Kinetics of adsorption of dyes by sludge activated carbon
污泥活性炭对染料的吸附动力学研究

In this paper,sludge activated carbon(SAC) was prepared from municipal wastewater treatment plant sludge using chemical activation (the activation reagent was ZnCl2),and the kinetics of adsorption of three dyes(Reactive Brilliant Red K-2BP,Acid Scarlet GR,Direct Violet N) by SAC was studied.The results indicate that the SAC can adsorb dyes effectively.The amount of each dye adsorbed at equilibrium(qe) increases with the increase of initial dye concentration or temperature.Using the same conditions,the order of qe of the three dyes is as follows: Acid Scarlet GR> Reactive Brilliant Red K-2BP >Direct Violet N.The adsorption of each dye by SAC follows the pseudo second-order kinetic model.For Reactive Brilliant Red K-2BP and Direct Violet N,the adsorption rate is not only controlled by intra-particle diffusion but also by extra-particle diffusion.However,for Acid Scarlet GR,intra-particle diffusion is not the rate-controlling step.The adsorption of each dye by SAC,which is an endothermic process,has a small energy of activation,and is mainly a physical adsorption process.