Photocatalytic Reduction of Aqueous Cr(VI) with CdS under Visible Light Irradiation: Effect of Particle Size

Abstract

Stringent environmental standards have made the removal of Cr(VI) from water an important problem for environmental scientist and engineering. Heterogeneous photocatalysis using suspended photocatalyst is an interesting technique to consider for this application. In this work, the influence of particle size of suspended CdS on the photocatalytic reduction of aqueous Cr(VI) ion was investigated. The efficiency of Cr(VI) reduction was monitored through UV-visible analysis. The experimental results showed that the nanoparticle size has a dramatic effect on the adsorption and reduction of Cr(VI). As surface area increased from 44.2±0.6 to 98.7±0.5 m 2 /g due to particle size reduction, the rate of Cr(VI) reduction nearly doubled in the first 20 min of visible light irradiation. The results evidenced the inverse relationship between the apparent reduction rate constant and the CdS particle size. Conversely, the half-life (t1/2) period of the photocatalytic reduction has a direct relationship with CdS particle sizes.

Carbon Microspheres with Cr(VI) Adsorption Performance were Prepared by In-situ Hydrothermal Carbonization Method

“…Fitting the adsorption behavior of hexavalent chromium on HTC using pseudo-firstorder kinetic and pseudo-second-order kinetic models (Equations ( 3) and ( 4) [33,34]). The Langmuir adsorption isotherm equation (Equation ( 5) [34][35][36]) and the Freundlich adsorption isotherm equation (Equation (6) [21,30]) were used to describe the monolayer or multilayer adsorption process on the surface of HTC.…”

Solid-phase Synthesis of Visible-light-driven BiVO4 Photocatalyst and Photocatalytic Reduction of Aqueous Cr(VI)

“…Therefore, it is urgently develop eco-nomical and environmental-friendly methods of removing the Cr(VI) wastewaters. Photocatalytic reduction of Cr(VI) into Cr(III) has now been proven as an effective procedure for treating Cr(VI) wastewaters [7][8][9][10][11][12] due to its high efficiency, low cost, environmental friendly, and exploitation of solar energy. Consequently, it is desirable to develop new visible-lightresponsive semiconductor photocatalysts cater to industrial application of photocatalytic technology treat large scale Cr(VI) wastewaters, and make full use of solar energy.…”