Remove Organic Pigments from Wastewater in Range of Visible Light

Researchers from Iran University of Science and Technology used nanotechnology and succeeded in the production of a photocatalyst that is able to purify industrial wastewater in the range of visible light.
This photocatalyst is more successful in the removal of a special type of cancerous pigment from water than other commercial photocatalysts in the market for the purification of water.
In this research, the photocatalytic performance of two sample groups of niobium pentoxide with porous and bulk structure was investigated and compared while the samples were synthesized through two different methods. Among the investigations carried out in this research, mention can be made of the comparison between photocatalytic performance of mesoporous samples and bulk ones, and commercial samples in dye removal of colorful wastewater containing malachite green pigment under the radiation of ultraviolet and visible light and other conditions imposed to the reaction system.
The results showed that the sample produced at lower temperature (calcination temperature) has the strongest ability to remove dyes from malachite green wastewater among all other samples. Therefore, the reduction in the energy required for the production of a sample with optimum performance is one of the positive results of the research. The more important characteristic is the strong performance of the optimum sample under visible light that includes a wide range of sunlight radiation wavelengths.
Commercial titanium oxide photocatalyst is active only under ultraviolet radiation. Therefore, highly consuming energy and harmful radiation of ultraviolet is required for the use of this semi-conductive compound in the removal and degradation of organic pollutants in the wastewater of various industries. In the contrary, the produced photocatalyst in this research has desirable activity and performance in the range of visible light. Reduction in the energy consumption and the removal of harmful effects of ultraviolet light are among the important achievements in this research, which are caused by the appropriate performance of the catalyst in the range of sunlight radiation.
Results of the research have been published in Ceramics International, vol. 40, issue 7, January 2014, pp. 9817-9829.