Simultaneous reduction of Cr (VI) and degradation of azo dyes by F-Fe-codoped TiO2/SiO2 photocatalysts under visible and solar irradiation

Abstract

A new TiO2/SiO2 photocatalyst codoped with fluorine and iron was synthesized using the sol–gel process and immobilized onto glass beads by coupling two methods of dip coating and heat attachment. The prepared samples were characterized by XRD, FTIR, DRS-UV–vis, FESEM, EDX, TEM, and N2 adsorption–desorption analysis. The effective parameters of pH, flow rate, and photoreactor vessels’ angle against solar irradiation on degradation performance were optimized. Subsequently, the photocatalytic activity of the prepared nanocomposites was investigated in an innovative fabricated photoreactor using a four-component pollutant mixture of Cr (VI), basic red 29, basic blue 41, and basic yellow 51 under visible and solar irradiation. Furthermore, the effectiveness of photoreactor performance was assessed under various outdoor climate conditions as natural irradiation sources. Consequently, UV–vis spectrophotometry results showed significant efficiency of photocatalytic removal of the pollutant mixture. TOC results of 74.39% and 78.04% for removal of organic content of the sample under visible and solar light, respectively, were also confirmed the great capability of the designed system for the simultaneous removal of some hazardous inorganic and organic contaminants under natural light sources.