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Applied Surface Science 257 (2011) 8850–8856

Contents lists available at ScienceDirect

Applied Surface Science

 journal homepage: www.elsevier .com/ locate /apsusc

The potential use of nanosilver-decorated titanium dioxide nanofibers for toxin

decomposition with antimicrobial and self-cleaning properties

Chutima Srisitthiratkul, Voraluck Pongsorrarith, Narupol Intasanta∗

National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 130 Thailand Science Park, Phahonyothin Road, Klong Luang,

Pathumthani 12120, Thailand

a r t i c l e i n f o

 Article history:

Received 29 December 2010Receivedin revised form 18 April 2011

Accepted 18 April 2011

Available online 12 June 2011

Keywords:

Titanium dioxide

Nanofibers

Electrospinning

Silver

Nanoparticles

 Japan Industrial Standard (JIS)

Nitrogen oxide

Volatile organic compound (VOC)

Staphylococcus aureus

Escherichia coli

Wetting

SuperhydrophilicitySelf cleaning

a b s t r a c t

While chemical and biological attacks pose risk to human health, clean air isof scientific, environmental

and physiological concerns. In the present contribution, the potential use of nanosilver-decorated tita-

nium dioxide (TiO2) nanofibers for toxin decomposition with antimicrobial activity and self-cleaning

properties was investigated. Titanium dioxide nanofibers were prepared through sol–gel reaction

followed byan electrospinning process. Following the Japan Industrial Standard (JIS) protocol, decompo-

sitions of nitrogen oxide (NOx) and volatile organic compound (VOC) by the TiO2  nanofibers suggested

that these materials were capable of air treatment. To further enhance their anti-microbial activity, silver

nanoparticles were decorated onto the TiO2   nanofibers’ surfaces via photoreduction of silver ion in the

presence of the nanofibers suspension. Furthermore, tests of photocatalytic activity of the samples were

performed by photodegradingmethyleneblue in water. The nanofibrousmembranesprepared from these

nanofibers showed superhydrophilicity under UV. Finally, the possibility of using these hybrid nanofibers

in environmental and hygienic nanofiltration was proposed, where the self-cleaning characteristics was

expected to be valuable in maintenance processes.

© 2011 Elsevier B.V. All rights reserved.

1. Introduction

Clean air is of scientific, environmental and health concerns

[1,2]. Both chemical [3,4] and biological[5] contaminants pose risks

to both industrial settings and household. Nitrogen oxide (NOx)

[4] and volatile organic compounds (VOCs) [3] are among com-

mon noxious byproducts from transportation and manufacturing.

In addition, bacteria and virus have been the pinpoint of physio-

logical apprehension in recent times [5]. In general, antimicrobial

proteins in the pulmonary systems constitute to our physiolog-

ical defense mechanism [6]. However, recent reports on effectsof airborne chemical and biological pollutions on human health

[4,5] implied that more effective protection systems are still highly

sought after.

Degradation of chemical pollutions [7–9] and biological dis-

infection [10,11] has been proven possible with photocatalysis.

Photocatalysts harvest light as an energy source to excite elec-

∗ Correspondingauthor. Tel.: +66 2564 7100x6580; fax: +66 25646981.

E-mail address: narupol@nanotec.or.th(N. Intasanta).

URL: http://www.nanotec.or.th (N. Intasanta).

trons from valence to conduction bands [12,13]. The generated

electrons and holes make possible reductive and oxidative reac-

tions of organic pollutant into carbon dioxide and water. Titanium

dioxide (TiO2), a metal-oxide semiconductor, has been studied and

widelyused as a photocatalytic material owing to itsrelatively high

photocatalytic activity, chemical stability, non-hazardous nature,

superhydrophilic property and antibacterial activity [13,14]. The

TiO2 photocatalyst which is driven by the clean energy of sunlight

is expected to be applied in many potential applications such as

self-cleaning [15–18], degradation of organic pollutants [19–22],

photoelectrode and electrochromic device [23–26].Due to their high surface area and unique properties, the use of 

nanomaterials has gained tremendous attention in both industrial

and academic arena. In photocatalysis, exploitation of nanoma-

terials involves some limitation which depends strongly on their

dimension. Spherical-shaped nanomaterials inherit practical prob-

lemsrelatingto self-agglomeration [27,28]which lead to lowactive

surface area and, thus, low efficiency. In contrast, one-dimensional

materials such as nanofibers show much less agglomeration.

