Photochemical reduction of chromium(VI) by phenol and its halogen derivatives

Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe2O4/CdS

“…At this level, the photocatalysis has proved to be quite interesting in the elimination of chromate [8] which can comply with the World Health Organization instructions: to decrease the maximal concentration at less than 5 ppm [8]. Cr(VI) is reduced by photolysis [9] or photoelectrochemically to less hazardous oxidation states namely trivalent state [10]. Cr(III) is readily precipitated because of the low solubility of Cr(OH) 3 and can be either chelated by organic molecules or adsorbed by various substrates [11].…”

Homogeneous photocatalysis by transition metal complexes in the environment

“…First of them consists in thermal reduction of dissolved Cr(VI) to Cr(III) mostly by reducing agents such as S 2− , Fe(II) or some organic compounds [133]. The second pathway includes photochemical reduction of Cr(VI) in the organic matter systems [134][135][136][137].…”

Simultaneous photocatalytic reduction of Cr(VI) and oxidation of bisphenol A induced by Fe(III)–OH complexes in water

“…In the two-component system with Cr(VI) and BPA, the photodecomposition rates of Cr(VI) and BPA are low; both of the decomposition efficiencies are about 20% after 120 min irradiation. In this system, Cr(VI) reduction is described via pho- toinduced electron transfer (PET) [13]. The reduction of Cr(VI) is accompanied by simultaneous oxidation of BPA, which plays a role of sacrificial electron donor.…”