Survey of Nitrate Removal Method from Aqueous Solutions Using Titanium Dioxide Nano-Photocatalyst

Background & objectives: Because of its very high solubility, nitrate penetrates easily into soil and underground waters. Surface waters such as lakes, reservoirs, and rivers are exposed to nitrate pollution. Photocatalytic processes have a high potential for nitrate removal due to complete oxidation, lack of formation of multi-cycle metabolites and the availability of catalysts. The purpose of this study was to investigate the nitrate removal from aqueous solutions using photocatalyst of titanium dioxide nanoparticle under the influence of ultraviolet light (UV). Methods: This laboratory-experimental study was carried out as discontinuously using a photocatalytic process in a reactor with volume of 1-liter, containing 250 ml of a sample with radiation source of UVC ultraviolet lamp and a power consumption of 9W. The statistical method of the CCD response level, one of the standard methods of RSM, was used to investigate the parameters of pH, titanium dioxide nanoparticle, nitrate concentration and contact time. Results: The results showed that nitrate removal from aqueous solutions was influenced by factors such as exposure time to ultraviolet light, nitrate concentration, nanoparticle content and pH. The optimum conditions for nitrate removal, based on the appropriate model, were obtained from the response level statistical method including 0.55 g/l titanium dioxide nanoparticle, nitrate concentration of 35.15 mg/l, pH=5 and contact time of 50.22 minutes equal to 62.59%. Conclusion: The process used in this study, according to the desired conditions, is able to remove nitrate from aqueous solutions, and changing the laboratory conditions can be effective in it eliminating. This process can be recommended as an economic and practical solution to nitrate remove from drinking water.