Indian Journal of Chemical Technology Vol. 6, May 1999, pp. 146- 151

Activated carbon from krishnachura fruit (Delonix regia) and c·astor seed (Ricinus communis L.)

Mohammad Masbahuddin Howlader·, Quazi SohelHossain a,t, A M Sarwaruddin Chowdhury ' ·, A I Mustafa' & M A Mottalibb

3 Department of Applied Chemistry and Chemical Technology, University of Dhaka, Dhaka - 1000, Bangladesh,

b Department of Chemistry, Rajshahi University, Rajshahi , Bangladesh

Received 31 March 1998; accepted /5 April 1999

Activated carbons were prepared from the husk of krishnachura (De/onu regia) fruit and the hull of castor (Ricinus communis L. ) seed using zinc chloride and steam-N2 as activating agent. The activating agent steam-N2 was used only for kri shnachura whi le ZnCI2 was used both for activating krishnachura and castor samples. It was found that the adsorptive ca­pacity of carbons produced by using ZnCI2 and steam-N2 as act ivating agent is comparable with that of commercially avail­abl e samples. The adsorptive capacity was measured by permanganate method and the carbons produced were employed for the decolorization of molasses solution.

The production of good quality activated carbon from indigenous raw materials were studied extensively in different parts of the world and is still in progress l

-4.

In many earl ier applications of activated carbon, pri­mary consideration was giv.en to decolourizing prop­erties . Many industrial products contain adsorbable impurifi~ in such minute amounts that they are not detected by an ordinary analysis, but even so, the presence of stich impurities can cause difficulties in processing the products, or in its application and use l

-4

. In fact, various methods and types of activated carbon produced have been reporte by many scien­tists. Various workers produced activated carbon from di ffe rent indigenous raw materials such as jute stick5

.7

, jute seed husks, coconut she1l9, sal seed

husks lO, sunflower seed hull" , bagasse 12, nageswer

and mahua seed husks '3 etc. The adsorption capacity of activated carbon may be incr.eased to a large extent by treating the carbonaceous materials with certain activating agent such as steam, carbon dioxide, zinc chloride, calcium chloride, phosphoric aCl etc. unde, di fferent conditions.

The p!"esen en cavour has been contributed to the utihza lOn of the re latively common, cheap and Which are not use otherwise but abundantly available in-

tpresen t address : Department of Pharmac. , University of Science and Technology Ch 'ttagong (USTC), Banglacfesh. * Author for correspondence

digenous material in Bangladesh for the production of activated carbon. The materials selected are the frui ts of krishnachura (Delonix regia) and the hull of castor (Ricinus communis L.) as shown in Fig.!. Although both the plants are not cultivated or planted system­atically, they are quite available throughout Bangla­desh mainly in the rural areas. The former is widely used as fuel and the latter is being wasted after ex­traction of oil. Therefore, it was aimed to utilize this huge amount of krishnachura frui t and castor husk for the production of activat~d carbon and to evaluate the decolourizing capacity of the carbon produced. The zinc chloride activation process was carried out for castor seed husk and both zinc chloride and steam-N2

activation processes were carried out for krishnachura frui t.

Experimental Procedure Materials 'and Methods

Preparation and characterization of activated car­bons from krishnachura f ruits and castor seed

husks-The dried fiu its of krishnachura were decorti­cated and the castor seeds were dehulled manually. The hulls were ground separately to fine powder and stored separately as stock for carbonization. The car­bonization was carried out at different temperatures and periods of time using activating agent ZnCl2 for both samples. The activated carbon was also prepared by using steam-N2 as activating agent from krish-

HOWLADER et a/.: ACfIV A TED CARBON FROM KRlSHNACHURA FRUIT AND CASTOR SEED 147

Table I-The effect of variation of temperature on % yield

Temperature Krishnachura Castor °C % yield KMnO. adsorbed (mglg of carbon) % yield KMn04 adsorbed (mglg of carbon)

