Photocatalytic Reduction of Cr(VI) with Titanium Dioxide Supported on SiO₂-Coated Magnetite Particles

ABSTRACT: Hexavalent chromium compounds are considered carcinogenic to humans. Its reduction to Cr(III), which is relatively non-toxic and an essential nutrient for humans, is a critical process. Heterogeneous photocatalysis with TiO₂ is a promising remediation method with satisfactory results. However, this semiconductor cannot be released into an aqueous media because it is dangerous to multiple forms of life. The removal of TiO₂ requires laborious and costly methods, so a practical method is needed. One of these alternatives is to immobilise TiO₂ on magnetic particles to facilitate its extraction. In this work, the photocatalytic reduction of Cr(VI) is carried out with TiO₂ immobilised on SiO₂-coated magnetite particles, called FST-5. As a sacrificial reduction agent, EDTA (Ethylenediaminetetraacetic acid) was used with satisfactory results. When both are combined, a significant decrease in the aqueous Cr(VI) amount is observed. It indicates its potential application for the remediation of water courses contaminated with this heavy metal.