Nanosheets-MnxOy anchored biochar for efficient removal of methyl blue and tetracycline from water

Abstract

Currently, the increasingly severe pollution of organic wastewater from dyes and antibiotics has become one of the major causes for the deterioration of the water environment. In this work, nanosheets-MnxOy anchored biochar (MnxOy@BEP) obtained from the marine polluting algae Enteromorpha was synthesized by a hydrothermal method, which exhibited extraordinary adsorption performance for tetracycline (TC) and methyl blue (MB). Nanosheets-MnxOy was grown in situ on the surface of biochar by pyrolysis of KMnO4, and the MnxOy@BEP composite had a micronano hierarchical structure, a larger specific surface area (208.735 m2 g−1) and more abundant active adsorption sites. Because of these characteristics, the MnxOy@BEP composite was endowed with excellent performance of organic pollutants in aqueous solution, which exhibited a high equilibrium adsorption capacity for TC (102.25 mg g−1) and MB (798.8 mg g−1), a rapid adsorption rate for MB (within 6 min) and selective adsorption properties at controllable pH. The experimental data of MB and TC was better fitted to the Langmuir isotherm model and pseudo-second-order kinetic model. Furthermore, the adsorption mechanism mainly involves electrostatic interactions, π-π interactions, hydrogen bonding, steric hindrance, etc. In addition, three cycles of adsorbent regeneration via 1.0 M NaOH solution displayed additional attractiveness. Therefore, the MnxOy @BEP composite material not only contributes to the management of Enteromorpha pollutants but can also be regarded as an extraordinary candidate for the removal of dye and antibiotic water.