200 51.04 469.3217 52.74 743 .26 17

250 49.26 501.4560 48.22 954.1958

300 47 .21 529.8983 45 .14 1064.0434

350 46.01 581.7874 44.28 1113.3952

400 43.47 648.5709 42.98 1035.0918

450 41.49 731.8053 41.27 823:0610

500 36.95 690.3216 39.94 820.8208

550 33 .62 665.2910 39.71 716.3974

600 33 .09 623.0187 37.27 678.1895

Time of activation =2 h, ZnCI2 /powdered sample ratio = I: I

Table 2-Tpe effect of variation of the ratio of ZnCI2 to seed husk sample on .% yield

Ratio of ZnCI2to Krishnachura Castor powdered sample % yield KMn04 adsorbed (mglg of carbon) % yield KMn04 adsorbed (mglg of carbon)

0:1 51.64 170.6924 53.62 212.3 104

1:3 46 .69 261.1288 49.7 1 364.8 106

1:2 44.91 437.7216 46.23 647.7123

1:1 41.41 731.8053 44 .28 1113 .. 3952

2: I 40.09 1354.001.0 41. 8 1 1502.260 1

3: I 37.89 2048.8465 41 .27 !553.6079

4:1 37.86 2095.0643 41.06 1631.0216

5: I 37.2 1 Z 176.5517 40.63 1694.7126

6: 1 37.06 2115 .7603 40.61 1734.6728

Time of activation =2 h, temperature of activation =450°C for krishnachura and 350°C for castor sample

Table 3--The effect of variation of time of activation on % yield

Time of acti va- Krishnachura Castor tion % yield KMn04 adsorbed (mglg of carbon) % yield KMn04 adsorbed ( mg/g of carbon) mm

30 38. 89 1964.5208 43 .83 1426.2670

<+5 38.47 2016.2396 43 .77 1458.7298

60 3808 2106.2083 43 .08 1489.5601

75 38.26 2191 .4336 42.67 1502.6094

90 38 .2 1 2185.3600 42.19 1579.7206

105 38.04 2 148.3908 42.02 1556.2601

120 37.89 2048.8465 41.81 1502.3202

150 36.93 2066.704 1 41.27 1495.6027 180 36.01 2038.9526 40.46 1478.4568

Temperature of actlvation=450°C for Krishnachura and 350°C for castor sample, ZnCI2 powdered sample=3: 1 for Krishnachura fruit and 2: I for castor husk.

148 rNDIAN J. CHEM. TECHNOL., MAY 1999

nachura fruit husk. The activated carbons thus pro­duced were evaluated by measuring the adsorption of KMn04•

Results and Discussion Based on permanganate number and yield, the op­

timum conditions such as temperature, the ratio of ZnClz to husk and time of activation were determined for the production of activated carbons. The results are shown in Tables 1, 2 and 3.

Data contained in Tables 1, 2 and 3, illustrate that temperature, Zr.CI /seed husk ratio and time have significant effect on adsorptive power of the activated carbon prepared. However, the % yield was observed to decrease with increase in the selected variables, the adsorptive power increase steadily, reaches maximum at certain points and then falls slowly but the percent­age yield of product gradually decrease with increase of all these variables.

The optimum production condition for activated carbon with maximum yields are ZriCl/husk ratio 3 : I, activation temperature 450°C and time 75 min for krishnachuta fruit husk and 2: I, 350°C and 90 min for castor seed husk, respectively. At these conditions the pemlanganate number and yield were 2191 mg/g. C and 38.26% for krishnachura fruit husk and 1579 mg/g. C and 42.19% for castor seed husk, respec­tively. In steam-N 2 activation process, the optimum production conditions for activated carbon with maximum yie lds on the basis of permanganate num­ber were determined . The results are shown in Tables 4 and 5.

From Tables 4 and 5, it is seen that at temperature 250°C, the adsorptive power increases with increase of ti me of activation but the percentage yield of prod­uct gradua lly decreases with increase of activation time .

