th c dng bin tnh cc vt liu nano TiO2. Cc

phng php iu chcc vt liu nano TiO2bin tnh bi kim loi c thc chia

thnh ba loi: Phng php ha t, phng php x l nhit cao, v phng

php cy ion trn cc vt liu nano TiO2. Cc phng php ha t thng lin

quan n sthy phn ca mt cht u titan trong mt hn hp ca nc v cc

thuc thkhc, i km vi sgia nhit.

b. Cc vt liu nano TiO2c bin tnh bi nguyn tkhng kim loi

Cc nguyn tkhng kim loi khc nhau, nhB, C, N, F, S, Cl v Br, c

bin tnh thnh cng vo cc vt liu nano TiO2. Cc vt liu nano TiO2 c

bin tnh bi C thu c bng cch un nng titan cacbua hoc TiO2di dng

kh CO cc nhit cao (500-800oC) hoc bng cch t chy trc tip tm titan

kim loi trong mt ngn la kh tnhin.

Cc vt liu nano TiO2 c bin tnh bi S c tng hp bng vic

trn TTIP vi etanol cha thiourehoc bng cch un nng bt sulfuahoc sdng

phng php tn xhoc cc k thut cy ion vi dng ion S+. Cc phng php

bin tnh khc c thto ra cc vng ha trkhc nhau cc cht thm vo. V d,

S kt hp tthioure l S4+hoc S6+, trong khi un nng trc tip TiS2hoc phn

xvi S+to thnh anion S2-.

Cc vt liu nano TiO2 c bin tnh bi F c tng hp bng cch

trn TTIP vi etanol cha H2O NH4F, hoc bng cch un nng TiO2di hydroflorua hoc bng qu trnh nhit phn phun tmt dung dch nc ca H2TiF6hoc

sdng cc kthut cy ion vi dng ion F+.

c. Cc vt liu nano TiO2c bin tnh bi hn hp

Cc vt liu nano TiO2khng chc bin tnh bi nguyn tkim loi, phi

kim m cn bin tnh bi hn hp cc nguyn t, v dnhcc vt liu nano ng


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- 13 -

bin tnh bi Cl- hoc Br- c tng hp bng cch thm TiCl4vo etanol c

cha HBr. Wei v cng s tng hp cc ht nano TiO2c ng kch hot bi

N v La vi hot tnh xc tc tt hn di nh sng nhn thy, ti cht bin tnh

N c nhim vthu hp di trng ca TiO2v cht bin tnh La3+th ngn cn sto

thnh kt tca cc ht nano. Chang v cng scng thng bo vvt liu nano

TiO2c ng kch hot bi Cr v N vi shp thnh sng nhn thy dn n

mt hiu qukh mu xc tc quang xanh metylen, tr khi nng cht thm

nitthp. Hiu quxc tc quang trong vng nh sng nhn thy ca TiO2 kch

hot bi hn hp c tm thy l phthuc vo nng cht bin tnh, v cc

vtr hot ng ca hn hp cht bin tnh i vi cht xc tc quang di nh sngnhn thy.

1.2.2. Tnh cht ca titan ixit bin tnh

a. Cc tnh cht in ca cc vt liu nano TiO2 c bin tnh [35]

+ Cc vt liu nano TiO2 c bin tnh bi kim loi:

Theo nghin cu ca Soratin v Schwarz, cc trng thi in tca TiO2c

thphn chia thnh ba loi: lin kt ca cc trng thi O p

v Ti eg trong vngnng lng thp hn; lin kt ca cc trng thi O p

v Ti eg trong vng nng

lng trung bnh; v cc trng thi O ptrong vng nng lng cao hn . Phn di

cng ca vng dn thp hn (CB) gm c cc obitan Ti dxyng gp vo cc tng

tc kim loi kim loi dn n lin kt ca cc trng thi Ti t2g Ti t2g.

Phn pha trn ca vng ho trc phn chia thnh 3 vng chnh: Lin kt

vng nng lng thp chyu do cc orbital lin kt Op, lin kt vng nng

lng gia v trng thi O pvng nng lng cao hn do cc trng thi orbital

khng lin kt O pnh ca vng ho tr, ni m slai ho ca trng thi d gn

nhkhng ng k. Sng gp ca lin kt yu hn nhiu so vi lin kt .

Vng dn trong gin c phn chia thnh vng Ti eg(>5 eV) v vng t2g

(< 5eV). Trong , cc trng thi dxychim u thcc by ca vng dn. Nh

vy, nt c trng ca gin ny l cc trng thi khng lin kt tn ti ra di


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- 14 -

trng: Orbital O pnh ca vng ho trv cc trng thi Tidxyy ca vng

dn.

Gin sphn bcc mc nng lng ca cc orbital phn ti vi anatase

c a ra nhhnh 5 di y:

Hnh 5: Gin sphn bcc mc nng lng ca cc orbital phn t

i vi anatase.

(a)-Cc mc AO ca Ti v O; (b)-Cc mc tch trong trng tinh th;

(c)- Trng thi tng tc cui cng trong anatase. Cc phn ng gp nhiu

hay t c biu din bng cc ng lin hoc ng chm chm tng ng.Cc cu trc in t, c ngha cc mt ca cc trng thi (DOSs), ca TiO2

c bin tnh bi V-, Cr-, Mn-, Fe-, Co- c phn tch cc tnh ton u

on da trn thuyt mt chc nng vi phng php sng phng tng tuyn

tnh. Ngi ta thy rng khi TiO2c bin tnh vi V, Cr, Mn, Fe, hoc Co, v

tr c mt electron to thnh v cc electron c nh ch xung quanh mi cht


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thm. Khi s lng nguyn t cht thm tng ln, v tr c nh ch s dch

chuyn vpha nng lng thp hn. Nng lng ca vtr c nh chdo qu

trnh bin tnh bi Co thp n nm nh ca vng ha trtrong khi cc kim

loi khc a ra cc trng thi gia di trng. Cc electron tcht thm Ni c phn

khng nh ch, v vy ng gp hiu quvo sto thnh ca vng ha trvi cc

electron O p v Ti 3d. Cc trng thi nhvo cc cht bin tnh 3d dch chuyn

vnng lng thp hn khi slng nguyn tca cht bin tnh tng ln. Obitan

phn lin kt c to bi cc trng thi Cr (Mn) egv O pxut hin trong CB

thp hn. i vi TiO2c bin tnh bi Fe- v Co-, vtr c nh ch(e) l 0,2

eV do obitan phn lin kt ca cc trng thi Fe egv O p. Vtr ny c xuthin bi bn (hoc nm i vi Co) electron. Trng thi Fe (Co) egc phn tch

thnh cc obitan 2zd (f) v 2 2x -yd (g) trong di trng. i vi TiO2c bin tnh bi

Ni, obitan phn lin kt ca cc trng thi Ni t2gv O pc phn khng nh chdo

cc trng thi Ni egtcc obitan 2zd v 2 2x -yd trong di trng. Tng tc kim loi

O trnn mnh, v tng tc kim loi kim loi trnn yu nhkt qubin

tnh bng kim loi 3d.+ Cc vt liu nano TiO2c bin tnh bi nguyn tkhng kim loi

Cc nghin cu l thuyt v thc nghim gn y cho thy rng sthu hp

di trng ca TiO2cng c th thu c khi sdng cc cht thm l khng kim

loi. Ngi ta tnh ton cu trc di chuyn in tca TiO2dng anatase vi

cc cht thay thkhc nhau, gm C, N, F, P, hoc S. Trong nghin cu ny, cht

thm C to nn cc trng thi vtr thp trong di trng. Nakato v cc cng s

nghin cu TiO2 c bin tnh bi C v tm ra ba mc nng lng xp xti

0,86, 1,30, v 2,34 eV pha di di dn, trong gi tr thnht l ca bn thn

TiO2, v hai mc sau mi c to ra bi sthm vo ca C. c bit, gi trca

di trng 2,34 eV hay l sthu hp ca di trng c cho l gy ra bi strn ln

vi obitan ha tr2p ca O. Sbin tnh bng cch thay thca N l hiu qunht

trong vic thu hp di trng bi v cc trng thi p ca chng c khnng trn ln


17/90



- 16 -

vi cc obitan 2p ca O, trong khi cc tiu phn li tn ti dng phn t, v dnh

cc cht thm NO v N2, lm tng trng thi lin kt pha di cc di ha trca

obitan 2p ca O v cc trng thi phn lin kt nm su trong di trng (Niv Ni+s),

v ng thi chng bchn l khng c khnng tng tc vi cc di ca TiO2.

Ngoi ra, i vi sbin tnh bi nittrong cdng anatase v rutile, cc trng thi

c nh chca obitan 2p ca N ngay trn nh ca di ha trca obitan 2p

ca O. anatase, cc trng thi ca cht thm ny gy ra sdch chuyn nh sng

ca ra mp di hp thvpha vng nh sng nhn thy, trong khi, rutile nhn

chung li l sdch chuyn nh snh xanh c tm thy.

b. Cc tnh cht quang hc ca vt liu nano TiO2 c bin tnh [35]+ Cc tnh cht quang ca vt liu nano TiO2c bin tnh bi kim loi:

Mt sdch chuyn nh sng trong schuyn di trng hoc mt shp

th nh sng nhn thy thu c TiO2c bin tnh bi kim loi. i vi

TiO2c bin tnh bi V-, Mn-, hoc st, phhp thdch chuyn vvng nng

lng thp hn khi tng nng ca cht thm. Sdch chuyn nh sng c

quy do schuyn in tch gia cc electron d ca cht thm v CB (hoc VB) ca

TiO2. TiO2 c bin tnh bi ion kim loi c iu chbng phng php cy

ion vi cc ion chuyn - kim loi khc nhau v dV, Cr, Mn, Fe, v Ni tm thy

rng c mt sdch chuyn ln di hp thvpha vng nh sng nhn thy, vi

ththiu lc trong sdch chuyn nh sng l V > Cr > Mn > Fe > Ni. Cc

nh khoa hc thy rng di hp thca TiO2 c cy bi ion Cr dch chuyn

v vng nh sng nhn thy, vi khong dch chuyn nh sng ph thuc vo

hm lng ion kim loi c cy vo, TiO2c bin tnh ha hc bi ion Cr hoc

bnhim c chra l khng dch chuyn ra mp hp thca TiO2.

