Modified PVA-alginate encapsulated photocatalyst ferro photo gels for Cr(VI) reduction.

In this study magnetic separable photocatalyst beads containing maghemite nanoparticles (γ-Fe(2)O(3)) in polyvinyl alcohol (PVA) polymer were prepared and used in the reduction of Cr(VI) to Cr(III) in an aqueous solution under sunlight. The unique superparamagnetic property of the photocatalyst contributed by the γ-Fe(2)O(3) and robust property of PVA polymer allow the magnetic beads to be recovered easily and reused for at least 7 times without washing. The concentration of γ-Fe(2)O(3) was varied from 8% (v/v) to 27% (v/v) and the results revealed that the beads with 8% (v/v) γ-Fe(2)O(3) exhibited the best performance where Cr(VI) was reduced to Cr(III) in only 30 min under sunlight.

Kinetic and regeneration studies of photocatalytic magnetic separable beads for chromium (VI) reduction under sunlight.

Physical adsorption and photocatalytic reduction of Cr(VI) in magnetic separable beads were investigated. In order to elucidate the kinetics of photocatalytic process, operating parameters such as catalyst dosage and the initial concentration were examined in detail. It was observed that the reduction rate of Cr(VI) increased with an increase in the catalyst loading, as this translated into an increase in the number of available active sites.

Photocatalytic magnetic separable beads for chromium (VI) reduction.

Magnetically separable photocatalyst beads containing nano-sized iron oxide in alginate polymer were prepared. This magnetic photocatalyst beads are used in slurry-type reactors. The magnetism of the catalyst arises from the nanostructured particles gamma-Fe(2)O(3), by which the catalyst can be easily recovered by the application of an external magnetic field.