Lignin-modified graphitic carbon nitride nanotubes for photocatalytic HO production and degradation of brilliant black BN.

As a renewable aromatic compound with enormous production potential, lignin has various potential high-value utilization pathways, but the success achieved in the field of photocatalysis is limited. Herein, this work prepares a new type of photocatalyst by modifying Graphitic Carbon Nitride Nanotubes (CNT) with self-assembled lignin nanospheres for the photocatalytic production of HO and the degradation of azo dyes. Under light conditions, lignin enhances the production of HO through oxygen reduction and collaborates with carbon nitride tubes to generate O and O. Furthermore, carbon nitride tubes form electron-rich regions with lignin, promoting the transfer of electrons from adsorbed aromatic pollutants to this region, thereby facilitating their degradation. The experimental results indicate that the addition of 5 % lignin significantly enhances the photocatalytic degradation efficiency of azo dyes, with a degradation rate 1.87 times higher than that of the original carbon nitride tubes. Furthermore, CNL also have excellent degradation ability to pollutants in actual wastewater. This study provides new insights and prospects for the high-value utilization of lignin, enabling it to be used as a photocatalytic co-catalyst to participate in the photocatalytic degradation of environmental pollutants.