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Various semiconductors have been used as photocatalysts for removal of different dyes from their aqueous solutions. Zinc sulphide semiconductor is used in the present investigation as a photocatalyst for the removal of rose Bengal dye. Effect of different parameters, which affect the rate of reaction; like pH, concentration of dye, amount of semiconductor and light intensity have been studied. A mechanism has also been proposed in which hydroxyl radicals are shown as an active oxidizing species.

Different methods of wastewater treatment are being used for the removal of dyes from their solution, but in most of the cases, either homogeneous catalysts or different adsorbents are used. These methods have their own merits and demerits. In the present work, antimony trisulphide was used as a heterogeneous catalyst. The effects of different parameters on the rate of the reaction were observed, such as pH, concentration of dye, amount of semiconductor and light intensity. A tentative mechanism is proposed in which the role of hydroxyl radical as an active oxidizing species is shown for degradation of Naphthol green B. [ABSTRACT FROM AUTHOR]

Different methods have been adopted for the removal and degradation of dyes from effluents of textile, dyeing and printing industries. These methods have their own merits and drawbacks. In the present investigation, bismuth sulfide has been used as a photocatalyst for the degradation of rose Bengal. The effect of different parameters like the pH, concentration of dye solution, amount of semiconductor and light intensity on the rate of reaction has been investigated. The reaction follows pseudo-first order kinetics. The optimum conditions were obtained as: [rose Bengal] = 1.60⋅10-5 M; Bi2S3 = 0.10 g; pH = 8.5, and light intensity = 50.0 mW⋅dot;cm-2. The rate constant was 4.68⋅dot;10-5 sec-1. A mechanism has been proposed for the degradation of rose Bengal involving hydroxyl radicals. [ABSTRACT FROM AUTHOR]

Abstract: Solar desalination is gradually emerging as a successful renewable energy source of producing fresh water from seawater or brackish water by utilizing the greenhouse effect of solar energy. To enhance the overall efficiency of conventional basin type solar still, different semiconducting oxides like CuO, PbO2 and MnO2 have been utilized as photocatalysts. It is observed that metal oxides not only improve the efficiency of the process but the rate of production of desalinated water was also increased to a remarkable extent. The water quality for its various parameters like pH, TDS, etc. are analyzed (for raw and desalinated water). [Copyright &y& Elsevier]