+ Tnh cht quang ca cc vt liu TiO2 c bin tnh bi cc nguyn t

phi kim:

TiO2c bin tnh bi phi kim c mt mu sc ttrng ti vng hoc thm

ch l mu xm sng, v bt u ca phhp th, nh sng dch chuyn vcc

bc sng di hn. cc vt liu nano TiO2 c bin tnh bi N, di trng hp


18/90



- 17 -

thbt u dch chuyn t380 nm ti 600 nm, i vi TiO2khng c bin tnh,

shp thmrng n 600 nm. Shp thquang ca TiO2 c bin tnh bi

N trong vng nh sng nhn thy c nh chchyu trong khong 400 n

500 nm, trong khi vi TiO2 thiu ht oxy li ch yu trn 500 nm. TiO2c

ng bin tnh bi N-F c iu chbng cch nhit phn phun hp thu nh sng

ti 550 nm trong phnh sng nhn thy. TiO2c bin tnh bi S cng thhin

shp thmnh trong vng t400 n 600 nm. Sdch chuyn ca nh sng

trong phhp thca TiO2 c bin tnh ni chung c qui l do sthu hp

di trng cu trc in tsau sbin tnh. TiO2 c bin tnh bi C cho ph

hp thc ui di trong vng nh sng nhn thy. Gn y pht hin ra rngTiO2 c bin tnh bi N cha cc trung tm khng tinh khit l cc nguyn t

nit, c nh chdi trng ca oxit, iu ny l ng tin cy i vi shp th

nh sng nhn thy vi schuyn ca cc electron tdi trng nh chcc trng

thi ln ci dn.

c. Cc tnh cht quang in ca vt liu nano TiO2 c bin tnh [35]

Cc tnh cht quang in ca mt vt liu c thnh gi bi mt ng cong

ph hot ng s dng mt thit b ci t dng sinh ra bi s chiu sng.

Trong thit lp ny, nh sng tmt chic n xenon i qua mt thit blc tia n

sc ri chiu vpha in cc, v cc dng quang in tcc in cc sc o

c bi mt hm sng. Hiu sut dng sinh ra bi schiu sng vn c l mt hm

ca bc sng, IPCE, c gi l mt phhot ng. IPCEc thc tnh

ton bi cng thc:

ph,IhcIPCE e P

=

(1.19)

Trong , ph,I l dng quang in, Pl cng mnh nht ca nh sng bc

sng , v h, c, v e ln lt l hng sPlanck, vn tc nh sng, v in tch cs.

ung cong IPCEthng c dng nhnhau v chiu hng nhmt phhp th.

Khi ng IPCEc chia ra bi shp th, hiu sut dng sinh ra bi schiu

sng hp th(APCEcng c gi l trng lng t) thu c.


19/90



- 18 -

1.2.3. Cc ng dng xc tc quang [35], [37], [38]

TiO2c nh gi l cht xc tc quang ha thn thin vi mi trng v

hiu qunht, n c sdng rng ri nht cho qu trnh quang phn hy cc

cht nhim khc nhau. Cc cht xc tc quang ha TiO2cn c thc sdng

dit khun, nh tin hnh tiu dit cc huyn ph E.coli. Do c khnng oxy

ha mnh nn TiO2 c chiu x thng c dng loi b cc t bo u

trong qu trnh cha trung th.Bn cht phn ng xc tc quang ca cht bn dn

khng phc tp. Nhvo shp thcc photon c nng lng ln hn nng lng

vng cm ca TiO2m cc electron bkch thch tvng ha trln vng dn, to

cc cp electron-ltrng. Cc phn tmang in tch ny di chuyn n bmt vphn ng vi cc cht ha hc hp phtrn bmt phn hy cc cht ha hc

ny. Qu trnh quang phn hy ny thng bao gm mt hoc nhiu gc hoc cc

phn ttrung gian nh*OH, O2-, H2O2, hoc O2, cng ng vai tr quan trng trong

cc phn ng xc tc quang. Khnng xc tc quang ca cht bn dn c iu

khin bi cc tnh cht hp thnh sng, th dhsv phhp thnh sng, tc

oxy ha v kh trn b mt bi electron v l trng v tc ti kt hp

electron-ltrng. Mt din tch bmt ln vi mt bmt hng sca cc cht

hp phdn n tc phn ng xc tc quang nhanh hn. Trong pht hin ny,

din tch bmt ring cng ln th hot tnh xc tc quang cng cao. Mt khc, din

tch b mt cng ln, s ti kt hp cng nhanh hn. kt tinh cng cao cc

khuyt tt khi cng hn ch, v hot tnh xc tc quang cng cao. Xl nhit

cao thng lm tng kt tinh ca vt liu nano TiO2, do qu trnh ny c thto

skt tcc ht nano nhv lm gim din tch bmt.a. Vt liu nano TiO2sch: thhu tin

Khi kch thc cc ht TiO2gim xung, slng cc nguyn tnh chtrn

bmt tng ln tng ng vi t ln din tch bmt trn th tch cng tng ln,

iu ny c thlm gia tng thm hot tnh xc tc. Nng lng di trng tng ln

vi sgim kch thc ht nano c khnng lm tng thoxy ha khca cc l


20/90



- 19 -

trng di ha trv cc electron di dn, lm xy ra cc phn ng quang oxy

ha kh. Cc phn ng ny c thkhng din tin khc cc vt liu khi, tc l d

dng xy ra. Mt iu khng thun li cc ht nano TiO2 l chng chc th

sdng phn trm rt nhnh sng mt tri cho qu trnh xc tc quang. Trn thc

t, tn ti mt kch thc ti u i cho mt phn ng xc tc quang c bit.

Anpo v cc cng s nghin cu hot tnh xc tc quang ca cc ht nano

TiO2trn phn ng hydro ha CH3CCH vi nc, v h thy rng hot tnh tng

ln khi ng knh cc ht TiO2gim, c bit di 10 nm. Ha ra gi thuyt

rng sphthuc ca hiu sut vo kch thc ht c ngun gc tskhc nhau v

hot tnh ha hc chkhng tcc tnh cht vt l ca cc cht xc tc ny.

Hnh 6: Cc tnh cht xc tc quang ca cc mu TiO2xp meso c iu

chv nung cc nhit khc nhau cng nhTiO2dng ht nano P25

(RB, c0= 1,0.10-5M, pH = 6,0) di nh sng UV.

Wang v cng s thy rng c mt kch thc ti u i vi cc ht nano

TiO2cho hiu quxc tc quang tt nht trong vic phn hy clorofom. H quan

st s tng cng hot tnh khi kch thc ht gim t21 ti 11 nm, nhng hot

tnh li gim xung khi kch thc gim xung di 6 nm. H kt lun rng i

vi phn ng gia cc ht th kch thc ht ti u l khong 10 nm. cc ht nano

Thi gian (pht)

c/co


21/90



- 20 -

TiO2ln, sti hp to khi xy ra l qu trnh chyu, n c thlm gim xung

bng cch gim kch thc ht; khi kch thc ht gim xung di mt gii hn

xc nh no , qu trnh ti hp trn b mt tr nn ch yu, do hu ht cc

electron v ltrng tin li gn bmt v sti hp bmt xy ra nhanh hn qu

trnh chuyn in tch mt phn cch.

Chae v cng s nghin cu hot tnh xc tc quang ca bn cht nano

TiO2trong sphn hy 2-propanol, v h thy rng cc ht kch thc 7 nm c

hot tnh xc tc quang tt hn gp 1,6 ln so vi TiO2P25, ng thi cc ht kch

thc 15 v 30 nm c hiu quxc tc quang km hn.

TiO2xp meso, cc thanh nano v cc ng nano TiO2 c chng minh lc hiu quxc tc quang cao di cc iu kin tin hnh ph hp. Peng v cng

s iu chra TiO2xp meso vi mt din tch bmt ring cao, iu ny cho

thy hot tnh quan trng i vi qu trnh oxy ha ca Rhodamine B do din tch

bmt ln, kch thc tinh thnh, v cu trc meso dng anata kt tinh tt. Hnh

60 cho bit hot tnh xc tc quang ca cc mu TiO2xp meso c iu chv

nung cc nhit khc nhau so vi TiO2P25 dng ht nano. Tt ccc mu TiO2

xp meso u thhin c hot tnh tt hn TiO2P25 Deguessa. Khnng phn ng

ti u thu c mu nung 400oC, v hot tnh quang hc cng gim khi nhit

nung cng tng.

Yang v cng s tm thy rng cc ng nano TiO2c xl bi dung dch

H2SO4c hot tnh xc tc quang trong qu trnh phn hy axit cam II theo tht

di y: ng nano TiO2c x l bi dung dch H2SO4 1,0 mol/l > ng nano

TiO2c xl bi dung dch H2SO40,2 mol/l > cc ng nano TiO2khng c

xl > cc ht nano TiO2, do cc ng nano TiO2c x l bi H2SO4bao gm

cc ht nhhn v do c din tch bmt ring cao hn.

TiO2aerogel cng c cho l ha hn hot tnh xc tc quang tt. Degan v

cng s iu chc TiO2aerogel vi mt xp l 90% v din tch bmt

l 600 m2/g, v hthy rng khnng quang phn hy ca axit salicylic ca TiO2


22/90



- 21 -

aerogel, sau 1h di nh sng tngoi gn nhanh hn khong 10 ln so vi TiO2

Degussa.

Trn hnh v7 trnh by cc profile quang phn hy ca aerogel trc (E1) v

sau khi (E1a), khi so snh vi bt P25 Degussa thng phm.

