Phthalic acid modified TiO2 and enhanced photocatalytic reduction activity for Cr(VI) in aqueous solution

The photocatalytic reduction of Cr(VI) on TiO2 nanoparticle modified with phthalic acid, which was prepared through a chemisorption method, has been investigated under ultraviolet light irradiation. This study found that the adsorption of phthalic acid onto the surface of TiO2 nanoparticle resulted in the formation of a surface-modified complex. The interaction of TiO2 with phthalic acid was characterized by various spectroscopic methods including diffuse reflectance UV–vis, infrared, fluorescence spectra, and X-ray diffraction (XRD). The results indicated that the recombination of charge carriers was effectively suppressed due to the modification of phthalic acid on the surface of TiO2. In addition, the modified TiO2 resulted in enhanced photocatalytic reduction activity for Cr(VI), which might be attributed to the effective separation of electron–hole pairs.