Preparation and characterization of activated carbons from waste tea by H3PO4 activation in different atmospheres for oxytetracycline

In order to study the optimum atmosphere condition for preparing waste tea-based activated carbon by H3PO4 activation, activated carbons were prepared under nitrogen (NAC), air (AAC) and steam (SAC) atmospheres, respectively. The physicochemical properties of the three activated carbons were characterized by N-2 adsorption/desorption and Fourier transform infrared spectroscopy (FTIR). MC exhibited highest values of the Brunauer-Emmett-Teller (BET) surface area (880 m(2)/g) and total pore volume (0.680 cm(3)/g) than that of NAC (824 cm(2)/g and 0.666 cm(3)/g) and SAC (785 cm(2)/g and 0.629 cm(3)/g). Nevertheless, the adsorption results for oxytetracycline (OTC) showed that SAC had the strongest adsorption capacity than NAC and MC. The adsorption equilibrium data for OTC adsorption onto the three activated carbons agreed well with the Freundlich model, and the adsorption kinetics were well fitted in pseudo-second order model. Results revealed that activated carbon prepared under air atmosphere showed the largest BET surface area and activated carbon prepared under steam atmosphere showed the best adsorption capacity. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.