Hnh 7: Cc profile quang phn hy axit salicylic trn TiO2aerogel khng

c (E1) v c (E1a) khi so snh vi P25 Degussa thng phm.

b. Cc vt liu nano TiO2kch hot bi kim loi: thhthhai

Trong nhiu thp k trc, vt liu nano TiO2 c kch hot bi kim loi

nhm nng cao hiu quxc tc quang trong qu trnh phn hy cc cht nhim

hu ckhc nhau di nh sng nhn thy c nghin cu rng. Choi v cng

s cho mt nghin cu c h thng vhot tnh xc tc quang ca cc ht

nano TiO2 c kch hot bi cc nguyn tkim loi chuyn tip trong soxyha CHCl3v skhCCl4v tm c rng hot tnh xc tc quang lin quan n

cu hnh electron ca ion cht thm trong cc ion cht thm c lp velectron

gn bo ha c mt cht hoc khng c nh hng ti hot tnh. Skch hot bi

Fe3+, Mo5+, Ru3+, Os3+, Re5+, V4+, v Rh3+0,1-0,5% gim ng khot tnh quang

hc. Sc mt ca cc cht thm dng ion kim loi trn TiO2matrix nh hng r

Nn

g

(M)

Thi gian (pht)

Degussa


23/90



- 22 -

rt ti tc ti hp in tch v tc chuyn di in tmt phn cch. Hot

tnh quang hc ca TiO2 c kch hot xut hin l mt hm phc ca nng ,

mc nng lng ca cht thm, trong mng li TiO2, cu hnh electron d ca

chng, sphn bcht thm, nng cht cho electron v cng nh sng.

Cc mng TiO2cht nano c kch hot bi ion Sn4+ c iu ch

bng phng php bay hi lng ng ha hc CVD thhin mt hot tnh xc tc

quang phn hy phenol cao hn so vi TiO2tinh khit di cnh sng nhn thy

v nh sng UV, v cht thm Sn4+ c tm thy l c li cho sphn bcc

cht mang sinh ra bi schiu nh sng kch thch trong cvng nhn thy v UV.

Hnh 8 cho bit qu trnh xc tc quang phn hy phenol vi giai on phn ngdi nh sng nhn thy v UV sdng cc ht nano TiO2 c kch hot bi

Sn4+lm cht xc tc quang[35].

Hnh 8: Sthay i nng phenol trong phn ng di nh sng (A) UV

v (B) nhn thy.

(a-Cht xc tc TiO2nguyn cht; b-TiO2 c kch hot bi Sn

4+

)TiO2nano tinh th c kch hot bi Fe vi hm lng Fe thp hn (mc

ti u l 0,05% vkhi lng) c chra l c hot tnh xc tc quang cao hn

so vi TiO2trong qu trnh xl nc thi lm giy v n chra l c nhiu hiu

qu trong sdit khun xc tc quang in tvi khun E. coli hn TiO2 nguyn

cht. Cht xc tc quang TiO2 c kch hot bi V quang oxy ha etanol

Thi gian (pht)Thi gian (pht)

Nng

(10-6M)

Nng

(10-6M)


24/90



- 23 -

di bc xnhn thy v di bc xUV c thso snh hot tnh c vi TiO2

nguyn cht. Cc ht nano TiO2 c kch hot bi ion Pt4+biu hin hot tnh

xc tc quang i vi sphn hy dicloaxetat v 4-clophenol, di nh sng nhn

thy cao hn, v cht xc tc nano Ag-TiO2 thhin hot tnh xc tc quang tng

ln trong qu trnh phn hy 2,4,6-triclophenol do sphn bcht mang in tch

sinh ra bi schiu sng l tt hn v lm tng qu trnh khoxy gy ra sphn

hy quy m ln hn ca cc nguyn t.

Wei v cng s tng hp cc ht nano TiO2c ng kch hot bi N v

La vi hot tnh xc tc tt hn di nh sng nhn thy, ti cht thm N c

nhim vthu hp di trng ca TiO2v cht thm La3+

th ngn cn sto thnh ktt ca cc ht nano. Chang v cng s thng bo v vt liu nano TiO2c

ng kch hot bi Cr v N vi shp thnh sng nhn thy dn n mt hiu qu

kh mu xc tc quang xanh metylen, tr khi nng cht thm nit thp.

Bessekhouad v cng s thy rng cc ht nano TiO2c kch hot bi cc kim

loi kim nng thp l cc loi vt liu trin vng cho sphn hy cc cht

nhim hu c. Peng v cng s thy rng vt liu nano TiO2 c kch hot

bi Be2+, khi cc ion kch hot bmt nng, cht thm sthun li, cn khi n

su trong khi th cht thm li to bt li.

Tuy nhin, khng phi tt cvt liu nano TiO2c kch hot bi kim loi

u c hot tnh xc tc quang cao hn vt liu nano TiO2nguyn cht. Martin

pht hin ra cc ht nano TiO2c kch hot bi V c hot tnh xc tc quang

trong qu trnh quang oxy ha 4-clophenol thp hn so vi cc ht TiO2 nguyn

cht. Vanidi c mt lm gim hot tnh quang xc tc ca TiO2bng cch thc y

sti kt hp cht mang in tch vi by in tcc trung tm VO2+hoc vi l

trng cc trung tm V4+, iu ny phn dng cc cht mang in tch khi mt

phn cch gia dung dch v cht rn. Hermann v cng s thy rng mc d

TiO2c kch hot bi Cr (0,85% nguyn t) hp th trong vng nh sng nhn

thy, nhng hot tnh ca n i vi qu trnh oxy ha axit oxalic, propen, v 2-

propanol v i vi strao i ng vO btrit tiu di nh sng nhn thy v l


25/90



- 24 -

nhhn di nh sng UV hn l trng hp TiO2nguyn cht, do sti kt hp

electron-l trng tng ln cc v tr ion Cr3+. Luo v cng s thng bo rng

hot tnh quang ca TiO2 c lm nhy vi 1,5mol % Mo, 1mol % V, 0,1mol %

V cng thm 1mol % Al, hoc 0,1 mol % V cng thm 1mol % Pb gim xung, t

cc electron d ca Mo(4d) v V(3d), ng vai tr cht mang l ch yu trong

TiO2, c thdp (quench) hiu qucc ltrng sinh ra do schiu sng nng lng

cao cc mc nhiu xbng cch kch hot gia cc di trng ca TiO2.

c. Cc vt liu nano TiO2c kch hot bi phi kim: thhthba [35]

Cc vt liu nano TiO2 c kch hot bi phi kim c coi nhcht

xc tc th h thba. Cc vt liu nano TiO2 c kch hot bi cc phi kimkhc nhau c nghin cu rng ri vhot tnh xc tc quang di nh sng

nhn thy. Cc vt liu nano TiO2c kch hot bi phi kim c chng minh

l c thlm tng hot tnh xc tc quang ca vt liu nano TiO2nguyn cht, c

bit vng nh sng nhn thy.

Hnh 9 biu din sphn hy ca xanh metylen sdng TiO2 kch hot bi

N, c o bi Asahi v cc ng nghip. Qu trnh ny cho thy TiO2 kch

hot bi N c hot tnh xc tc quang cao hn nhiu so vi TiO2nguyn cht khi

tin hnh vi nh sng nhn thy, trong khi li thhin hot tnh km hn khi

tin hnh vi nh sng UV. Hiu quxc tc quang trong vng nh sng nhn thy

ca TiO2 kch hot bi N c tm thy l phthuc vo nng nit, v cc

vtr hot ng ca N i vi cht xc tc quang di nh sng nhn thy c xc

nh bi pic trng thi nguyn t-N 396 eV trn phXPS. Trong nghin cu

ca Irie v

ng nghi

p, ho

t tnh xc tc quang c

a TiO2

c kch hot b

i N

phthuc vo nng c quy l do cu trc di ca vt liu ny, trng hp

c nng N thp hn (


26/90



- 25 -

ng vi cc trng thi trung gian bmt ca qu trnh oxy ha nc hoc kh

oxy. Cc ng nano TiO2 kch hot bi N cng thhin hot tnh oxy ha xc tc

quang cao i vi qu trnh phn hy khi isopropanol thnh axeton v cacbon dioxit

khi chiu sng bi nh sng nhn thy.

Hnh 9:Cc tnh cht xc tc quang ca TiO2-xNxv TiO2cn cvo tc phn

hy do sthay i nh sng lm mc qu trnh hp thnh sng ca xanh

metylen l mt hm sca bc sng ca cc blc cao

di nh sng hunh quang.

Hnh ghp biu din tc phn hy xanh metylen trong dung dch nc di

nh sng nhn thy nhmt hm sphthuc vo biu phn hy trn phXPS

vi pic 396 eV tng ng vi din tch tng cng ca N 1s.

Nng tng ca N l: 1,0 nguyn t% (a),

1,1 nguyn t% (b),1,4 nguyn t% (c),

1,1 nguyn t% (d),

1,0 nguyn t% (e).

Hot tnh xc tc quang ca TiO2 kch hot bi lu hunh cng c

nghin cu. TiO2 kch hot bi S c pht hin l thhin mt hot tnh xc tc

Bc sng (nm)


27/90



- 26 -

quang cao hn vng nh sng nhn thy nhng li thp hn vng nh sng UV.

TiO2 kch hot S c iu chbi cc phng php khc nhau, thhin hot

tnh xc tc quang khc nhau khi c chiu sng bng nh sng nhn thy do s

cht mang in tch l khc nhau cc mu ny.

Mt hot tnh xc tc quang ng ch i vi qu trnh phn hy xanh

metylen v isopropanal trong vng nh sng nhn thy c chng minh i vi

TiO2 kch hot bi C iu ch t cht u TiC. TiO2 kch hot bi C c

iu chbng cch nhit phn kim loi Ti trong ngn la tnhin thhin mt hot

tnh quang trong qu trnh phn tch nc cao hn nhiu so vi TiO2nguyn cht.

Cc ht nano TiO2 kch hot bi C cng thhin hot tnh quang cao trong qutrnh phn hy axit tricloaxetic di nh sng nhn thy.

Trong nghin cu hin tng quang phn hy axeton, Yu v cng s thy

rng, TiO2 kch hot bi F thhin hot tnh xc tc quang trong qu trnh oxy

ha axeton thnh CO2cao hn P25 Degeussa. Cc vt liu nano TiO2 kch hot

bi N/F c hot tnh xc tc quang di nh sng nhn thy trong qu trnh phn

hy caxtandehit v tricloetylen u cao do sto thnh cc lkhuyt oxy trn b

mt hn l do stng cc tnh cht hp thquang. Luo v cng s tm ra rng

TiO2 c ng kch hot bi brom v clo thhin mt hot tnh xc tc quang

cao hn nhiu so vi TiO2 kch hot bi brom hoc bi clo.

