Adsorption Capacity of Coconut Coir Activated Carbon in the Removal of Disperse and Direct Dyes from Aqueous Solution

The present research deals with the preparation of activated carbon from coconut coir and its adsorption behavior for textile dyes in comparison with that of a commercial activated carbon. The coconut coir activated carbon (CCAC) and commercial activated carbon (CAC) were characterised in terms of ash content, bulk density, pH, pHZPC, surface area, micropore area, micropore volume, average pore diameter, surface morphology and surface functional groups. Adsorption of two classes of textile dyes, Disperse Red 343 (DR 343) and Direct Blue 86 (DB 86), from aqueous solution by CCAC and CAC were examined. Batch adsorption test showed that extent of dye adsorption was dependent on dye concentration, contact time and pH. Equilibrium adsorption for DR 343 and DB 86 was attained in 1 and 2 h, respectively, and maximum adsorption occurred at pH 2 for both dyes. Equilibrium adsorption data of DR 343 and DB 86 were described by the Langmuir and Freundlich isotherm models, and the isotherm constants indicated higher adsorption capacity of CCAC for both dyes. CCAC is a suitable substitute for CAC in the removal of Disperse and Direct dyes from aqueous solution.