Photocatalytic performance of nickel doped zinc chromate chitosan derived photocatalyst for haematoxylin dye and phthalic acid removal: Structural, optical and electrochemical properties.

The elimination of recalcitrant organic pollutants such as Haematoxylin dye (HEM) and Phthalic acid (PA) from aqueous matrix is currently urgent need due to its harmful impacts on aquatic life and possible carcinogenic consequences on human health. Here in this study, we developed facile green synthesis of nickel doped zinc chromate chitosan derived Ni@ZnCr2O4/CS photocatalyst for removal of HEM and PA pollutants. The synthesized Ni@ZnCr2O4/CS were characterized by different techniques such as P-XRD, HR-TEM, BET, FT-IR, TGA, XPS, and UV-Vis DRS. This heterointerface exhibited retained crystallinity, higher surface area, greater thermal stability, lower band gap and effective interfacial charge separation which make it efficient photocatalyst. The maximum degradation rate found to be 97% and 95% for both HEM and PA pollutants. It has 2 times higher rate constant to parent composites and follow 1st order kinetics with Langmuir isotherm adsorption model for both HEM and PA pollutants. Mott-Schottky analysis, supporting an n-type semiconductor. Interfacial resistance was reduced, according to (FL and EIS). Radicals of the ·OH and •O2- types were shown to be the main reactive species that control the degradation process using radical scavenging tests. The mineralization rate percentage found to be 81.17 and 80.81 for the HEM and PA pollutants. The composite show remarkable stability, >86% degradation of both pollutants up to 7th cycles confirmed by P-XRD pattern. This approach has the potential to greatly enhance environmental remediation and wastewater treatment in a sustainable way.