1.2.4. Cchca phn ng quang xc tc vi titan ioxit kch thc nano mt

Nguyn l cbn vkhnng quang xc tc trn cc cht bn dn l khi c

bin tnh bi nh sng c nng lng ln hay bng rng vng cm ca cht bn

dn (thng l tia tngoi do rng vng cm ca n kh ln ~3.2eV) sto ra

cp electron- l trng (e, h+) vng dn v vng ha tr. Nhng cp electron l

trng ny sdi chuyn ra bmt thc hin phn ng oxihoa- kh. Cc ltrng

c th tham gia trc tip vo phn ng oxihoa cc cht c hi, hoc c ththam

gia vo giai on trung gian to thnh cc gc t do hot ng nh( OH , 2O ).

Tng tnhthcc electron stham gia vo cc qu trnh khto thnh cc gc


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tdo. Cc gc tdo stip tc oxihoa cc cht hu cbhp phtrn bmt cht

xc tc thnh sn phm cui cng khng c hi l CO2v HO2. Cchxy ra nh

sau:

TiO2 + hvTiO2(h+ + e-) (1.20)

TiO2(h+) + H2O

OH + H+ + TiO2 (1.21)

TiO2(h+) + OH-OH+ TiO2 (1.22)

TiO2(h+) + RR+ TiO2 (1.23)

TiO2(e-) + O2 2O

+ TiO2 (1.24)

TiO2(e-) + H2O2OH

-+ OH + TiO2 (1.25)

2O + H+ 2HO

(1.26)

2HO O2+ H2O2 (1.27)

H2O2+ O2O2 + OH-+ OH (1.28)

Tcc phng trnh (1.21)-(1.23) trn ta thy rng in tchuyn tcht

hp ph sang TiO2. T phng trnh (1.24) ta thy phn tO2 c mt trong mi

trng s nhn in t tr thnh 2O . T cc phng trnh trn cho thy qu

trnh oxi ho phn huchyu ph thuc vo nng ca gc OH hp ph trn

bmt TiO2 (phng trnh 1.21) v lng oxi ho tan (phng trnh 1.24).

Sbsung thm 2 2H O vo slm tng hiu quphn ng (phng trnh 1.25)

v gc 2O sinh ra cng tham gia vo phn ng (phng trnh 1.26 v 1.28). Cc

gc sinh ra c tnh oxi ha rt mnh (chyu l OH v 2HO

).

Hp cht hu csbhp phtrn bmt TiO2v boxi ho bi OH v

2

HO .

Sn phm cui cng ca phn ng quang ho l 2 2CO ,H O.

Kch thc ht v cu trc TiO2nh hng nhiu n khnng xc tc quang

ho. Bt TiO2c kch thc cng nhth hot tnh xc tc cng cao. Hu ht cc

ti liu u chra rng TiO2dng bt kch thc nanomt c cu trc anatasese c

hot tnh xc tc cao nht [10].


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1.2.5. Cc phng php bin tnh titan ioxit kch thc nano mt

a. Cc phng php bin tnh chung [35]

Cc phng php bin tnh titan ioxit kch thc nm vi mc tiu ci thinhot tnh quang hc ca vt liu nano TiO2 l chuyn dch di trng t cng t

ngoi vvng nh sng nhn thy. C mt sphng php thc hin mc tiu

ny.

- Thnht, chng ta c thbin tnh vt liu nano TiO2 vi nhng nguyn t

m chng c khnng thu hp di trng do thay i tnh cht quang hc ca vt

liu nano TiO2.

- Thhai, chng ta c thhot ha TiO2bi cc cht mu v choc hu c,

cch ny cng c thci thin tnh cht quang hc ca n trong vng nh sng nhn

thy.

- Thba, chng ta c cp i electron dao ng cng hng trong di dn trn

b mt ca cc ht nano kim loi vi electron trong di dn ca nano TiO2 nh

trong cc vt liu nano compozit kim loi - TiO2.

Thm vo , sbin tnh bmt cc ht nano TiO2bi cc cht bn dn khcc thlm thay i khnng chuyn in tch ca TiO2vi mi trng xung quanh,

nh nng cao ng dng ca cc thit bsdng vt liu ny.

b. Cc phng php bin tnh titan ioxit bng nit[39-44]

Gn y c nhiu cng trnh nghin cu vlnh vc ny c cng b, cht

xc tc TiO2cy thm nguyn tN c iu chdi dng bt hoc phtrn cc

loi cht mang khc nhau nh:

+ Thi bt TiO2nhiu gitrong bung hn hp kh N2/Ar, sau nung trong

dng kh N2.

+ Xl bt TiO2anatase trong kh NH3/Ar.

+ Nung hn hp TiO2- P25 vi ure trong khng kh.

+ Thy phn dung dch mui v cca titan nhTiCl3, TiCl4, Ti(SO4)2trong

dung dch ammoniac.


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+ Thy phn Ti(OBu)4trong dung dch amoniac.

Mt sphng php cthnh:

+ Phng php sol-gel: To hidroxit titan bng cch nh8.93 gam dung dch

TBOT vo dung dch cha 100 ml nc ct vo 20 ml propanol, khuy trong 30

pht. Nh chm 20 ml H2O2 30% vo hn hp trn to khi gel lng ng cht.

a tt5.3 ml dung dch ur 4M vo hn hp , khuy u trong 1 gi. Kt ta

c lc v sy 800C trong 24 gi, sau nung 4000C trong 4 gi. Mu to

thnh c mu vng nht. Cc vt liu nano TiO2c bin tnh bi N c tng

hp bng phng php thy nhit TTIP trong hn hp nc/amin v xl kp thi

sol TiO2 bi cc amin hoc trc tip t mt phc cht titan-bipyridin hoc bngcch nghin TiO2trong dung dch nc NH3.

+ Cc vt liu nano TiO2c bin tnh bi N cng c th thu c bng

cch un nng TiO2di lung NH3500-6000Choc bng cch nung sn phm

thy phn Ti(SO4)2vi cht u l amoniac hoc bi sphn hy TiCl4pha kh

vi mt ngn la thplasma vi sng kh quyn hoc cc kthut phn x/cy ion

vi nithoc dng kh N2+.

+ Phng php tm: Kt ta TiO2.nH2O sdng lm cht u cho qu trnh

bin tnh nitc chun b. Sau huyn ph TiO2.nH2O c chho vi dung

dch NH3c nng khc nhau trong 30 pht. Tch phn rn bng ly tm, sy kh

trong tchn khng 800C trong 12h, nung nhit xc nh, tc 100C/pht.

Nghin sn phm trong ci m no.

1.3. CC PHNG PHP NGHIN CU

1.3.1.Phng php nhiu xtia X (XRD) [9,11]

Phng php nhiu x tia X cung cp trc tip nhng thng tin v cu trc

tinh th, thnh phn pha v kch thc trung bnh ca cc ht scp TiO2.

Nguyn l chung ca phng php nhiu xtia X l da vo vtr v cng

cc vch nhiu x trn gin ghi c ca mu xc nh thnh phn pha,


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cc thng smng li tinh th, khong cch gia cc mt phn xtrong tinh th.

Xt hai mt phng song song I v II c khong cch d (Hnh 10). Chiu chm tia

Rngen to vi cc mt phng trn mt gc . cc tia phn xc thgiao thoa

th hiu quang trnh ca hai tia 11 v 22 phi bng snguyn ln bc sng .

AB + AC = nhay 2dsin n = . l phng trnh Bragg.

B C

O

A

1

2

1'

2'

d

I

II

Hnh 10: Sphn xtrn bmt tinh th.

Da vo gi trbn chiu rng ca pick (nh) c trng trn gin nhiu x

ngi ta c th tnh c kch thc trung bnh ca cc ht tinh th (ht s cp)

theo cng thc Scherrer tnh ton. i vi vt liu TiO2, trn gin nhiu xtia X

xut hin pick c trng ca pha anatase v rutile ln lt gc Bragg l 12,680

v13,730. Tgin nhiu xtia X, ngi ta c thtnh c kch thc trung bnh

ca cc ht TiO2theo cng thc Scherrer:

0.89r

cos

=

(1.14)

Trong : r

l kch thc ht trung bnh (nm). l bc sng bc xK ca

anot Cu, bng 0.154056 nm, l rng (FWHM) ca pick ti na cao ca pick

cc i (radian), l gc nhiu xBragg ng vi peaek cc i ().

T gin nhiu x tia X ta cng c th tnh c thnh phn ca cc pha

anatasese v rutilee trong mu TiO2theo phng trnh (1.15) [21]:

A

R

1

1 0.8=

+

; X =

I

I26,11

1

+

(1.15)


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- 31 -

Trong : l hm lng rutile (%). X l hm lng anatase (%). IA l cng

nhiu xca anatase ng vi mt phn x (101). IR l cng nhiu xca

rutilee ng vi mt phn x(110).

Trong bn lun vn ny, gin XRD ca cc mu c ghi trn nhiu xk

tia X D8- Advance 5005 (Hnh 11), vi tia K ca anot Cu c = 0,154056 nm,

nhit ghi 25oC, gc 2: 1070, tc qut 0,030/s.

Hnh 11: Nhiu xktia X D8- Advance 5005 (CHLBc).

1.3.2. Phng php kho st khnng quang xc tc ca titan ioxit

Trong lun vn ny tc gi th hot tnh quang xc tc ca bt TiO2 kch

thc nm iu chc thng qua khnng phn hy mu dung dch xanh metylen

v khion amoni trong nc ca n.

Cch tin hnh th nghim nh sau: Cn mt lng chnh xc xanh metylen

hoc amoni clorua v nh mc bng bnh nh mc 1l bng nc ct, ri cho vo

cc 1l lm phn ng. Sau cn mt lng chnh xc bt TiO2vi kch thc v

lng ph hp cho tng th nghim ri cho vo cc phn ng. t cc ln my

khuy t bt TiO2 phn tn u vo dung dch (khuy lin tc trong sut qu

trnh th nghim). Chiu dung dch trn bng n Compac cng sut 40W trong 3h,

dung dch sau c ly em ly tm loi TiO2v o mt quang (ABS). So

snh mt quang ca dung dch xanh metylen trc v sau khi qua thit bv t


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xc nh c phn trm lng cht bphn hy v nh gi c khnng xc

tc ca bt TiO2iu chc.

