Potential application of MoO3 loaded SBA-15 photo-catalyst for removal of multiple organic pollutants from water environment

A photo-catalyst of mesoporous silicate SBA-15 doped with 15%MoO3 was synthesized by modified sol-gel process and then characterized by SBET, XRD, HRTEM/EDX, TGA and optical techniques. The photo-catalytic performances of 15%Mo/SBA-15 were tested in the photo-remediation of wastewater composed of multi-organic pollutants (i.e., aromatics, phenols, and dyes) at different light sources of visible (400 nm), UVB (316 nm)and UVC (254 nm) irradiation. The photo-catalytic activities of the 15%Mo/SBA-15 were considerably greater under UVC irradiation, which is coincident with 15%Mo/SBA-15 calculated band gap of 3.5 eV. Further, wastewater treatment rate was ranked in the order of aromatic > phenolic > dyes with the rate of 95%, 69%, and 14%, respectively after 120 min UVC irradiation time. A statistical analysis, using both parametric (one way ANOVA) and nonparametric (Kruskal-Wallis) methodologies, were developed to validate the experimental comparison between neat SBA-15 and 15%Mo/SBA-15 based on structural properties, light intensity and the type of organic contaminants are the key factors influencing the photo-catalytic degradation rate. The kinetic rate of the wastewater photo-catalytic remediation was found to be ranked in the order of benzene > anthracene > pyrene > naphthalene within aromatic contaminants, hydroxyphenyl ≈ chlorophenols > phenol within the phenolic group, and no significant difference between methyl orange and methyl red within dyes contaminants over 15%Mo/SBA-15. Results suggested that the developed 15%Mo/SBA-15 could be used as efficient photocatalysts for the treatment of petroleum and petrochemical wastewater with aromatic and phenolic hazardous, but not efficient for the treatment of textile wastewater pollutants.