In steam-Nz act ivation process, the optimum pro-

Table 4--The effect of variation of temperature

ample Flow rate of steam Flow rate of nitrogen Temperature % yield

product g.water/h bubbles/min °C

K rishn achu ra 310-330 80-90 200 54.23

carbon (act i- 250 52.97 vatcd by 300 50.18 Stcam- N, ) 350 50.01

400 46.72

450 43.29

500 41.60

550 40.94

600 40.05

Time of activation =2 h

Table S--The effect of variation of time of activation

Sample product

Krishnachura carbon (activated by Steam-N1 )

Flow rate of Steam Flow rate of nitrogen Time of activation g.waterlh bubbles/min min

310-330 80-90 60

90

120

150

180

210

240

270

300

Temperature of activation =250°C

% yield

57.92

54.31

52.97 50.84

49.68

47.23 46.29

44.56

43.02

KMn04 adsorbed mg/g of carbon

953.0907

1103.6823

1079.520 1

997.7025

90 1.2160

819.6043

954.2419

907.1102

872.0297

KMn04 adsorbed mg/g of carbon

547.1817

763.2915 1095.7869 1179.4164

1223.7912

1245.2576 1248.6953

1277.2146

1283.3475

).

HOWLADER et af.: ACTIVATED CARBON FROM KRISHNACHURA FRUIT AND CASTOR SEED 149

Fig. I-(a) Krishnachura fruit and (b) castor seed

duction conditions for activated carbon with maxi­mum yields from krishnachura fruit husk on the basis of pennanganate number are temperature of activa­tion 250°C, time of activation 180 min and pennan­ganate number and yield were 1223 mg/g C and 49.68% respectively.

The physical properties of the activated carbons thus produced are comparable with those of commer­cially available decolourizing carbon. The apparent density, ash content and pH of carbons, produced from krishnachura fruit husk (activated by ZnCI2),

castor seed husk (activated by ZnCI2) , and krish­nachura fruit husk (activated by steam-N2), were found to be 0.372 glcc, 1.33% and 5.65; 0.708 glcc, 2.45%, and 5.6; and 0.450 g/cc, 1.93%, and 5.63, re­spectively.

Preparation and decolourization of molasses solution

The molasses solution was prepared by dissolving a known amount of molasses 2.5 g (ash 11.71% , water 29.6%) in 500 mL of distilled water. A meas­ured amount of molasses solution (20 mL) was

70

60

50

! o

o - KRISlfiACHURA CARBON (ZoCI2)

11 - CASTOR CARBON o - KRIS'-<:HURA CARBON (STEAM - N2 )

°

° i 40

o

~ 30

I o

20

o--__ ~U----,D~---cOr----~ 10L-__ ~ ____ ~ ____ -L ____ -L ____ ~ ____ ~

40 50 60 10 eo 90 100

Temperature , ·C

Fig. 2-The effect of temperature on adsorption of colour.

70.-----------~----------------------,

:10

o - KIIISHNAC_' C"'_ (Z""2)

'" - C.STO. C"'_ o - UISt4I01CHU.' C ••• ON(STI ... -NZ)

! 40 . C , .; 30 ...

20 ~ x ZI .0.

~ 0 0 0

10

20 30 40 50 60 70 o~ __ ~ ____ ~ __ ~ ____ ~ __ ~ ____ ~ ____ ~

o 10

Tim. f Min _

Fig. 3--The effect of time of contact on adsorption of colour.

treated with a known amount ot activated carbon (0.1 g) for a period of time at different temperatures. The hot solution was filtered and after cooling the filtrate . was analyzed using a spectrophotometer.

The effect of temperature (50-100°C) on the re­moval of colour from molasses solution is repre­sented graphically in Fig. 2. It is evident that with increase of temperature from 50-80°C, the removal of colour by krishnachura carbon (activated by ZnCI2)

150 INDIAN J. CHEM. TECHNOL., MAY 1999

Table &-The effect of variation of different dosages of carbon on adsorption of colour

Sample Temperature Time of Amount of ' Colour unit Colour unit Colour unit adsorbed products °C contact carbon in g retained adsorbed per g of carbon

K rishnachura carbon (activated by ZnCI2 )

Castor carbon (activated by ZnCI2 )

Kri shnachura carbon (activated by steam-N 1 )