1.3.3. Ph

ng php TEMTrn hnh 12 a ra snguyn l hot ng ca knh hin vi in ttruyn

qua.

Hnh 12: Knh hin vi in ttruyn qua (TEM).

Hin vi in t truyn qua (Transsmision Electronic Microscopy) l phngphp hin vi in tu tin c pht trin vi thit ku tin m phng phng

php hin vi quang hc truyn qua. Phng php ny sdng mt chm in t

thay thchm sng chiu xuyn qua mu v thu c nhng thng tin vcu trc

v thnh phn ca n ging nhcch sdng hin vi quang hc.

Phng php hin vi in t truyn qua c u thhn phng php SEM

chn c phng i rt ln (phng i 400.000 ln vi nhiu vt liu, v vi

cc nguyn tn c tht c phng i ti 15 triu ln).

Cc bc ghi nh TEM cng tng tnhvi phng php SEM. Khi chiu

mt chm in tln mu vt, mt phn dng in tsxuyn qua mu ri c

hi tto thnh nh, nh ny c truyn n bphn khuch i, sau tng tc

vi mn hunh quang to ra nh c thquan st c.


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Mu vt liu chun bcho nh TEM phi mng dng in tc thxuyn

qua ging nhtia sng xuyn qua vt thtrong knh hin vi quang hc, do vic

chun bmu squt nh ti cht lng ca nh TEM. Phng php hin vi in

t truyn qua cho bit nhiu chi tit nano ca mu nghin cu: Hnh dng, kch

thc ht, bin gii ht, v.v Nhcch to nh nhiu x, vi nhiu xv nano nhiu

x, knh hin vi in t truyn qua cn cho bit nhiu thng tin chnh xc vcch

sp xp cc nguyn ttrong mu, theo di c cch sp xp trong chi tit tng

ht, tng din tch c m2v nhhn.

Cc loi knh hin vi in thin i cn trang b thm cc phng tin

phn tch thnh phn ho hc ca mu tng din tch nhhn m2

nhng lpchvi ba nguyn tbmt [11].

1.3.4. Phng php phn tch nhit

Phng php phn tch nhit cng l mt trong nhng phng php ha l

thng c dng phn tch cu trc ca vt liu, cung cp cho ta nhng thng

tin vtnh cht nhit ca vt liu.

Mc ch ca phng php phn tch nhit l da vo hiu ng nhit c thnghin cu nhng qu trnh pht sinh khi un nng hoc lm ngui cht.

Trn gin phn tch nhit thng thng ngi ta quan tm ti 2 ng cong

quan trng l DTA v TGA. ng DTA cho bit sxut hin ca cc hiu ng

nhit, ng TGA cho bit bin thin khi lng mu trong qu trnh gia nhit. Mi

qu trnh bin i ha hc nhcc phn ng pha rn, sphn hy mu hay cc bin

i vt l nh s chuyn pha u c mt hiu ng nhit tng ng. Nhng

DTA chng ta c thbit c khi no c hiu ng thu nhit (cc tiu trn ng

cong) v hiu ng ta nhit (cc i trn ng cong). Cc qu trnh trn c th

km theo sthay i khi lng ca mu nghin cu, v dqu trnh thng hoa bay

hi hay cc phn ng phn hy, hoc khng i km vi sthay i khi lng ca

mu nhqu trnh chuyn pha, ph vmng tinh th V vy, kt hp cc dliu

thu c t2 ng TGA v DTA ta c thbit c cc tnh cht nhit ca mu.


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Da vo vic tnh ton cc hiu ng mt khi lng v cc hiu ng nhit tng

ng m ta c thdon c cc giai on cbn xy ra trong qu trnh phn hy

nhit ca mu [14].

1.4. MC TIU V CC NI DUNG NGHIN CU CA LUN VN

1.4.1. Mc tiu ca lun vn

Nghin cu iu ch bt titan ioxit bin tnh kch thc nano mt c hot

tnh quang xc tc cao tcht u TiCl4.

1.4.2. Cc ni dung nghin cu ca lun vn

thc hin c mc ch trn, tc gi trin khai cc ni dung nghin cu

sau:

- Nghin cu cc yu t nh hng n kh nng quang xc tc ca titan

ioxit bin tnh.

- Xc nh iu kin thch hp cho qu trnh iu chc bt titan ioxit

bin tnh N c hot tnh quang xc tc cao theo phng php thy phn v phng

php tm.- Xy dng quy trnh iu chsn phm bt titan ioxit bin tnh bng N kch

thc nm theo phng php thy phn v phng php tm tcht u TiCl4.

- Kho st khnng phn hy NH4+trong mi trng nc bng cc loi titan

ioxit.


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- 35 -

PHN II: THC NGHIM

2.1. HA CHT V THIT B

2.1.1. Ha cht

Cc ha cht sdng cho vic tin hnh thc nghim bao gm:

+ TiCl499% (Merck) loi P.

+ (NH4)2SO4tinh th(Trung Quc) loi P.

+ Etanol tuyt i (Trung Quc) loi P.

+ Xanh metylen (C16H18ClN3S.3H2O) (Trung Quc) loi P.

+ KI tinh thloi P.

+ HgCl2tinh thloi P.

+ Mui Xagnhet (KNaC4H4O6) loi P.

+ Nc ct hai ln.

2.1.2. Dng cv thit b

+ Cc thy tinh 100ml, 150ml, 250ml.

+ a thy tinh.

+ Pipet 5ml, 10ml, 25ml.

+ Nhit k.

+ Bnh tia nc ct.

+ ng li tm V=15ml

+ Chn nung.

+ Bp in (Trung Quc)+My khuy tgia nhit Bibby Sterilin HC 502 (Anh)

+ Bn nhit (Vit Nam)

+My ly tm Hettich Zentrifugen D78532 Tuttlingen (c)

+ Cn kthut Sartorius(c)

+ Tsychn khng SheLab 1425-2 (M)


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- 36 -

+ Cn phn tchPrecisa (Thy S)

+ Bm lc ht chn khng Neuberger (c)

+ L nung Lenton(Anh).

2.2. PHNG PHP THC NGHIM

2.2.1. Phng php thc nghim iu chbt titan ioxit kch thc nano mt

bin tnh N bng tc nhn (NH4)2SO4theo phng php thy phn TiCl4

Cht u c s dng iu ch bt TiO2 kch thc nano mt bin tnh N

bng tc nhn (NH4)2SO4 l TiCl4 loi sn phm ca Merck, sch 99%. Mi

trng cho phn ng thy phn l hdung mi hn hp ru - nc - (NH4)2SO4

Hn hp ban u etanol/nc,

(NH4)2SO4,o0 C

Hn hp cha 4TiCl

Dung dch trong sut

Kt ta

Bt 2TiO

Khuy, trn mnh4TiCl nhtng git

Khuy

Lc, ra Sy, nung

Thy phn nhit 850C

Lm lnh

Lm lnh

Khuy

Hnh 13: Chu trnh iu chbt titan ioxit kch thc nano mt bin tnh N

bng tc nhn (NH4)2SO4 tTiCl4.


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Quy trnh iu chc tin hnh nhsau (Hnh 13): Pha dung dch hn hp

ru nc- mui (NH4)2SO4 theo t lxc nh. Lm lnh dung dch bng hn

hp mui n nhit 00C. Dng pipet nh tng git TiCl4 trong iu kin

khuy trn mnh. Qu trnh khuy v lm lnh c thc hin tip tc cho n khi

thu c dung dch trong sut.

Nng nhit ca dung dch n g trxc nh qu trnh thy phn xy ra.

Qu trnh thy phn c thc hin iu kin khuy trn mnh, nhit , thi

gian xc nh. Sau ly tm, tch pha rn khi pha lng. Pha rn c ra 2 ln

bng nc ct, 2 ln bng etanol v 2 ln bng nc ct. Sau em sy kh trong

tsy nhit v thi gian xc nh, sau em nung trong l nung nhit vthi gian thch hp thu sn phm. Sn phm c cn xc nh khi lng v

tnh hiu sut qu trnh iu ch, sau chp XRD xc nh thnh phn pha v

kch thc ht trung bnh, thquang xc tc xc nh hiu sut phn hy xanh

metylen, chp nh TEM bit c hnh nh chn thc ca ht.

2.2.2. Phng php thc nghim iu chbt titan ioxit kch thc nano mt

bin tnh N theo phng php tm tcht u l TiCl4

Cht u c sdng iu chbt TiO2l TiCl4 l loi sn phm ca Merck,

sch 99%. Kt ta TiO2.nH2O sdng lm cht u cho qu trnh bin tnh nit

c chun btheo quy trnh nhhnh 13.

Huyn ph TiO2.nH2O c chho vi dung dch NH3c nng khc nhau

trong 30 pht. Sau tch phn rn bng ly tm, sy kh trong t chn khng

Labtech (Hn Quc) 80OC trong 12h, nung trong l Nabertherm (Anh) nhit

xc nh, tc 100C/pht. Nghin sn phm trong ci m no.Gin XRD ca sn phm c ghi trn nhiu xkD8 Advanced Bruker

(CHLB c) vi anot Cu, khong ghi 2= 2070O, tc 0.03O/s. Thnh phn pha

ca sn phm c nhn din nhvtr v cng cc pic c trng trn gin

XRD. Kch thc ht trung bnh r(nm) ca tinh th titan ioxit c tnh theo

cng thc Debey Scherrer:


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- 38 -

0.89r

cos

=

(2.1)

Trong , r l kch thc ht trung bnh, nm; l bc sng K ca anot

bng ng, 0.154056 nm; l rng ca pic cc i ng vi na chiu cao(FWHM), radian; l gc nhiu xBragg ng vi pic cc i, .

Hnh 14:Chu trnh iu chbt titan ioxit kch thc nano mt bin tnh N

theo phng php tm tTiCl4.

Sc mt ca nittrong mu sn phm TiO2bin tnh c xc nh theo pic

c trng trn phEDS c ghi trn my Oxford 300 (Anh).

