KMnO4 modified biochar derived from swine manure for tetracycline removal

Abstract

Tetracycline (TC) is widely used in the livestock industry, but undigested TC is excreted with livestock waste and accumulates in the environment. In this study, swine manure-derived biochar (SBC) was modified with KMnO4 (MnOx-SBC), and used to remove TC. SEM-EDS, FTIR, XPS and elemental analysis all indicated that ultrafine MnOx particles were attached to the biochar surface. The surface properties and composition of the oxygen-containing functional groups were enhanced by KMnO4 modification. Batch sorption experiments showed that MnOx-SBC's TC-adsorption capacity was 105.9 mg·g−1, 46.4% higher than SBC's. The TC-adsorption onto MnOx-SBC agreed well with the pseudo-second-order model and Freundlich isotherm. A new platform is proposed for reusing swine manure while solving the livestock industry's antibiotic pollution risk by ‘treating waste with waste’. HIGHLIGHTS TC adsorption capacity of swine manure derived biochar enhanced after KMnO4 modification.; Initial solution pH, temperature and initial solution concentration affected TC removal.; Pseudo-second-order and Freundlich models can well fit the adsorption behavior.; Adsorption mechanism included pore-filling, surface complexation, π-π interactions and H-bonding.;

Keywords

• adsorption
• biochar
• modification
• swine manure
• tetracycline