Photocatalytic Degradation Of Methylene Blue Using Plasmonic Materials

The photocatalytic method due to easy to control, mild reaction conditions,efficient degradation of organic pollutants, without secondary pollution and otheradvantages, has a major significance in the application of industrial wastewatertreatment. Most of catalytic light source is xenon lamp or high-pressure mercury lampand TiO2is the representative of the material. The traditional sources have issues oflow utilization rate and large energy loss with ordinary light. Representative of thetitanium dioxide photocatalytic material because the bandgap quantum utilization ratealso greatly limits the application of photocatalytic. One of the new, safer, andenergy-efficient alternatives for the traditional lamps is laser. As laser is a coherent,monochromatic, and highly directional source of light, the incident photons can beabsorbed more efficiently by the photocatalyst, as compared with absorption affectedby use of broadband spectral sources such as lamps. Titanium dioxide as arepresentative of the traditional photocatalytic materials because the band gap is wideand quantum utilization is low, which greatly limits the range of applications. Inrecent years, plasmonic photocatalyst materials based on the silver/silver halidebecome a hot topic resulting from improving the photocatalytic properties of thesystem. In this paper, visible laser diode was used, nano Ag/AgCl and Ag/TiO2as acatalyst for studies of methylene blue (MB) photocatalytic degradation. It will providea theoretical basis for industrial organic wastewater treatment.Ag/AgCl and Ag/TiO2plasmonic photocatalyst materials in this article wereprepared by co-precipitation; using scanning electron microscopy to characterize thematerial and found that both nanoparticles; tested by degradation of methylene bluesolution for both photocatalytic performance, show that Ag/AgCl and Ag/TiO2invisible light have good catalytic activity and Ag/AgCl has better catalyticperformance.We study the degradation and decolorization of MB with Ag/AgCl in the visibleregion through illumination time, type of light source, light intensity, concentration ofMB, and amount of Ag/AgCl catalyst, initial pH and other factors. It found that whenreaction time was10min, Ag/AgCl catalyst can complete bleaching MB, and the degradation rate was90.82%under the conditions of the experiment the optimalsetting, including visible laser diode was at a wavelength of443nm, the output powerof1.15W. After reused many times, the catalyst still showed efficient and stablecharacteristics.Finally, we used co-precipitation method, by adjusting the experimental variationprecursor concentration of silver nitrate (0.1-0.6mol/L) and the amount of surfactantpolyvinyl pyrrolidone (PVP) to achieve the Ag/AgCl material morphology control.Scanning electron microscopy examination found that the catalyst particle sizes weredifferent, besides, surface active agent made the particle size become smaller, and auniform morphology. Particle size of the catalyst precursor at a concentration of0.4mol/L was the minimum and obtained the maximum catalytic activity.