Biomass-Derived N-Doped Ordered Mesoporous Carbon-Supported Gold Nanoparticles: An Efficient Catalyst for the Reduction of Nitroaromatic Pollutants

N-Doped highly ordered mesoporous carbon (N-OMC) material was synthesized by impregnation of egg-yolk biomass into the SBA-15 template, followed by carbonization at 700 °C under an atmosphere of N₂, and removal of the SBA-15 silica moiety with an alkaline aqueous solution under heating conditions. Au nanoparticles were decorated on the surface of the N-OMC material by chemical reduction of NaAuCl₃ using NaBH₄ in the presence of N-OMC. The synthesized Au@N-OMC was characterized by XRD, SEM, TEM, XPS, BET and EDS, which showed the successful decoration of Au nanoparticles on the surface of mesoporous carbon. Au@N-OMC showed high catalytic activity in the remediation of nitroaromatic pollutants from wastewater by reduction to the corresponding aniline derivatives. The kinetics of the Au@N-OMC-catalyzed reduction of 4-nitrophenol was investigated, which showed that the reduction in the presence of excess amount of NaBH₄ reductant, followed pseud-first-order kinetics. Three methods were carried out to investigate the reusability of the Au@N-OMC catalyst, which showed that the recycled catalyst could be reused several times without significant changes in catalytic activity. The leaching test was also performed by separating the Au@N-OMC catalyst at the half time of the reaction, revealing the heterogeneity of the catalyst.