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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