As such, electrospinning is a facile and cost-effective route to

generate fibers with diameters at nanometer length scale [29–32].

As a typical approach, metal alkoxides are used as precursors for

0169-4332/$ – see front matter © 2011 Elsevier B.V. All rights reserved.

doi:10.1016/j.apsusc.2011.04.083

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the syntheses of several semiconductor nanofiber such as tita-

nium dioxide [13,14]. Variation of solution properties and spinning

parameters leads to a wide range of one-dimensional nanostruc-

tures ranging from single to multi-componentnanofibers [33]. As a

consequence, this technique has been exploited for medical, mate-

rial and energy applications [13,14].

In the present contribution, TiO2   nanofibers were prepared

through sol–gel reaction and electrospinning process [29–32]. The

potentialuse of these nanofibersas airnanofilters wasshownin the

decompositions of nitrogen oxide (NOx) and volatile organic com-

pound (VOC) under Japan Industrial Standard (JIS) protocol[34]. To

further enhance their anti-microbial activity, silver nanoparticles

were decorated onto the nanofibers’ surfaces by photoreduction

[35–38]. In so doing, aqueous-base photoreduction of silver ion

in the presence of nanofiber suspension resulted in nanosilver-

decorated TiO2   nanofibers. Furthermore, tests of photocatalytic

activity of the samples were performed by photodegrading methy-

lene blue in water. The nanofibrous membranes prepared from

these nanofibers showed superhydrophilicity under UV. Finally,

the possibility of using these hybrid nanofibers in environmental

and hygienic nanofiltration was proposed, where the self-cleaning

characteristics was expected to be valuable in maintenance pro-

cesses.

2. Experimental

 2.1. Chemicals

Titanium (IV) isopropoxide (TiP, 97%, Aldrich), P25 (Degussa,

Germany), hydrochloric acid (HCl, 37%, Carlo Erba), ethanol

(C2H5OH, 99.8%, Carlo Erba), polyvinylpyrrolidone (PVP,

M w  ∼ 360,000, Fluka), pluronic (M w  ∼ 5800, Aldrich) and silver

nitrate (AgNO3, Aldrich) were used as received.

 2.2. Preparation of titanium dioxide nanofibers

Titanium nanofibers were prepared by an electrospinning pro-

cess [29–32,39]. The precursor gel for electrospinning titaniumdioxides nanofibers was prepared using titanium (IV) isopropox-

ide, hydrochloric acid, ethanol, polyvinylpyrrolidone and pluronic.

In the synthetic procedure, 0.5g of pluronic and 0.5g of PVP were

firstly dissolved in 7 g of ethanol under magnetic stirring. In a sep-

arate beaker, a TiO2  sol was prepared by adding 3.56g of TiP into

a mixture of 2g of ethanol and 0.25ml of HCl. Then, this solution

was mixed with the PVP–pluronic solution followed by magnetic

stirring at room temperature for 15min. The resulting precursor

gel was heated at 50◦C for 24 h.

In the electrospinning set up, the precursor gel was loaded into

a 3 ml polypropylene syringe barrel, equipped with a 21-guage,

stainless steel, flat tip needle connected to a high-voltage supply

(Spellman, USA). During the process, the solution was fed at a con-

stant rate of 0.3ml/h by a syringe pump (Vernon Hills, USA). Anelectrical potential of 10kV was then applied between the tip of 

the needle and the grounded aluminum foil target which were

15cm apart. The as-spun nanofibers were calcined at 500 ◦C f o r 4 h

under air in order to remove organic contents and form crystalline

titanium dioxide.

 2.3. Preparation of nanosilver-decorated titanium dioxide

nanofibers

Deposition of nanosilver onto the surfaces of titanium dioxide

nanofibers was performed by a facile and cost-effective photo-

chemical reaction [35]. The following protocol is given as an

example. Firstly, 60mg of calcined titanium dioxide nanofibers

were dispersed in 60ml deionized water and sonicated for 10min.

Immediately afterward, 0.6 mg of silver nitrate was added and the

solution was magnetically stirred for 10min. Then UV irradiation

at 365nm was applied onto the solution under magnetic stirring

for another 1 h. The resulting dark dispersion was filtered, washed

and dried before further characterization. Different amounts – 2,

5 and 10wt.% – of silver were deposited onto titanium dioxide

nanofibersby varying silvernitratecontentfrom1.2,3.0and 6.0mg,

respectively.