Hn hp ban uetanol/nc

Hn hp cha TiCl4

Dung dch trong sut

Huyn ph TiO2.nH2O

Khuy, trn mnh TiCl4nhtng git

Khuy

Thy phn nhit 90-950C

Lm lnh

Lm lnh

Khuy

Huyn ph TiO2.nH2Ochha vi dung dch

NH3

TiO2bin tnh Nit

Sy, nung

Ch ha vi dungdch NH3


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- 39 -

PHN III: KT QUV THO LUN

3.1. KHO ST KH NNG XC TC QUANG HA CA TiO2 LM

MT MU XANH METYLEN

kho st khnng xc tc quang ho cho qu trnh phn hucc cht hu

c trong dung dch nc chng ti kho st trn i tng l xanh metylen.

ng chun xc nh hiu sut phn hy xanh metylen xy dng c nhsau:

Lp ng chun:

Qu trnh lp ng chun phn tch nng xanh metylen trong nc

c tin hnh nhsau:

- Cn chnh xc 20 mg xanh metylen cho vo bnh nh mc 1 lt v nh mc

bng nc ct. Dung dch va pha c lm dung dch u cho qu trnh xy dng

ng chun.

- Ht ln lt 2.5 ml, 5 ml, 7.5 ml, 10 ml, 12.5 ml, 15 ml, 17.5 ml, 20 ml, 22.5

ml dung dch trn v nh mc thnh 100ml bng nc ct vo bnh nh mc 100

ml thu c cc dung dch c nng xanh metylen tng ng l 0.5 mg/l, 1.0

mg/l, 1.5 mg/l, 2.0 mg/l, 2.5 mg/l, 3.0 mg/l, 3.5 mg/l, 4.0 mg/l, 4.5 mg/l.

Tin hnh o mt quang ca cc dung dch va pha v thu c kt qu

nhsau:

Bng 3: Kt quo mt quang ca cc dung dchxanh metylen.

STT 1 2 3 4 5 6 7 8 9

Nng

xanh

metylen

(mg/l)

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

ABS 0.097 0.205 0.314 0.422 0.53 0.639 0.747 0.855 0.963


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- 40 -

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5

Nng xanh Metylen (g/l)

Mt

qu

ang(ABS)

Hnh 15: ng chun ca xanh metylen (y=0.2165x-0.00112).

Tthtrn hnh 15 c ththy rng, trong khong nng xanh metylen t

0.5mg/l n 4.5mg/l sphthuc ca mt quang vo nng xanh metylen l

bc 1, php o mt quang tun theo nh lut Lambe-Beer. V vy, th trn

hnh 14 c chng ti sdng lm ng chun cho php phn tch o quang xc

nh nng xanh metylen phc vcho mc ch nghin cu tip theo.

3.1.1. nh hng ca tllng TiO2/ nng xanh metylenTin hnh th nghim nhmc 2.3.2

Lng cc cht trong th nghim c chn nhsau:

mXanh metylen = 10 mg;

2TiOm =01.25 g ( r =12 nm).

Mu thu c sau th nghim c o mt quang bc sng 663 nm.

Kt quth nghim c nu ra bng 4 v hnh 16.T, thy rng:

- Khi c mt TiO2nng xanh metylen trong dung dch sau th nghim gim

rt nhiu.

- Khi lng TiO2tng th nng xanh metylen gim cng nhiu.


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- 41 -

Bng 4. Kt qukho st nh hng ca khi lng TiO2n khnng xc tc.

STT Khi lng

Xanh metylen (mg)/1l

Khi lng

TiO2(g)

ABS % xanh metylen

phn hu

1 10 0 3.379 0

2 10 0.25 1.774 47.48

3 10 0.50 1.026 69.64

4 10 0.75 0.708 79.05

5 10 1.00 0.549 83.76

6 10 1.25 0.523 84.51

0

20

40

60

80

100

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Khi lng TiO2 (g)

Phntrmphnhyxanhmetylen(%)

Hnh 16:nh hng ca lng 2TiO n khnng xc tc.

iu ny c gii thch nh sau: Khi khng c mt TiO2 dung dch xanh

metylen khng bmt mu do nh sng nhn thy khng c tc ng g trong vic

phn hy cht. Khi c mt TiO2di tc dng ca nh sng nhn thy c hot

ha v trthnh cht xc tc hot ng, n c khnng thc y qu trnh phn hy

xanh metylen (theo cch nu phn tng quan) do n to ra c cc gc t

do c khnng oxi ha mnh. Cc gc tdo c khnng oxi ha cc hp cht hu


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cto ra CO2, H2O hoc cc phn tn gin thcp. Khi lng TiO2tng n s

to c nhiu gc tdo c khoxi ha mnh lm cho dung dch xanh metylen mt

mu nhiu hn [14-15].

3.1.2. nh hng ca thi gian phn ng

Tin hnh th nghim nhmc 2.3.2.

Trong th nghim chng ti chn:

- mXanh metylen = 10 mg,

- mTiO2 = 0.75g (r=12nm).

- Thi gian phn ng thay i t60210 pht.

Kt quth nghim c nu ra trn bng 5 v hnh 17.

Bng 5. Kt qukho st thi gian phn ng.

STT

Khi lng

Xanh

metylen

(mg)/1l

Khi lng

TiO2 (g)

( r =12nm)

Thi gian

phn ng

(pht)

ABS

% Xanh

metylen

phn hu

1 10 0.75 60 1.521 55

2 10 0.75 90 1.362 59.7

3 10 0.75 120 0.916 72.9

4 10 0.75 150 0.551 83.7

5 10 0.75 180 0.470 86

6 10 0.75 210 0.429 87.3


44/90



- 43 -

30

50

70

90

110

25 50 75 100 125 150 175 200 225

Thi gian phn ng (pht)

Phntrmphnhyxan

hmetylen(%)

Hnh 17: nh hng ca thi gian phn ng n khnng xc tc.

T, thy rng: % xanh metylen phn hy tng khi thi gian phn ng tng.

Sau 210 pht th % xanh metylen phn hy t 91.2%.

Kt qu trn c gii thch nh sau: Khi thi gian phn ng cng lu th

lng TiO2cng c chiu sng nhiu, lm tng khnng to ra cc gc tdo c

khnng oxi ha mnh [14,15] dn n vic xanh metylen bphn hy cng nhiu.

3.1.3. nh hng ca nng xanh metylen

Th nghim c tin hnh nhmc 2.3.2

Lng cc cht trong th nghim c chn nhsau:

- mXanh metylen = 2.5-15 mg,

- mTiO2 = 0.75g (r=12nm).

Mu thu c sau th nghim c o mt quang bc sng 663 nm.

Kt quthu c nhbng 6 v trn hnh 18.T cho ta thy rng cng mt lng TiO2nhnhau v cc iu kin th

nghim nhnhau th lng xanh metylen cn li nhiu nu lng ban u l ln.


45/90



- 44 -

Bng 6. Kt qukho st nh hng ca nng xanh metylen.

STT Nng xanh

metylen(mg)/1l

Khi lng TiO2 (g)

( r =12 nm)

ABS % Xanh metylen

phn hu1 2.5 0.5 0.438 87.04

2 7.5 0.5 0.470 86.08

3 10 0.5 0.560 83.43

4 12.5 0.5 0.705 79.14

5 15 0.5 0.854 74.72

70

74

78

82

86

90

0 2.5 5 7.5 10 12.5 15 17.5

Nng xanh metylen (g/l)

Phntrmphnh

yxanhmetylen(%)

Hnh 18:nh hng ca nng xanh metylen.

iu ny c gii thch l khi cc iu kin th nghim nh nhau th cng

lng TiO2chc thto ra cc gc tdo c khnng oxi ha tng ng nhau,

nn n chlm phn hy c lng nht nh xanh metylen.

V vy, lng xanh metylen cn li sau th nghim tlthun vi lng xanh

metylen ban u.


46/90



- 45 -

Nhn xt: Nhvy bt TiO2c khnng xc tc quang ho, lm phn hu

xanh metylen vi hiu sut cao. Khnng xc tc ca TiO2phthuc vo cc iu

kin nh: lng cht xc tc, nng xanh metylen, thi gian phn ng ...

T cc th nghim trn ta rt ra kt lun, iu kin thch hp cho vic th

nghim khnng quang xc tc ca bt TiO2qua phn ng quang phn hy xanh

metylen l:

- Nng xanh metylen 10mg/1l;

- Khi lng cht xc tc: mTiO2 = 0.75g;

- Thi gian phn ng: 180 pht (3h).

Cc yu tny sc dng thhot tnh quang xc tc ca cc mu titanioxit bin tnh iu chc.

3.2. IU CH BT TITAN IOXIT KCH THC NM BIN TNH N

BNG TC NHN (NH4)2SO4THEO PHNG PHP THY PHN TiCl4

3.2.1. nh hng ca nng Ti4+trong dung dch khi thuphn

Qu trnh thc nghim c tin hnh nh nu mc 2.2.1.

Trong th nghim ny chng ti chn:

+ Tlca etanol/ nc l 20% vthtch v nng (NH4)2SO4l 30(g/l)

+ Nhit qu trnh thuphn c duy tr 850C.

+ Nng TiCl4thay i t4TiCl

0.29 1.28M(V 0.5 2.5ml) = .

+ Nng xanh metylen ban u: 10mg/l; mTiO2 = 0.75g; thi gian chiu nh

sng n Compact cng sut 40W l 3h.

Sau khi thuphn, kt ta c li tm, ra bng nc ct hai ln, ra bng

etanol hai ln sau ra li bng nc ct hai ln, sy trong tsy chn khng

800C trong 24h, nung 5000C trong 1h. Sn phm iu chc cn khi lng

tnh hiu sut iu ch, c ghi ph XRD xc nh thnh phn pha v kch

thc ht trung bnh, em thquang xc tc kho st khnng quang xc tc.


47/90



- 46 -

Cc kt qu thc nghim c a ra bng 7 v cc hnh 19-22. T, c th

thy rng:

- Cc mu sn phm TiO2iu chc u dng tinh thanatase dng bt

c kch thc ht trung bnh 10 nm.

- Hiu sut qu trnh iu ch kh cao chng t qu trnh thu phn xy ra

hon ton.

- Nng c nh hng ng kn kch thc ht trung bnh. Khi nng

TiCl4tng t0.291.28 mol/l th kch thc ht gim sau li tng, c im cc

tiu nng TiCl4 bng 0.81M.

