Insights into the Fenton-like degradation efficiency and mechanism of phenolic pollutants by Cu-doped sludge-based biochar catalyst

To effectively degrade phenolic pollutants, metal Cu was incorporated into sludge-based biochar (SBC), thereby creating a Fenton-like catalyst designated as Cu/SBC. This catalyst was combined with H 2 O 2 to establish a Fenton-like reaction system specifically designed for the catalytic degradation of phenol. In the experiment, the degradation efficiency of phenol was used as the evaluation index, and the optimal preparation conditions of Cu/SBC were screened. The results demonstrated that in Cu/SBC, SBC could be used as a carrier for electron transfer, while the addition of Cu was the key to enhance the performance of the catalyst. Under the catalysis of Cu/SBC, phenol in the concentration range of 100–350 mg/L were effectively degraded, achieving a 100 % degradation efficiency within 20 min. The physical and chemical characterization revealed that the surface of the material was uniformly covered with metal groups and a variety of functional groups, resulting in a porous structure with more abundant cavities, larger specific surface area and higher adsorbed oxygen content than the original sludge. The reaction mechanism analysis revealed that free radicals (such as •OH, •O 2 − , etc.) were produced in the Cu/SBC-H 2 O 2 Fenton reaction system, with •OH being the primary radical responsible for phenol degradation. In addition, a variety of intermediate products of phenol degradation were detected, and the possible mechanism of phenol degradation in this kind of Fenton system was proposed. In conclusion, the catalyst developed in this study exhibits excellent catalytic performance and provides valuable insights for research on the degradation of phenolic wastewater.