Valorization of algal biomass to synthesize heterogeneous gCN-Biochar photocatalyst for the treatment of industrial wastewater using photocatalysis-persulfate oxidation process.

Textile wastewater, heavily contaminated with organic dyes, is generating severe problems to environment and human health. The implementation of gCN with biochar (gCN-BC) for the treatment of textile wastewater is less effective due to the limited adsorption capacity and slower degradation kinetics. To tackle these problems, peroxydisulfate (PDS) is integrated with gCN-BC photocatalyst to enhance the process efficiency and kinetics. The synthesized gCN-BC-5 composite shows higher separation of charge carriers, light absorbance, and lower energy bandgap (2.62 eV). The results of photocatalytic degradation and rate constant are enhanced up to 99.9 % and 0.041 min using gCN-BC-5 with PDS as compared to without PDS (96.8 % and 0.028 min, respectively). The radicals (SO,O, and OH) are responsible to improve the degradation process efficiency and kinetics. The reusability of optimized sample indicates that gCN-BC-5 is stable and effective up to five cycles. The gCN-BC-5 composite attains highest adsorption (70.9 %) when compared to BC (62.3 %) and pure gCN (27.1 %). The well-fitted models of adsorption (Pseudo-Second-Order and Freundlich) confirm the favorable, chemical, and multilayered adsorption process. The coupling of gCN-BC-5 with PDS is effective, efficient, and stable process to enhance the kinetics and degradation of textile wastewater.