Electrons of d-orbital (Mn) and p-orbital (N) enhance the photocatalytic degradation of antibiotics by biochar while maintaining biocompatibility: A combined chemical and biological analysis

Photocatalytic oxidation technology holds promise for ideal advanced treatment of antibiotic wastewater. Single -atom catalysts (SACs) are a new hotspot in catalytic science, but the photochemical studies on the removal of antibiotics from water and biocompatibility after entering the environment are scarce. In this work, we prepared a single Mn atom immobilized on N-doped biochar (Mn@N-Biochar) by impregnation calcination method for enhancing photocatalytic degradation of sulfanilamide (SNM) in different types of various water systems. Compared with the original biochar, Mn@N-Biochar showed enhanced SNM degradation and TOC removal capacity. DFT calculation concluded that the electrons of d-orbital (Mn) and p-orbital (N) altered the electronic structure of biochar and enhanced the photoelectric performance. It was shown that Mn@N-Biochar caused negligible systemic inflammation and tissue damage when given orally in mice, and also did not alter cell death and ROS production in human lung, kidney, and liver cells, as compared with biochar. We are convinced that Mn@N-Biochar could enhance the photocatalytic degradation of antibiotics while maintaining biocompatibility, which could be a promising strategy for wastewater treatment.