INTRODUCTION:

The effluent of textile wastewater contains a large quantity of colure that is inert and may be toxic at the concentration discharge into receiving water. The discharge of highly colored effluents into natural water bodies is not only aesthetically displeasing, but it also impedes light penetration, thus upsetting biological processes within a stream. In addition, many dyes are toxic to some organisms causing direct destruction of aquatic communities. Some dyes can cause allergic dermatitis, skin irritation, cancer and mutation in human beings.

Although some existing technology may have certain advantages in the removal of dyes, their initial and operational costs are so high, that they constitute an inhibition to dying and finishing industries. On the other hand low cost technology does not allow a wishful colure removal or have certain disadvantages. Hence, this experiment has been directed to the material and procedure for dyes removal that will be effective as well as cheap.

Treatment of wastewater containing dyes by adsorption is an emerging field of research. The process of adsorption has an edge over other methods due to its sludge free clean operation and complete removal of dyes even from the dilute solutions. The commonly used adsorbent is activated carbon. However commercially available activated carbons are very expensive. Therefore there is a need to produce low cost and effective activated carbon that can be applied to water pollution control. The investigation reported here deal with the adsorption studies on activated carbon derived from H₃PO₄ impregnated baggasse for the removal of basic dyes from their aqueous solution.

EXPERIMENTATION:

Baggase

Also called MEGASS is the fiber remaining after the extraction of sugar bearing juice from sugar cane . It is a waste material obtained after all the juice has been extracted from sugarcane. The bagasse can be obtained from any sugar cane juice corner or sugar manufacturing industry.

Table 1: Composition of sugarcane baggase

S. No.	Properties	Approximate Value
1	Moisture	48% – 51%
2	Fiber	45% – 47%
3	Pol	1.5% – 2.5%
4	Brix	2.7% – 4.0%
5	Ash	2.5% – 3.0%
6	Calorific value at 50% moisture	1800 kilo cal/kg
7	Calorific value (Dry)	4600 kilo cal/kg

Table 2: Experimental data

S.No	% composition of Solution	Initial %T	Final %T
			For 1 Hr.		For 1.5 Hrs
			0.4 gm	0.6 gm	0.4 gm	0.6 gm
1	20%	41	97	98	98	99
2	40%	27	96	97	97	98
3	60%	15	95	96	96	97

Methylene Blue

Methylene blue is a bright greenish blue organic dye belonging to phenothiazine family. It is a widely used dye in chemical industry and has chemical formula C₁₆H₁₈ClN₃S.2H₂O. It has molecular weight of 409.93 and has dye content about 82% Adsorption (in water) 663-667mm.

Phosphoric Acid

It has Chemical formula H₃PO₄.It has molecular weight of 99. The most important oxygen acid of phosphorous also called ortho-phosphoric acid .Pure Phosphoric Acid is a crystalline solid melting point is 42.5^OC.

PROCEDURE

Baggase was collected from local sugar mill. It was washed with hot distilled water to remove dust and dried in sunlight. The baggase was treated with 50 % phosphoric acid and carbonized at 250⁰C for 5 and half hours. Before utilization and the carbon was washed with distilled water and dried in sunlight. Batch adsorption experiments were carried out by 50 ml dye solution (100 mg/l) with different adsorbent dosages, different time intervals and different compositions of dye solutions. The progress of adsorption was determined by Systronic UV–VIS spectrophotometer 118.

1. Three subdivided samples having concentrations of 20%, 40% and 60% were prepared in conical flask of 50ml.

2. These test samples were examined in UV – VIS Spectrophotometer to check the initial %T.

3. 0.4 gm of activated carbon from baggase was added in each conical flask .It was kept for 1 hr with periodic shaking.

4. After 1 hr the solution was filtered and final reading of %Transmittance was taken.

5. Same procedure was followed for 1.5 hrs.

6. The procedure was repeated for different weights of adsorbent, 0.6 gm.

RESULT AND DISCUSSION:

1. Effect of Amount of Adsorbent

Experiment was performed for two different amount of adsorbent and it was observed that higher amount of adsorbent produced more % T, when seen for constant composition and contact time. The same observation was noted for all the composition prepared from base solution.

For instance, the solution of 20% composition gave 97% transmittance for 0.4 gm of adsorbent and 98 % transmittance for 0.6 gm of adsorbent, when observed for 1 hr contact time.

2. Effect of Composition

The adsorption of Methylene blue decreases as the composition of methylene blue increases. Observations show that the process is highly dependent on composition of solution.

At low compositions (moles of dye to available surface area) the fractional adsorption becomes independent of initial composition. However at higher compositions the available sites of adsorption become fewer. Hence removal of dye is independent of initial composition.

It was observed from experiments that for 20% composition 97% transmittance and 96% transmittance for 40% composition for 0.4 gm of adsorbent and 1 hr contact time.

3. Effect of Contact Time

Three samples of different compositions were prepared. Observations were taken for constant amount of adsorbent but with different contact times. The %T for higher contact time was greater than the lesser contact time.

As can be seen from Table 1 for solution of 20% composition 98% transmittance was recorded for 1.5 hrs contact time where as 97% transmittance for 1 hr was recorded when amount of adsorbent was 0.4gm.

CONCLUSION:

The following conclusions can be made from the present work:

1. For a given composition, the adsorption of dyes in activated charcoal of baggase increases with amount of adsorbent when operated for equal contact time.

2. Rate of adsorption was decreased when composition was increased for the same amount of adsorbent and contact time.

3. With increase in contact time the adsorption of dyes in activated charcoal of baggase increases when the other two parameters i.e. amount of adsorbent and composition are same.

REFERENCES:

1. Anirudhan T.S. and Shreedhar M.K. (1998). Indian Journal of Chemical Technology. 5(1).

2. Khattri S. D. and Singh M.K. (1998). Indian Journal of Chemical Technology. 5(7).

3. Khodija M. (1998). Indian Journal of Chemical Technology. 5(1)

4. Verma V.K. and Mishra A.K. (2004). Asian Journal of Microbiol, Biotech Env. Sci. l6(2).

Received on 20.11.2011 Modified on 20.01.2012

Asian J. Research Chem. 5(5): May 2012; Page 620-622