Indian Journal of Chemical Technology Vol. 2, May 1995, pp. 137-141 Phenol removal from aqueous systems by sorption on jackwood sawdust V Sivanandan Achari & T S Anirudhan Depilftment of Chemistry, University of Kerala, Trivandrum 695 581, India Received 4 April 1994; accepted 24 July 1994 The adsorption technique using sawdust of jackwood timber has been applied for the removal of phenol from aqueous solutions. The extent of removal was dependant on concentration, pH and temperature of the solution. With an initial cQncentration of 25 mg/L at 30°C and pH 7, the remo- val was found to be 62.5% by using sawdust as adsorbent. The time to reach equilibrium was found to be 6 h. The higher uptake of 79.2% of the initial concentration of 25 mg/L occurs at pH 5.5 at 30°C. The applicability of Freundlich isotherm to the sawdust-phenol system was tested at 10, 20 and 30°C at pH 5.5, which can be used for the design of wastewater treatment plants. The spent ad- sorbent can be regenerated and reused by acid treatment. Phenol and its derivatives are toxic contaminants in aquatic environments and impart objectional taste and odour to water and is toxic to fish1.2. The permissible limit for phenol in potable water is 1 ,uhlL. The human consumption of phenol contaminated water can cause severe pain and ul- timate damage to capillaries. The studies showed that adsorption technique is an effective method for phenol removal3• Several lowcost substances such as cellulosic materials, peanut skins, onion skins, bambara nuts, rice husks and waste tea leaves are found to be the effective adsorbents for toxic metallic ions present in sewage and waste water4 - 8. It has been reported that sawdust is a good adsorbent for removing heavy metals from wastewater9• Detailed studies on the sorption of metal ions such as Cd2+ and Cu2+ onto sawdust have been uI}dertaken by sever~ groups of inves- tigators 10 - 11. However, the adsorption behaviour of phenol on sawdust has not so far been studied. The present study is intended to the use of this locally available conventional cheap material, as a phenol adsorbent. This adsorbent is a by' product of timber and plywood industries. It finds a little use either as a cheap fuel, or a packing material. The experimental material is collected from jack- wood timber which is widely used for furniture and housemaking in Kerala due to the durability of its hardwood portion. The availability of saw- dust is maximum in Kerala. In the study the hard- wood portion of jackwood is used as an adsor- bent for phenol removal from aqueous effluent si- mulated in the laboratory conditions. Experimental Procedure Sorbent -The sawdust of hardwood portion of jackwood was collected under hygienic ,conditions from a local t4nber industry. After drying, the particles of 8{)- 230 mesh size were separated by sieving through standard test sieves. Then it was boiled in distilled water continuously for 30 min. The suspension was then left to settle to allow the supernatant to be poured off. This process was repeated several times until the coloured water soluble components were removed. Finally the washed adsorbent was dried in an oven at 80"C, allowed to cool and sieved into 80-230 mesh size for subsequent use. Chemicals- All the reagentls and chemicals used were of A R Grade (BDH). The solutions were prepared in double distilled water. A stock solution of phenol was prepared by dissolving 1g phenol in distilled water in 1000 mL capacity vol- umetric flask. A solution of 0.1 M NaNO) was used to maintain constant ionic strength. The pH of the medium was adjusted by using 0.1 M HN03 and 0.1 M NaOH solutions. The phenol estimation was done spectrophotometrically by the 4-amino antipyrine method using a Bausch and Lomb Spectronic 21D12. The pH of the sub- strate was determined using a pH meter Elico model U-120. Batch adsorption kinetics-The batch experi- ments were conducted using 1g of sawdust in a 250 mL capacity stoppered bottle with 100 mL of phenol solution. The adsorbate concentrations were varied in the range of 25-1000 mg/L. The