Ori ginal co lou r = 100 units

80

60

60

min M

30 0.025

0.050

0.075

0.100

0.150

0.200

0.300

20 0.025

0.050

0.075

0.100

0.150

0.200

0.300

20 0.025

0.050

0.075

0.100

0.150

0.200

0.300

was increased steadily but br;:yond this range, the ad­sorption of colour did not increase appreciably. For castor carbon (activated by ZnClz), the adsorption of colour increased at slower rate through temperature 50-70°C but beyond that range, the adsorption did not increase markedly. For krishnachura carbon (acti­vated by steam-N2), the adsorption was in tempera­ture range 50-60°C and beyond that the adsorption of color remained almost constant. The colour removed by krishnachura carbon (activated by ZnClz), castor carbon (activated by ZnCI2), and krishnachura carbon (activated by steam-N2) were 35 .51 %, 21 .38% and 12.93% respectively, for contact time 10 min and temperature 50°C, while at 80°C for the same contact time the colour removed were 61.13%, 25.87% and 13.30% by krishnachura carbon (activated by ZnClz), castor carbon (activated by ZnClz), and krishnachura carbon (activated by steam-N2), respectively. To avoid loss of water by evaporation at the temperature above 80°C, the experiment was carried out in the

C X XIM

82.06 17.94 717.60

63.76 36.24 724.80

49.82 50.18 669 .07 34.31 65 .69 656.90

27.18 72.82 485.47

14.81 85 .19 425 .95 05.25 94.75 315.83

89.02 10.98 439.20 85.36 14.64 292.80

81.36 18.64 248.53 78.00 22.00 220.00

76.30 23.70 158.00

74.36 25 .64 128.20

71.30 28.70 095 .67

93.86 06. 14 245.60

91.28 08 .72. 174.40

88.67 11.33 151.07

85.50 14.50 145 .00

83.28 16.72 111.47

81.67 18.33 091.65

78.86 21.14 070.46

conical flask fitted with an upright condenser. There­fore, all the subsequent experiments were carried out at 80°C, 60°C and 60°C for krishnachura carbon (ac­tivated by ZnCI2), castor carbon (activated by ZnCI2), and krishnachura carbon (activated by steam-N2), re­spectively.

Fig. 3 shows the effect of time of contact on ad­sorption of colour from molasses solution at 80°C, 60°C and 60°C for krishnachura carbon (activated by ZnCI) , castor carbon (activated by ZnClz), and krish­nachura carbon (activated by steam-N2), respectively, with 0.5% carbon. It was observed that the rate of adsorption of colour by carbon produced from krish­nachura (activated by ZnCI2) was increased sharply within 5 min while the rate of adsorption of colour was not appreciable for castor carbon (activated by ZnCI2), and krishnachura carbon (activated by steam­N2)' The rate of adsorption of colour increased gradu­ally with increase in contact time but the colour ad­sorption did not gear-up significantly after 30, 20 and

HOW LADER et al.: ACTIVATED CARBON FROM KRISHNACHURA FRUIT AND CASTOR SEED lSI

20 min fodaishnachura carbon (activated by ZnCI2),

castor carbon (activated by ZnCI2), and krishnachura carbon (activated by steam-N2), respectively. There­fore, in the subsequent experiments, temperatures of 80, 60 and 60°C, and contact time of 30, 20 and 20 min fNere maintained for krishnachura carbon (acti­vated by ZnCI2) , castor carbon (activated by ZnCI2) ,

and krishnachura carbon (activated by steam-N2) re­spectively.

Results of the effect of different dosages of carbon on adsorption of colour are shown in Table 6. From Table 6, it is clear that colour removal increases' steadily with the increase of the dosages of carbon.

During the evaluation of adsorptive capacity of the carbon produced, it was found that O.S % carbon (i .e., 0.1 g carbon for decolouring 20 mL of molasses so­lution), produced from krishnachura fruit husk (acti­vated by ZnCI2) , castor seed husk (activated by ZnCI2), and krishnachura fruit husk (activated by steam-N2), brought down the colour units of molasses solution from 100 to 34.31 in 30 min at 80°C, to 78.00 in 20 min at 60°C and to 8S.S0 in 20 min at 60°C, respectively.

Conclusion Krishnachura fruit husks can be used as raw mate­

rial for the production of high quality activated car­bon using ZnCl2 as activating agent.

Acknowledgement This paper is dedicated to the memory of the late

Professor Dr. Mohammad Altaf Hossain, Department of Applied Chemistry and Chemical Technology, Dhaka University, whose valuable contribution through guidance, discussion and criticism inspired us. Thanks are due also to Dr. M. Hassiruzzaman for his cooperation in UV spectrophotometer operation.

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