REMOVAL OF REACTIVE DYE REMAZOL BRILLIANT BLUE R FROM AQUEOUS SOLUTIONS BY USING ANAEROBICALLY DIGESTED SEWAGE SLUDGE BASED ADSORBENTS

Abstract

In this study, adsorbents were produced from sewage sludge via chemical and thermal activation processes. Experiments were carried out in a tubular furnace at a heating rate of 20 degrees C min(-1) and temperature of 550 degrees C with a nitrogen flow rate of 400 mL min(-1) for 1 h. Dye adsorption experiments were performed with Remazol Brilliant Blue R at several concentrations under batch equilibrium conditions by comparing sewage sludge based adsorbents with raw material and a commercial activated carbon. Maximum adsorption capacities of carbonized sewage sludge (CSWS) and activated sewage sludge (ASWS) were found as 7413 and 9.376 mg g(-1) for 100 mg L-1 dye solution, whereas commercial activated carbon had a capacity of 11.561 mg g(-1) Freundlich and Langmuir isotherms were used to explain the adsorption mechanism together with pseudo-first-order and pseudo-second-order kinetic models. The Langmuir isotherm, which had adsorption capacities of 34.60 (CSWS) and 7299 mg g(-1) (ASWS), provided a better fit to the equilibrium data than that of the Freundlich isotherm. The pseudo second-order model, which had adsorption capacities of 7451 (CSWS) and 9.319 mg g(-1) (ASWS), was very favorable to explain the adsorption kinetics of the dye with high regression coefficients.