Single-atom Mn anchored on N-doped graphene oxide for efficient adsorption-photocatalytic degradation of sulfanilamide in water: Electronic interaction and mineralization pathway

Synergy between adsorption and photocatalysis provides an ideal green technology to treat antibiotic pollution in water. In this study, single-atom Mn anchored on N-doped graphene oxide (Mn-NGO) was synthesized for enhanced adsorptive-photocatalytic removal of aqueous sulfanilamide (SNM) and the corresponding mechanisms were revealed. The Mn-NGO had better performance of SNM degradation and TOC removal than GO and NGO. Density functional theory (DFT) calculation showed that the electrons of d-orbital (Mn) and p-orbital (N) upgraded the electronic structures of GO of the Mn-NGO to interact with amino and aromatic rings of SNM, increasing the adsorption and polarizing of SNM. Furthermore, more hydroxyl and superoxide radicals were observed on Mn-NGO, leading to the generation of key reaction intermediates of 2-aminohydroquinone and benzenesulfonic and thus subsequently opening loops and mineralizing SNM. In addition, Mn-NGO effectively removed SNM in different types of water systems (e.g., lake water, tap water, and deionized water) through synergistic adsorption-photocatalytic degradation.

Automated summary

The synergy between adsorption and photocatalysis provides an ideal green technology for treating antibiotic pollution in water. In this study, single-atom Mn anchored on N-doped graphene oxide (Mn-NGO) was synthesized and showed enhanced adsorptive-photocatalytic removal of aqueous sulfanilamide (SNM). The mechanisms behind the enhanced performance were revealed, including upgraded electronic structures, increased adsorption and polarizing of SNM, and the generation of key reaction intermediates.