 2.4. Preparation of nanofibrous layers for gas-phase

 photocatalytic and contact angle measurement 

Nanofibrous layers were prepared for gas-phase photocatalytic

and contact angle measurements. In a typical protocol, 200 mg of 

titanium dioxide nanofibers were dispersed in 2 ml of deionized

water and sonicated for 5 min. Then, the resulting dispersion was

spreadover a 5 cm×10cm glass slide before drying at 70◦Cfor1 h.

As a reference, P25 layer was prepared with the same method.

3. Characterization and instrumentation

 3.1. X-ray diffraction

The crystal structures presented in the titanium dioxide

nanofibers were determined by powder X-ray diffraction or XRD

method. The measurements were carried out with JOEL, JDX-3530,

2 kW instrument at room temperature with CuK   as the irradi-

ation source. The patterns were recorded over the angular range

of 15–80◦ (2 ), using scan rate of 0.02◦/min. The average size of 

nanosilver decorating on the fibers was calculated from FWHM

using Program MDI Jade 6.5.

 3.2. Electron microscopy

The nanofibers’ morphologies were characterized by scanning

electron microscope (SEM, S3400N, Japan) and transmission elec-

tron microscope (TEM, JEOL JEM-2010). The spatial distribution of silver element and nanosilver was determined from SEM under

elemental mapping mode.

 3.3. Decomposition of model toxin

The decompositionsof nitrogen oxide(NOx) andvolatileorganic

compound (VOC) followed Japan Industrial Standard (JIS) protocol

[34,40,41]. In a typical protocol,100 mg of activematerials wasson-

icated in 2 ml deionizedwater. The resulting slurrywas coated on a

5 cm×10cm glass substrate. The concentration of active materials

was 2 mg/cm2. The experiment was conducted at AIST, Japan.

 3.4. Photoluminescence

Photoluminescence was measured at room temperature with

Perkin Elmer LS-55 Fluorescence Spectrometer using a high energy

pulsed xenon source for excitation.

 3.5. Photocatalytic activities

The photocatalytic activities of the samples were performed

against degradation of methylene blue, using 300W high-pressure

Hg lamp UV source. Methylene blue has been used widely as a

standard model contaminant for photocatalysis [42]. Before the

photoreaction, 10 mg of the prepared nanofibers was dispersed in

20ml of 5ppm methylene blue solution for 10min using ultra-

sonicator (Crest, Malaysia). The suspension was kept in the dark

and continuously magnetically stirred for 30min to equilibrate the

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adsorption–desorption processes [42]. Subsequently, the result-

ing suspension was illuminated with UV under magnetic stirring.

The distance between the UV source and the reaction containers

was fixed at 10 cm. After every given interval of UV irradiation,

a 1 ml aliquot of the sample was collected, centrifuged and fil-

tered to remove the photocatalyst. The concentration of methylene

blue was measured with UV-Vis spectrophotometer (Perkin Elmer,

Lambda 650, USA) at 663 nm, the maximum absorption of methy-

lene blue.

 3.6. Antibacterial activities

Antibacterial activities of samples were examined by agar diffu-

sion method [43–45], where Staphylococcus aureus (S. aureus, ATCC

6538) and Escherichia coli (E. coli, ATCC 25922) were utilized as

Grampositive and Gramnegative bacterial strains, respectively. An

antimicrobial agent was utilized as a positive control. On each test-

ing plate,three small dishes containing similar samplewere placed

in close proximity. Another dish containing antibacterial agent was

placed towards the upperarea. Lackof inhibitory zonesimpliedthat

therewere no antibacterial activities. Formationof inhibitoryzones

entailed antibacterial activities. Zones of inhibition were averaged

from the three small dishes on the same testing plate.

 3.7. Contact angle measurements

Contact angle measurements were performed using Tensiome-

ter with water as a probe liquid (Dataphysics Instruments, TC/TPC

150). A water droplet was placed onto the surface of a nanofibrous

membrane.Staticcontact angleswere thenmeasured.Six measure-

ments were made on different areas and the average values were

reported.