Hnh 19: PhXRD ca mu sn phm bt TiO2

thu c nng TiCl4bng 0.81 mol/l.


48/90



- 47 -

Hnh 20: PhXRD ca mu c kho st cc nng khc nhau ca

TiCl4: 1-0.29M, 2-0.56M, 3-0.81M, 4-1.05M, 5-1.28M.

Bng 7. Kt qukho st nh hng ca nng cht u TiCl4(mol/l) n

kch thc ht trung bnh(nm).

STT Nng TiCl4( mol/l) r( nm) Hiu sut phn

hy xanh

metylen, %

Hiu sut( %)

1 0.29 10.5 54 86.5

2 0.56 7.7 65.67 89.2

3 0.81 6.2 82.71 98.7

4 1.05 9.8 73.11 92.7

5 1.28 11.3 59.06 88.9

2

1

4

3

5


49/90



- 48 -

4

6

8

10

12

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Nng TiCl4 (mol/l)

Kchthchttrung

bnh(nm)

Hnh 21:nh hng ca nng TiCl4(mol/l)n kch thc

ht trung bnh (nm).

40

50

60

70

80

90

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Nng Ti4+ (mol/l)

Phntrmphnhyxanhm

etylen(%)

Hnh 22:nh hng ca nng TiCl4(mol/l)n % phn hy xanh metylen.

Kt qu trn c gii thch nh sau: vng nng TiCl4 (0.81M) khi

tng nng TiCl4 th s thuphn dung dch TiCl4 cng tng, lc tc to


50/90



- 49 -

mm tinh th tng, tc pht trin mm cha tng mnh. Do kch thc ht

trung bnh ca TiO2gim khi tng nng TiCl4 [14,18, 24]. Khi nng TiCl4ln

hn (>0.81M) cc sn phm thy phn trong dung dch c to ra nhiu nn c l

c s chuyn i tu tin qu trnh to mm sang qu trnh pht trin mm khi

lng mu trong dung dch nhiu, do tc pht trin mm li tng ln.

Dn n kch thc ht trung bnh ca cc ht TiO2 tng khi tng nng TiCl4.

ng thi vi sgim kch thc ht th phn trm phn hy xanh metylen tng ln

v t cc i khi nng t 0.80 mol/l. Mi quan h gia nng TiCl4 v

phn trm phn hy xanh metylen c biu din bng mt ng cong nhn. iu

ny do khi N c a vo vi lng ph hp, n sxm nhp vo mng li caTiO2v lm tng khnng phn hy xanh metylen di nh sng nhn thy [38-40].

Nu lng N l ln th mt phn snm trn bmt ca TiO2v lm gim khnng

phn hy xanh metylen.

Hnh 23:nh TEM ca mu TiO2bin tnh N (bng tc nhn (NH4)2SO4 theo

phng php thy phn) vi nng TiCl40.81 mol/l.

Nhvy, theo chng ti nng TiCl4 thch hp c khnng quang xc

tc cao l t0.70.9 mol/l v tt nht l 0.80 mol/l. Chng ti chn nng TiCl4


51/90



- 50 -

ny kho st cc nh hng ca cc thnh phn khc trong dung dch khi thu

phn TiCl4.

3.2.2. Kho st nh hng ca (NH4)2SO4trong dung dch khi thy phnQu trnh thc nghim c tin hnh nh nu mc 2.2.1.


+ Tlca etanol/ nc l 20% vthtch.

+ Nng (NH4)2SO4l thay i t15-35(g/l)

+ Nhit qu trnh thuphn c duy tr 850C.

+ Nng TiCl4l 0.8mol/l.

+ Nng xanh metylen ban u: 10mg/l; mTiO2 = 0.75g; thi gian chiu nh






thc ht trung bnh, em thquang xc tc kho st khnng quang xc tc.Cc kt quthc nghim c nu bng 8 v hnh 24, 25.

Bng 8. Kt qukho st nh hng ca nng (NH4)2SO4(g/l)

n kch thc ht trung bnh (nm).

STTNng

4 2 4(NH ) SO (g/l)r( nm)

% phn hy

xanh metylenHiu sut (%)

1 15 14.5 55.24 90.2

2 20 6.4 67.75 93.3

3 25 5.8 79.13 94.0

4 30 6.2 80.56 92.5

5 35 6.1 81.27 89.4


52/90



- 51 -

Hnh 24: PhXRD ca cc mu vi lng (NH4)2SO4khc nhauNng (NH4)2SO4(1-15g/l, 2-20g/l, 3-25g/l, 4-30g/l, 5-35g/l).

Lin(Cps)

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

20 30 40 50 60 7

d=3.2

50

d=2.4

88

d=2.2

91

d

=2.1

87

d=2.0

55

d=1.6

87

d=1.6

24

d=1.3

45

d=1.4

79

d=1.4

53

d=1.3

60

Hnh 25: PhXRD ca mu khng c (NH4)2SO4.

2

1

4

3

5


53/90



- 52 -

4

6

8

10

12

14

16

10 20 30 40

Nng (NH4)2SO4 (g/l)

Kchthch

ttrun

gbnh(nm)

Hnh 26:nh hng ca nng (NH4)2SO4(g/l)

n kch thc ht trung bnh (nm).

40

50

60

70

80

90

10 15 20 25 30 35 40

Nng (NH4)2SO4(g/l)

Ph

ntrmphnhyxanh

metylen(nm)

Hnh 27:nh hng ca nng (NH4)2SO4(g/l)

n % phn hy xanh metylen.

T, c th thy rng sc mt ca (NH4)2SO4 c nh hng rt ln n

kch thc ht v cu trc tinh thca TiO2. Theo nhcc ti liu th nh hng

ca (NH4)2SO4l do ion24SO . Tc dng ca ion 24SO

l lm gim kch thc ht


54/90



- 53 -

(gim t14.5 nm xung n 5.8 nm). Kt qutrn c gii thch l do ion 24SO v

ion NH4+vi kch thc ln hn schim u thtrong qu trnh hp phln cc ht

TiO2. Kt ta hp ph ion sunfat gy ra tnh knc n gy ra lc y tnh intrnh c skeo tgia cc ht vi nhau v to ra cc ht TiO2kch thc cc

mn. C ch c l l do ion 2-4SO gy ra s pht trin cc chm TiO2 thnh dng

anatase, lm tng din tch bmt to ra mng li xp dn n khnng quang

xc tc cng cao hn. Nhng khi thay i nng (NH4)2SO4 t 25-35 g/l th

khng gy nh hng r rt n kh nng quang xc tc do khi tng nng

(NH4)2SO4 c slp y ltrng trong mng li ca TiO2, c lin quan n mc

bo ha ca qu trnh thm nhp N vo TiO2 [38-40]. T hnh 24, 25 ta thy

rng khi khng c mt ion (NH4)2SO4 th trn ph XRD ca mu xut hin pha

rutile ngay khi chnung mu 5000C trong 2h, cn khi c mt ion (NH4)2SO4 th

trn phXRD ca mu chxut hin pha anatase. iu ny c gii thch l do

(NH4)2SO4 c tc dng lm bn pha anatase [43-44].

Hiu sut qu trnh iu ch l kh cao, chng t qu trnh iu ch xy ra

hon ton. Hiu sut iu ch thay i khng ng k khi thay i lng

(NH4)2SO4.

Theo chng ti, c th to ra bt TiO2 bin tnh N bng (NH4)2SO4 theo

phng php thy phn TiCl4c kch thc l nhnht, khnng xc tc quang tt

nht th nng (NH4)2SO4ti u t25-35g/l. Chng ti dng nng (NH4)2SO4

l 30g/l kho st cc yu ttip theo.

3.2.3. Kho st sc mt ca ru etylic


Trong th ngim ny chng ti chn:

+4TiCl

V =2ml, nng (NH4)2SO4l 30 g/l, nhit qu trnh thy phn

c duy tr 850C.

+2 5 2C H OH H O

V :V trong dung dch thuphn c thay i t0 1.5.


55/90



- 54 -

+ Nng xanh metylen ban u: 10 mg/l; mTiO2 = 0.75 g; thi gian chiu nh







Kt quthc nghim c a ra trn bng 9 v cc hnh 28-30.

Hnh 28: PhXRD ca cc mu vi tl2 5 2

/C H OH H O

V V khc nhau.

1-0, 2-0.11, 3-0.25, 4-0.43, 5-0.66, 6-1.00, 7-1.5.

3

2

1

5

4

6

7


56/90



- 55 -

Bng 9. nh hng ca tletanol/ nc n kch thc ht trung bnh,

phn trm phn hy xanh metylen.

Dung mi r (nm) % phn hyxanh

metylen

Hiu sut(%)

STT 4TiClV(ml)

2H OV (ml)

2 5C H OHV (ml)

1 2 20 0 8.51 80.01 97.33

2 2 18 2 5.93 81.03 98.00

3 2 16 4 6.20 81.87 91.00

4 2 14 6 6.28 69.84 90.20

5 2 12 8 6.87 68.12 89.00

6 2 10 10 8.30 68.08 89.40

7 2 8 12 10.60 67.59 84.00

60

65

70

75

80

85

0 0.25 0.5 0.75 1 1.25 1.5 1.75

Tletanol/nc

Phntrmphnhyxanhmetylen(%)

Hnh 29:nh hng ca tletanol/ nc n phn trm phn hy xanh metylen.


57/90



- 56 -

4

5

6

7

8

9

10

11

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

T letanol/nc

Kchthch

ttrun

gbnh(nm)

Hnh 30:nh hng ca tletanol/ nc n kch thc ht trung bnh.

T, c ththy rng:

+ Hiu sut phn hy xanh metylen t gi tr cao khi t l th tch etanol/

nc t00.25.

+ Kch thc ht trung bnh ca 2TiO thu c khi c mt etanol l rt b

(khong 59 nm).

+ Hiu sut qu trnh iu ch cao chng tphn ng xy ra gn nh hon

ton.

+ Cc mu thu c u dng tinh thanatase.

