Sorption of tetracycline on H2O2-modified biochar derived from rape stalk

To determine the sorption potential and mechanisms of tetracycline (TC) on pristine and H2O2-modified biochars, rape stalk biochars were produced and modified by H2O2. The specific surface area and pore volume of biochars increased with improving pyrolysis temperature, while the acidic groups decreased. Moreover, modified by H2O2, much more oxygen-containing functional groups were introduced. The results of sorption dynamics and isothermals tests showed that RB300 had the largest TC sorption capacity of 35.90 mg/g, which was ascribed to a plenty of non-carbonized organic matter and surface functional groups were retained. Modified by H2O2, the sorption of TC on biochars was enhanced which indicated the dominated sorption mechanisms were H-bonding and p-p electron donor acceptor interaction. The pH value would impact on sorption, and the maximum sorption capacity was obtained at pH = 9.0. Both cation concentration and type would affect the TC sorption.