4. Results and discussion

Electrospinning was chosen to fabricate TiO2  nanofibers from

titanium alkoxide precursor containing PVP as a polymer additive.This facile approach gave rise to organic–inorganic nanofibers with

diameter at nanometer length scale. To complete the hydrolysis,

condensation and elimination of all the organic components, calci-

nation was applied. The physical characteristics of the TiO2  fibers

after calcination at 500◦C were unveiled by SEM. Fig. 1a shows an

SEM micrograph of the resulting TiO2 nanofibers. These nanofibers

appeared smooth with diameters of about 200–300nm which

were quantitatively evaluated using their high-magnification SEM

images. Afterthe preparation of nanofibrous layers, whichincluded

grinding the catalyst, the nanofibers became broken with their

average length decreased to about 5m. As shown in Fig. 1b, the

layer was not only fibrous but also highly porous. As evident, the

fiberswere fullydispersed in thelayer. This characteristic wasquite

the opposite from most of spherical-shaped nanomaterials whichtended to agglomerate. Self-agglomeration of photocatalytic nano-

materials might lead to a decrease in accessible active surface and,

thus, their efficiencies.

The potential use of these nanofibers as air nanofilters was

shown in the decompositions of nitrogen oxide (NOx) and volatile

organic compound (VOC) under Japan Industrial Standard (JIS) pro-

tocol. Japanese Industrial Standards (JIS), stipulated the standards

employed for procedures in Japanese industries. The standard-

ization progression has been synchronized by Japanese Industrial

Standards Committee. JIS has been adopted widely in academia and

industries [34,40,41]. From JIS R 1701-3:2008, Toluene, a common

noxious solvent extensively used in industries, wasused as a model

toxin for VOC decomposition measurement. Similarly, JIS R 1701-

1:2010 or ISO 22197-1:2007 exploited NOx to represent harmful

Fig. 1. Physical characteristics of photocatalyst nanofibers. (a) SEM micrograph of 

electrospun TiO2  nanofibers. (b)SEM image of TiO2  nanofiber coated substrate.

gaseous byproducts from industrial productions and transporta-

tion. The detailed mechanism of photocatalytic decomposition of 

VOC and NOx were described elsewhere [46–48]. Briefly, the pho-

tocatalysis of toluene and NOx mainly resulted in carbon dioxide

and HNO3, respectively.

From Fig. 2a and b, titanium nanofibrous membrane showed

21% and 30% removal for NOx and toluene, respectively. Com-

parison with literature data has been difficult due to variation in

testing sample preparation and model gases used [49,50]. In par-

ticular, photocatalytic reactions have been reported to be strongly

dependent on film thicknesses and amount of active material [48].

However, Maneerat et al. reported that ST-01-coated polyesternonwovens showed 49% removal of toluene under JIS protocol

[49]. It is noted, however, that the fibrous and porous structure

of our sample should lead to large surface area for adsorption and

decomposition of the model toxin. Unlike spherical-shaped TiO2

nanomaterials, the nanofibers did not show any agglomeration

among the primary particles (Fig. 1b). This entailed low produc-

tion cost in practical uses and future industrial production. While

these results implied that the TiO2  nanofibers could be effective in

air pollution abatement, their ability to reduce microbial infection

might push their potential application further.

To further enhance their anti-microbial activity, the TiO2

nanofibers were decorated with silver nanoparticles via pho-

toreduction. In so doing, aqueous-base photoreduction of silver

ion in the presence of the nanofiber suspension resulted in

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Fig. 2. Decomposition of NOx and toluene under JIS protocol. (a) TiO2  nanofibrous membrane showed 21% efficiency for the decomposition of nitrogen oxide (NOx). (b) A

similar membrane showed 30% removal of toluene.

nanosilver-decorated TiO2 nanofibers. Fig.3a reveals SEMimages of 

the resulting hybrid nanofibers. It could be seen that the nanosized

silver particles were randomly distributed along the nanofibers’

surfaces. As shown in Fig. 3b, TEM image showed more clearlythat these nanosized silver particles attached onto the surface of 

the nanofibers. The results implied that photoreduction of silver

ions and formation of silver nanoparticles occurred on the sur-

face of the fibers. Since independent silver nanoparticles were not

observed, it could be said that silver nanoparticles appeared only

on the nanofibers’ surfaces. Furthermore, a high magnification TEM

image in Fig. 3c revealed the spherical shape of these silver parti-

cles. By elemental mapping of silver under SEM (Fig. 3d), it could

be seen that the silver particles were homogeneously distributed

all over the coated layer. This was consistent with Fig. 3a.

