Sorptive removal of β-blocker propranolol from aqueous solution by modified attapulgite: Effect factors and sorption mechanisms

The present study investigated the feasibility of using modified attapulgites for the sorptive removal of beta-blocker propranolol. The attapulgites were modified by different reagents including hydrochloric acid, silane coupling agent and chotosan. And the modified attapulgites were characterized by N-2 sorption-desorption, Fourier transform infrared spectroscopy, zeta potential measurements, and X-ray diffraction technique. The as-made attapulgites were applied to removing propranolol from aqueous solution, and the effects of pH, ionic strength. sorbent dosage, and humic acid on sorption were investigated by batch experiments. The sorption capacity of the as-made attapulgites was compared with that of natural attapulgite, powdered activated carbon and other reported sorbent. The results suggested that the acid-activated attapulgite had a higher sorption capacity for propranolol than the other sorbents involved. The sorption kinetics and equilibrium isotherms of propranolol onto acid-activated attapulgite were also studied. The sorption process followed the pseudo-second order equation and the sorption data were fitted well with the Langmuir isotherm equations. Both physisorption and chemisorption played important roles for propranolol sorption onto acid-activated ATP. Owing to its high sorption capacity and low cost, acid-activated attapulgite has potential value in the removal of propranolol from sewage and natural waters in engineering application. (C) 2011 Elsevier B.V. All rights reserved.