Photocatalysis of Rhodamine B in water using nanotechnology

Z. Yu, Z. Li
California State Polytechnic University, Pomona,
United States

Keywords: nanotechnology, photocatalysis, water


There are several techniques currently used for water organic contaminants removal, including Activated Carbon Adsorption, Chlorination, UV Photolysis, Ozonation, and Ferrate Oxidation. Although these techniques are useful in treating contaminated water, they have limitations in terms of removal completion, efficiency, rates, and operational costs. In addition, the methods for identification and quantification of both organic contaminants and the reaction products in water treatment are not well developed. We developed the method of combining the nanotechnology and the tandem water contaminants detection apparatus, namely Fourier Transform Infrared spectroscopy-Attenuated Total Reflectance (FTIR-ATR) and UV/Vis spectroscopy. This method would allow efficient, low cost removal of organic contaminants from water, with the removal process being constantly monitored for both contaminants and products. Our research consists of coating nanoparticles (graphite oxide) along with nano-inorganic materials (CdS) on a surface for photocatalysis of water contaminants under radiation of visible light. Rhodamine B has been used as a water contaminant surrogate to test our nano-technical treatment methods. Our preliminary results indicate that Rhodamine B in water undergoes photocatalysis with visible light in the presence of the nano materials based on the observations that the absorbance of Rhodamine B at  = 554 nm decreased and a new absorption peak at  = 497 nm emerged (Figure 1) during photocatalysis. Meanwhile the color of the sample solution changed from red to green-yellow after the cataphotolysis (Figure 2a). Furthermore, in the presence of hydrogen peroxide the Rhodamine B sample solution became colorless after 72 hours of visible light cataphotolysis (Figure 2b). Our kinetics data also suggest that the photocatalytical decay of Rhodamine B follows first order chemical kinetics behavior (Figure1). The degradation rate and products of the Rhodamine B photocatalysis in water will be discussed.