Heterogeneous activation of peroxymonosulfate by Co3O4 loaded biochar for efficient degradation of 2,4-dichlorophenoxyacetic acid

Abstract

Carbon-based catalysts have the advantage of biological cleaning and cost-effectiveness in water treatment. This work used a two-step calcination method to prepare a novel nanometer composite material (CBC-1), where flake-like Cobalt oxide (Co 3 O 4 ) loaded on rice husk biochar. CBC-1 was used to activate PMS and degrade 2,4-dichlorophenoxyacetic acid (2,4-D) in the water phase. SEM, XRD, FT-IR, BET, XPS, EPR and other characterization methods showed that both sulfate radical and hydroxyl radical were involved in 2,4-D degradation. Both the high hydroxyl (-OH) content and Co (II) of the catalyst are beneficial to the activation of PMS. The pseudo-first order reaction rate constant of CBC-1 was 5.3 and 16 times that of pure Co 3 O 4 and biochar. This research provides new ideas for the application of carbon-based materials in the water treatment process and achieves the goals of treating waste water polluted by pesticides effectively and resource utilization of agricultural waste. • Provided a new view for the waste utilization of rice husk. • Enhanced the catalytic activity of Co 3 O 4 with rice husk biochar added. • CBC-1/PMS system exhibited satisfactory degradation efficiency of 2,4-D within 10 min. • The higher hydroxyl content of CBC-1 is helpful for enhancing the catalytic ability.