Study On Solar Photocatalytic Degradation And Frozen Treatment Of Bromamine Acid Wastewater

Both the solar energy and cold energy are kinds of renewable natural energy which have great potentialities. It has been one of current research focuses on resolving environmental pollution and energy crisis simultaneously by the utilization of natural energy.Heterogeneous photocatalysis is a novel wastewater treatment technology utilizing the solar energy. Modification and coupling technology for TiO₂ photocatalyst was researched to extend the spectral response range and enhance the catalytic activity. Lacunaris coupled CdS/TiO₂ photocatalyst which could be activated by visible light and easily separated from liquor was prepared by coupling CdS with lacunaris TiO₂ by sol-gel process. Morphology of photocatalyst was characterized by SEM and XRD. The results showed that the pectral response range of photocatalyst was expanded by coupled CdS. The optimal preparation conditions were CdS doping ratio 3%, calcining temperature 700℃, calcining time 3h, and alkali marinating time 20h, and the particle size of lacunaris coupling CdS/TiO₂ photocatalyst was 2⁴μm.The photocatalytic degradation of bromamine acid was investigated under sunlight, and the influence of light pattern, initial pollutant concentration, photocatalyst dosage, pH value and inorganic ion concentration were discussed. The deactivation mechanism of photocatalyst was explored and kinetic model of degradation was built. The results suggested that bromamine acid was degraded for 6h under solar light with TOC removal above 90%, and the optimal degradation condition was dosage of photocatalyst 2g/L and pH value 10 for the bromamine acid solution of 30mg/L. Existence of Cl- and SO42- was disadvantaged to degradation reaction. Na+ and Ca2+ had little effects on degradation reaction. Trace Fe3+ could enhance the degradation efficiency, but Cu2+ could decrease the activity of photocatalyst.Cold energy can be utilized to remove pollutants from wastewater by frozen-thaw technology. In this paper, frozen separation technology was studied under artificial and natural conditions respectively. The affection of freezing temperature, time and initial pollutant concentration was studied. Freeze separation rules and separate layer mechanism were investigated. According to the specialties of high salinity and orgnic pollutants in dye wastewater, it was separated and treated by combined freeze- photocatalysis technology. In addition, cleaner production is one of the most important measures to resolve environmental pollution. In this study, Ullmann condensation reaction of bromamine acid was improved by the application of a new type of solid-acid catalyst. Ullmann condensation reaction of bromamine acid was catalyzed by the catalytic system of strong acid ion exchange resin-ethanol-copper instead of traditional sulfuric acid-water-copper. In the new catalytic system, high saliferous wastewater discharge was greatly reduced, realizing the recycling of resource.