Kt qutrn c gii thch nhsau: Phn tetanol c phn cc km hn

nc, nn khi thm etanol vo dung dch slm gim phn cc ca dung mi, v

vy slm gim tc thuphn, dn n tc to mm tinh thgim. V vy,

ni chung khi tng nng etanol th kch thc ht stng. Tuy nhin, theo thc

nghim cho thy vng nng etanol thp (t l th tch etanol/nc bng 0

0.25) c sgim kch thc kh r rt ng thi hiu sut phn hy xanh metylen

trong khong tlny cng cao hn. Theo chng ti, c lsc mt ca etanol

vng nng thp s lm cho 4TiCl phn tn tt hn trong mi trng lng khi


58/90



- 57 -

thu phn, do 4TiCl c th to thnh cc hp cht trung gian kiu etoxit

x 2 5 4 x(TiCl (OC H ) ) , nhcc tc gi [43] nu. Chnh iu ny s to iu kin

cho qu trnh thuphn ng u hn, trnh c hin tng thuphn cc b, vlm cho N c thphn tn tt vo 2TiO . Khi t letanol/nc tng vt qu 0.25

th vic tng tletanol slm gim lng nc trong dung dch do lm gim

tc qu trnh thuphn, tc to mm gim cn tc pht trin mm tng

lm cho kch thc ht tng.

Khnng quang quang xc tc cao nht ti vng tl th tch C2H5OH/H2O

trong khong 0.110.25. T l ny c s dng trong cc th nghim thuphn

tip theo.

Hnh 31:nh TEM ca mu vi tlthtch etanol/nc l 0.25.

3.2.4. nh hng ca nhit thy phn



+4 4 2 4 2 5 2TiCl (NH ) SO C H OH H O

n : n : n : n 1:10 :1.28 : 58.06= theo t l mol, tng

thtch ca dung dch l 16.5 ml.


59/90



- 58 -

+ Nhit qu trnh thuphn c duy tr trong khong 550C1050C.








Hnh 32: PhXRD ca cc mu c thy phn cc nhit khc nhau

1-550C, 2-650C, 3-750C, 4-850C, 5-950C, 6-1050C.

Bng 10. nh hng ca nhit thy phn n kch thc ht trung bnh

v phn trm phn hy xanh metylen.

STT Nhit (oC) r(nm) % phn hy

xanh metylen

Hiu sut

(%)

1 55 8.6 60.08 85.3

2 65 6.1 67.04 94.2

3 75 6.2 77.85 93.0

4 85 6.9 84.2 95.5

5 95 7.9 73.4 92.4

6 105 8.4 69.9 95.7

2

1

4

3

56


60/90



- 59 -

5

6

7

8

9

40 50 60 70 80 90 100 110

Nhit thy phn (0C)

Kchthch

ttrun

gbnh(nm)

Hnh 33:nh hng ca nhit thuphn

n kch thc ht trung bnh.

50

60

70

80

90

40 50 60 70 80 90 100 110

Nhit thy phn (0C)

Phntrmphnhyxanh

metylen(%)

Hnh 34:nh hng ca nhit thuphn n phn trm

phn hy xanh metylen.

Tbng 10 v hnh 33, 34 ta thy:

+ Nhit thuphn c nh hng r rt n kch thc ht trung bnh. Kch


61/90



- 60 -

thc ht trung bnh ca cc mu TiO2u b < 10nm.

+ Hiu sut qu trnh iu chkh cao chng tqu trnh thuphn TiCl4

xy ra hon ton.

+ Nhit thuphn c nh hng n phn trm phn hy xanh metylen.

Ta nhn thy hiu sut phn hy xanh metylen t gi trcao khi nhit thy phn

l t80-900C, t cc i ti 850C.

Kt qutrn c gii thch nhsau: Trong qu trnh thuphn TiCl4to

ra TiO2, c hai qu trnh xy ra ng thi xy ra, l qu trnh to mm v qu

trnh pht trin mm. Khi tng nhit thuphn th tc thuphn tng ln, do

tc to mm tinh thv qu trnh qu bo ha dung dch tng v s lngmm tinh th tng, N ddng thm nhp vo mng li tinh thca TiO2v lm

cho kch thc ht trung bnh b i, c s thay i v thnh phn pha. Tuy nhin

khi nhit tng th tc pht trin mm cng tng lm cho kch thc ht trung

bnh tng ln ng thi N kh thm nhp vo mng li tinh thca TiO2. Hai qu

trnh ny c nh hng ngc chiu nhau ln kch thc ht trung bnh v khnng

quang xc tc ca TiO2[4-6, 38-43].

Ti nhit ca mi trng thuphn t 70-900C, kch thc ht trung bnh

tng i nhv phn trm xanh metylen mt mu l cc i. Khi nhit thu

phn tng cao hn na (> 900C) th qu trnh pht trin ht chim u thdo kch

thc ht stng, hiu sut phn hy xanh metylen gim khi nhit tng. Chng

ti schn nhit thy phn l 850C cho cc th nghim tip theo.

3.2.5. Kho st thi gian lu mu trc ly tm

Qu trnh thc nghim nh nu mc 2.2.1.

Trong th ngim ny chng ti chn:

+4TiCl

V 10ml= , nng (NH4)2SO4l 30 g/l, tletanol/nc l 20% vth

tch, nhit thuphn c duy tr 850C.




62/90



- 61 -

Kt ta thu chia thnh cc phn tng ng ri lu mu cc thi gian khc

nhau, sau kt ta c li tm, ra bng nc ct hai ln, ra bng etanol hai ln

sau ra li bng nc ct hai ln, sy trong tsy chn khng 800C trong 24h,

nung 5000C trong 1h.

Sn phm iu chc cn khi lng tnh hiu sut iu ch, c ghi

phXRD xc nh thnh phn pha v kch thc ht trung bnh, em thquang

xc tc kho st khnng quang xc tc. Kt quthu c thhin trn hnh 35,

36 v bng 11.

Hnh 35: PhXRD ca cc mu vi thi gian lu mu

trc ly tm khc nhau

1-0h, 2-24h, 3-48h, 4-72h, 5-96h, 6-120h.

2

1

4

3

5

6


63/90



- 62 -

Bng 11. Kt qukho st nh hng ca thi gian lu mu (h) n kch

thc ht trung bnh (nm).

Dung miTT 4

TiClV

(ml)

2H OV (ml)

2 5C H OHV (ml)

Thigian

lu

mu

(h)

r

(nm)

% phn

hy

xanh

metylen

Hiu

sut

(%)

1 10 100 20 0 8.60 82.03

2 10 100 20 24 9.88 79.20

3 10 100 20 48 11.05 78.12

4 10 100 20 72 11.10 67.14

5 10 100 20 96 11.20 65.34

92

8

9

10

11

12

0 20 40 60 80 100 120

Thi gian lu mu (h)

Kchthch

ttrungbnh(nm)

Hnh 36:nh hng ca kch thc ht trung bnh vo thi gian lu mu.


64/90



- 63 -

50

55

60

65

70

75

80

85

0 20 40 60 80 100 120

Thi gian lu mu (h)

Phntrmphnhyxanh

metylen(%)

Hnh 37: nh hng ca phn trm phn hy xanh metylen vo thi gian lu mu.

T thy rng:

+ Kch thc ht scp tng t8.611.44 nm khi thi gian lu mu tng t

0120 h. Mu thu c dng anatase v c kch thc tng i nh(


65/90



- 64 -

- Nng NH3dng chho huyn ph TiO2.nH2O thay i t10-4M

n 2M.

Cc gin XRD v phn tch nhit ca mu sn phm bt TiO2 c ch

ho vi dung dch NH30.6M c a ra trn cc hnh 38, 39:

M a u 2 , 6 - 0 ,6 M

0 0 - 0 0 4 - 0 4 7 7 ( D ) - A n a t a s e , s yn - T i O 2 - Y : 6 0 . 9 4 % - d x b y : 1 . - W L : 1 . 5 4 0 6 - T e t r a g o n a l - a 3 . 7 8 3 0 0 - b 3 . 7 8 3 0 0 - c 9 . 5 1 0 0 0 - a l p h a 9 0 . 0 0 0 - b e t a 9 0 . 0 0 0 - g a m m a 9 0 . 0 0 0 - B o d y - c e n t e r e d - I 4 1 / a m d ( 1 4 1 ) -

0 0 - 0 2 1 - 1 2 7 6 ( * ) - R u t il e , s y n - T i O 2 - Y : 7 9 . 5 6 % - d x b y : 1 . - W L : 1 . 5 4 0 6 - T e t r a g o n a l - a 4 . 5 9 3 3 0 - b 4 . 5 9 3 3 0 - c 2 . 9 5 9 2 0 - a l p h a 9 0 . 0 0 0 - b e t a 9 0 . 0 0 0 - g a m m a 9 0 . 0 0 0 - P r i m i t iv e - P 4 2 / m n m ( 1 3 6 ) - 2 - 6 2 . 4

2)

1)

F i le : L i e n m a u 2 , 6 - 0 , 6 M . ra w - T y p e : L o c k e d C o u p l e d - S t a r t : 2 0 . 0 0 0 - E n d : 7 0 . 0 1 0 - S t e p : 0 . 0 3 0 - S t e p t i m e : 1 . s - T e m p . : 2 5 C ( R o o m ) - T i m e S t a r t e d : 5 s - 2 - T h e t a : 2 0 . 0 0 0 - T h e t a : 1 0 . 0 0 0 - C h i : 0 . 0

L e f t A n g l e : 2 6 . 5 4 0 - R i g h t A n g le : 2 8 . 4 3 0 - L e f t I n t . : 2 . 0 0 C p s - R i g h t I n t . : 2 . 00 C p s - O b s . M a x : 2 7 . 4 4 0 - d ( O b s . M a x ) : 3 . 2 4 8 - M a x I n t . : 2 1 1 C p s - N e t H e i g h t : 2 0 9 C p s - F W H M : 0 . 4 7 3 - C h o r d M i d . : 2

L e f t A n g l e : 2 4 . 3 2 0 - R i g h t A n g le : 2 5 . 9 7 0 - L e f t I n t . : 2 . 0 0 C p s - R i g h t I n t . : 2 . 00 C p s - O b s . M a x : 2 5 . 2 9 9 - d ( O b s . M a x ) : 3 . 5 1 8 - M a x I n t . : 1 8 0 C p s - N e t H e i g h t : 1 7 8 C p s - F W H M : 0 . 4 1 1 - C h o r d M i d . : 2

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Luan Van Giang Full 2521

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