The presence ofsilveron the TiO2 couldbe further corroborated.

The crystal structures presented in the TiO2   and nanosilver-decorated TiO2   nanofibers were determined by powder X-ray

diffraction or XRD method as shown in Fig. 4. The XRD pattern of 

TiO2   nanofibers (Graph 4a) exhibited characteristic reflections at

2  of 25.0◦, 38.5◦, 48.2◦, 55.3◦, 63.6◦ and 75.0◦ corresponding to

(10 1), (00 4), (20 0), (10 5), (21 1)and(2 04) planesof the anatase

phase, respectively. After the photoreduction of silver ions, these

characteristic reflections remained with some additional reflec-

tions present (Graph 4b). These reflections at 38.2◦, 44.4◦ and 64.7◦

Fig. 3. Physical characteristics of nanosilver-decorated TiO2 nanofibers. (a)SEM micrograph of nanosilver-decorated TiO2 nanofibers. (b) TEMimage of nanosilver-decorated

TiO2 nanofibers. (c) High magnificationTEM image of thefibers. (d) Elementalmappingof silver by SEM. The white spotscorresponded to clusters of silverelement.

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Fig. 4. Structural characterizations by XRD. (a) XRDpattern of TiO2  nanofibers. (b)

XRD of TiO2  nanofibers after the photoreduction of silver ions.

represented (11 1), (20 0) and (22 0) planes of the face-centered

phase of silvermetal [35,36,43]. Finally, theaverage size of nanosil-

ver decorating on the fibers was calculated from FWHM to be

32nm. From these results, it could be said that the silver nanopar-ticles had been successfully deposited on the TiO2 nanofibers.

In a subsequently investigation, the antimicrobial activity of 

titanium nanofibers was tested after nanosilver deposition using

agar diffusion test as shown in Fig. 5. The antimicrobial activity of 

the nanofibers can be summarized in Table 1. From the table, TiO2

nanofibers showed no inhibitory zone, implying that the materi-

als comprised no antimicrobial property without UV. In contrast,

their nanosilver-decorated counterparts showed clear inhibitory

zones which expanded with the increase of nanosilver extent. The

influence of nanosilver on both Gram positive and Gram nega-

tive bacteria suggested that inclusion of nanosilver enhanced the

antimicrobial activity of the nanofibers.

 Table 1

Formation of inhibitory zones.

Materials Zone of Inhibition (mm)

Staphylococcus

aureus ATCC6538

Escherichia coli

ATCC 25922

TiO2  Nanofibers 0.0 0.0

P25 0.0 0.0

1% Ag–TiO2  Nanofibers 0.8 0.5

2% Ag–TiO2  Nanofibers 0.8 0.5

5% Ag–TiO2   Nanofibers 1.5 1.0

10% Ag–TiO2   Nanofibers 1.5 1.0

In agreement with the above result, nanosized silver particles

have been shown to be potent antibacterial agents [51,52]. Their

antibacterial property correlated strongly with their sizes. Even

though the nanoparticles could directly interact and damage cell

membranes, the antibacterial activity of nanosilver was usually

explained in terms of the interaction between the cell membranes

and silver ions, which released from the surface. Since particles’

surface area increasedwith the decrease in diameter, smaller silver

particles tended to show more potent antibacterial activity.

Silvernanoparticles mightnot only affectthe antibacterial char-

acteristics, but also influence the photocatalytic performance of TiO2. To further understand the roles of nanosilver-decorated TiO2

nanofibers as photocatalysts, the photodegradation of methylene

blue (MB) was carried out as shown in Fig. 6. As illustrated, C 0and C were the initial concentration of MB and that after a given

period of UV lightirradiation, respectively. For all nanofibroussam-

ples and P25 as a reference, the concentration of MB decreased

with time. While deposition of nanosilver influenced the pho-

tocatalytic performances, 2% and 10% nanosilver-decorated TiO2

nanofibers resulted in the highest and lowest photocatalytic per-

formances, respectively. The reduction of activity in the latter

might come from high surface coverage of nanosilver on the TiO2

nanofibers. In contrast, the 2% nanosilver inclusion left the activity

Fig. 5. Agar diffusion tests. Top and bottom rows represented Gram positive and Gram negative bacteria, respectively. (a) and (b) represented TiO2  nanofibers. (c) and (d)

represented P25. (e) and (f) represented silver-decorated TiO2  nanofibers.

