Adsorption and one-step degradation-regeneration of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid using biochar-based BiFeO3 nanocomposites

Abstract

A microwave (MW)-assisted-H₂O₂ technique used to revise 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid (H-acid)-saturated biochars (BCs) was investigated in detail. This method could simultaneously degrade the H-acid adsorbed in the BCs-based BiFeO₃ (BFO) nanocomposites (BFO/BCs), in which BFO was used as dopant intercalated into BC, and activate the used BCs. Because H-acid could be decomposed by OH, which was generated in a coexistent system, including MW irradiation, H₂O₂, and BCs. It's worth noticing the adsorption capacity was (236.8mgg^-1) 1.1-fold higher than that of unused BFO/BC (211.7mgg^-1). It indicated that the surplus OH exhibited a cooperative effect with MW irradiation to restore H-acid-saturated BCs via the cleavage of CC bond, thereby forming carboxylic groups and the pyrolysis effect. Findings indicated that the one-step degradation-regeneration method could effectively promote the adsorption capacity of H-acid-saturated BCs in a few minutes and could thus be considered a potential technology in water treatment.

Keywords: Biochar-based BiFeO(3) nanocomposites; Degradation-regeneration; H(2)O(2); H-acid; Microwave.