Adsorption of Congo Red on Various Activated Carbons. A Comparative Study

Studies on the removal of Congo Red (CR) by adsorption on variousactivated carbons [commercial activated carbon (CAC) and indigenously prepared activated carbons(IPACs) from raw materialslike bamboo dust, coconut shell, groundnut shell, rice husk, and straw] have beencarried out with an aim to obtain information on treating effluents from dye/textile industries. The effect of various experimental parameters has been investigated by following batchadsorption technique at 30 ± 1 °C. The percentage removal of dye increased with the decrease in initial concentration, initial pH of the dye solution and particle size of IPACs and increase in contact time and dose of adsorbent. Adsorption data were modelled with the Freundlich and Langmuir adsorption isotherms and first order kinetic equations such asNatarajan and Khalaf, Lagergren, Bhattacharya and Venkbachar equations and intra-particle diffusion model and the models werefound to be applicable. The kinetics of adsorption is observed tobe first order with intra-particle diffusion as one of the rate determining steps. Removal of dye using IPACs is found to be favourable and hence, IPACs could be considered as alternatives to CAC for the treatment of textile effluents, especially for theremoval of dye(s).