Removal of benzo (a) anthracene from water using a novel UAE sludge-based activated adsorbent

A new adsorbent material from sewage sludge of relatively high surface area (2,230 m(2)/g) was prepared by carbonization and chemical activation using steam at controlled semi-static conditions. The pore size distributions of the sludge-based activated adsorbent (SW-A2) and commercial activated carbon were compared and found to be remarkably different with noticeable presence of larger micro-pores and small meso-poresfor SW-A2. The newly developed activated adsorbent was then evaluated for the adsorption of a polycyclic aromatic hydrocarbon (PAH); benzo (a) anthracene. The adsorption isotherms of benzo (a) anthracene on the adsorbent materials were fitted to both Langmuir and Freundlich isotherms. The Langmuir isotherm was found to be the best fit for the adsorption of the benzo (a) anthraceneon ACwith K and q(max) of 0.43L/mg and 70.5 mg/g, respectively. On the other hand, the adsorption isotherm for SW-A2 was found to follow the Freundlich isotherm with K-f and n of 100.8 mg/g (L/mol)(-0.763) and 1.31, respectively. The adsorption kinetics for both adsorbents were found to follow pseudo second order kinetics with rate constant of 1.55 x 10(-4) g mg(-1) min(-1) for SW-A(2) and 1.44 x 10(-4) g mg(-1) min(-1) for AC. The results of this study indicate the high potential of the newly developed sludge-based adsorbent as an efficient and successful material for the removal of carcinogenic PAHs from water body.