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Fig. 6. Photodegradation of methylene blue (MB). As illustrated, C 0 and C were the

initial concentrations of MB and that after a given period of UV light irradiation,

respectively.

significantly enhanced. Nanostructured silver had been known to

act as an electron trapping site which reduced the electron–holerecombination rates and, thus,improved the photocatalytic perfor-

mance of TiO2   [38,53]. It was assumed herein that nanosilver also

behaved as such and the recombination rate in the 2% nanosilver

sample was reduced.

To strengthen this assumption, the electron–hole recom-

bination rate of each sample was indirectly monitored from

their photoluminescence (PL). The correlation between the

electron–holerecombinationrate and photoluminescence in a pho-

tocatalytic sample couldbe foundelsewhere[54]. Inshort,themore

electron–hole recombination rate, the more photoluminescence.

As illustrated in Fig. 7, PL intensity decreased with the increase

of nanosilver deposition. The results were consistent with the

assumption that nanosilver acted as electron trapping sites where

the interface between nanosilver and TiO2 formed heterojunctions

[53]. Increasing the amount of nanosilver on TiO2  nanofibers’ sur-

face subsequently increased heterojunctions between these two

entities [55]. Hence, the electron–hole recombination on the tita-

nium dioxide nanofibers’ surfaces was reduced, giving rise to a

weaker PL signal in the more heavily nanosilver-decorated sam-

ples. From the MB degradation and PL measurement, it could be

summarized that, in low density, nanosilver helped improve the

performance of the nanofibers. However, in high surface cover-

age, silver might downgrade the efficiency of the photocatalyst.

From these results, it could be said that silver nanoparticles not

Fig. 7. Photoluminescence (PL) intensity as a function of nanosilver extent.

Fig. 8. Static contact angles,  s, as a function of UV irradiation time. (Inset) Water

dropletson P25,TiO2 nanofibrous and nanosilver-decorated TiO2 nanofibrouslayers

were shown on thetop, middle andbottom series, respectively.

only imparted the antibacterial characteristics, but also influenced

the photocatalytic performance of TiO2

.

While the antibacterial and photocatalytic activities were cru-

cial for nanofiltration applications, the interfacial properties might

play a significant role during maintenance processes. From the

above rationale, interfacial phenomena on the nanofiber coated

layers were unveiled by contact angle measurements to exam-

ine their wetting characteristics. Static contact angles,  s, were

recorded after a given interval of UV irradiation. Shown in Fig. 8,

the static contact angles of both TiO2   and nanosilver-decorated

TiO2  nanofibrous layers decreased as a function of UV irradiation

time. Those of P25 were given as a reference. At 0 h, or without any

UV irradiation, the TiO2 and nanosilver-decoratedTiO2 nanofibrous

layers showed contact angles of 38.7◦ and 27.8◦, respectively. The

latter result implied that nanosilver imparted hydrophilicity onto

the TiO2  nanofibers. After 1 h of UV irradiation, the contact angles

of both layers decreased substantially. Furthermore, after 4h of UV irradiation, both layers showed superhydrophilicity with static

contact angles around and less than 10.0◦. In such condition, it was

observed that water droplets spread rapidly on the surface of the

membranes. It was strongly believed that this result would be use-

ful in maintenance of the membrane when used in nanofiltration

applications.

5. Conclusions

The potential use of nanosilver-decorated TiO2  nanofibers for

toxin decomposition with antimicrobial activity and self-cleaning

properties was investigated. TiO2   nanofibers were prepared viaan electrospinning process. Following Japan Industrial Stan-

dard (JIS) protocol, decompositions of nitrogen oxide (NOx) and

volatile organic compound (VOC) showed 21% and 30% efficiency,

respectively. The samples showed enhanced antimicrobial activ-

ity after nanosilver inclusion. Photodegradation of methylene blue

revealed that addition of 2% nanosilver significantly enhanced

the photocatalytic performances of TiO2   nanofibers. From the

photoluminescence measurements, nanosilver might play a role

in reducing electron hole recombination rate. Additionally, the

nanofibrous membranes prepared from these nanofibers showed

superhydrophilicity under UV. Finally, it is possible to apply these

hybrid nanofibers in environmental and hygienic nanofiltration,

as the self-cleaning characteristic was expected to be valuable in

maintenance processes.

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