Study On The Efficiency Of Chlorine Resistant Bacteria Inactivated And TCE Degraded By Fenton-like

Water supply network is an important part of urban water supply system. After long term operation of water supply network, because of synthetic action of physics, chemical, electrochemistry and microbiological action, along the inner wall of the pipeline will form an irregular ring, that is, the growth ring will form along the inner wall of the pipeline. The growth ring is composed of rust, sediment and biological membrane and the main constituents include goethite, lepidocrocite, Fe S and so on. At the same time, many kinds of bacteria, such as Escherichia coli, iron bacteria, Pseudomonas and so on, exist in growth ring.Trichloroethylene is a water-immiscible and volatile chlorinated organic compound. With good chemical stability and thermal stability in the environment, Trichloroethylene is hard to be broken down or degraded chemically. Trichloroethylene enters natural environment through leakage of pipe. Trichloroethylene may enter the pipe network through the pipe leakage, resulting in pipe network water pollution.Ferric chloride as precursors, we synthesize goethite successfully by controlling reaction conditions in the laboratory. With larger specific surface area(146.8477 m2/g), synthesized goethite has a certain ability of adsorption and adsorption capacity. In the paper, goethite as iron source and hydrogen peroxide constitute the Fenton-like system. We study the effect of the system on disinfection of chlorine resistant bacteria and catalytic degradation of TCE.The Fenton like system has obvious inactivated effect on the typical chlorine resistant bacteria, and the inactivated effect is related with catalyst and hydrogen peroxide dosage.The experimental analysis demonstrates that the optimal p H=3, the optimal dosage of catalyst and hydrogen peroxide are 0.10mol/L and 1% respectively.The Fenton-like system has strong oxidation ability. Fenton-like responds 8 hours, the degradation rate of TCE in water can reach 97.38%. The degradation effect of TCE relates with goethite dosage, hydrogen peroxide dosage and initial p H value of solution. Through comparative analysis, we find that influence degree of initial p H value of solution is the biggest; goethite reagent is the second; influence degree of hydrogen peroxide dosage is the smallest. Besides, the experimental analysis demonstrates that the optimal p H=3, the optimal dosage of catalyst and hydrogen peroxide are 3.33g/L and 1.15 respectively.The removal of TCE by the Fenton-like system is second order reaction. The removal of TCE is carried out by free radical through multistep. First, in the acidic conditions, goethite dissolves and ionic iron appear in solution, which catalyzes hydrogen peroxide to produce a variety of oxidative free radicals and nucleophilic anion. And then hydroxyl radical reacts with TCE in a series of addition reaction and dehydration reaction. In the end, the free radical anion reacts with TCE in dechlorination reaction; TCE is degraded and generate water and carbon dioxide, and the chloride ion is generated simultaneously.