Removal of Tetracycline from Aqueous Solution by Biochar Derived from Bagasse via Co-pyrolization with Polythene

Abstract

With the increasing health and environmental problems, pharmaceutical antibiotics have become dangerous contaminants in water discharging from hospitals and pharmaceutical industries. In this study, tetracycline was removed from water using pristine and modified biochars derived from sugarcane bagasse. Four different biochars were produced at two different pyrolytic temperatures, i-e, 500 ℃ and 700 ℃. Two of them were produced by simple pyrolysis (B500 and B700), and other two via co-pyrolization of bagasse with polythene (BP500 and BP700). Sorption experiments were conducted in batch mode to determine the adsorption capacity of four biochars towards tetracycline. The results revealed that biochars produced via co-pyrolization have a higher ability to remove tetracycline than those made through simple pyrolization. The maximum removal of tetracycline (96.55%) was observed for BP700. Four isotherm models (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich) were applied to the adsorption data of tetracycline, and results showed that all models were best fitted to the modified biochars (BP500 and BP700) based on the R2 values (0.992 to 0.998). Among kinetic models, the pseudo-second-order model well explained the sorption of tetracycline onto different biochars (R2 ≈ 1), indicating chemisorption as the dominant mechanism of interaction of tetracycline with biochars. Overall, co-pyrolized biochars showed greater removal efficiency and adsorption capacity towards tetracycline than simple pyrolized biochars. Hence, co-pyrolysis of biomass with polythene could produce biochars with greater adsorption potential of removing antibiotics from water.