Efficient adsorption of dyes from aqueous solution using a novel functionalized magnetic biochar: Synthesis, kinetics, isotherms, adsorption mechanism, and reusability

In this study, a novel adsorbent, dodecylbenzene sulfonic acid (DBSA) functionalized magnetic biochar (DBSA-Fe3O4@BC), was synthesized and used to efficiently remove dyes from aqueous solution. The results indicated that DBSA-Fe3O4@BC exhibited an excellent adsorption capacity for Rhodamine B (RhB), and the maximum adsorption capacity for RhB at 298 K was 367.67 mg/g, which was approximately 2.3–1.2 folds than that of BC, dodecylsulfonic acid functionalized biochar ([email protected]), [email protected], Fe3O4@BC, and DSA-Fe3O4@BC. The possible adsorption mechanisms for RhB adsorption by DBSA-Fe3O4@BC included pore filling, electrostatic attraction, H bond, and surface complexation. Importantly, structural control presented that the simultaneous introduction of alkyl and phenyl groups significantly enhanced RhB adsorption by DBSA-Fe3O4@BC through hydrophobic and π-π interaction. Combined ethanol (EtOH) desorption and H2O2 oxidation regeneration, DBSA-Fe3O4@BC remained high-performance for RhB adsorption after six cycles (97.44%), indicating its outstanding reusability. In summary, DBSA-Fe3O4@BC exhibited a prospective application for dyeing wastewater treatment.