Kinetic and isotherm studies of adsorption and biosorption processes in the removal of phenolic compounds from aqueous solutions: comparative study

The phenolic compounds are known by their carcinogenicity and high toxicity as well as creating unpleasant tasteand odor in water resources. the present study develops a cost-effective technology for the treatment of watercontaminated with phenolic compounds, including phenol (ph), 2-chlorophenol (2-cp), and 4-chlorophenol (4-cp).so, two sorbents, rice bran ash (rba) and biomass of brown algae, cystoseiraindica, were used and results werecompared with the commercially granular activated carbon (gac). the phenolic compounds were determinedusing a high performance liquid chromatography (hplc) under batch equilibrium conditions. the effects of contacttime, ph, initial adsorbate concentration, and adsorbent dosages on the removal efficiency were studied.the adsorption data were simulated by isotherm and kinetic models. results indicated that rba and gac had thelowest efficiency for the removal of 2-cp, while the order of removal efficiency for c. indica biomass was as follows:2-cp > 4-cp > phenol. the efficiency of gac was higher than those of other adsorbents for all of the phenoliccompounds. furthermore, the adsorption capacity of rba was found to be higher than that of c. indica biomass.the optimal initial ph for the removal of phenol, 2-cp and 4-cp was determined to be 5, 7, and 7 for rba, gac,and algal biomass, respectively. kinetic studies suggested that the pseudo-second order best fitted the kinetic data.