Application Research Of Ultraviolet Combined Advanced Oxidation Process To Remove Trichloroanisole From Water

The presence of taste and odor?T&O?substances in the water will cause the water body to emit unpleasant odor,which will lead to the decline of water quality.The Advanced oxidation process?AOP?is a new process that degrades organic pollutants by generating free radicals with strong oxidation capabilities.The reaction process of this oxidation process is quite rapid and has a wide range of treatment of refractory organics.However,a single type of advanced oxidation process may have disadvantages such as low treatment efficiency,incomplete oxidation,and secondary pollution when processing certain odor-causing compounds.In this paper,ultraviolet light?UV?was introduced on the basis of the traditional chemical oxidation method,and ultraviolet combined with advanced oxidation process?UV-AOP?was used to conduct the oxidation experiment of the earthy and musty compound trichloroanisole?TCA?in water.The research results are as follows:The UV/hydrogen peroxide?UV/H₂O₂?process had the potential to control TCA pollution in water.With the help of hydroxyl radical??OH?quencher nitrobenzene?NB?,it was proved that?OH is the main reactive species produced in the UV/H₂O₂ oxidation system,and the degradation of 2,3,6-trichloroanisole?2,3,6-TCA?by UV/H₂O₂ was achieved by two ways,including UV photolysis and?OH oxidation.Increasing the concentration of H₂O₂ significantly improved 2,3,6-TCA removal.The degradation of 2,3,6-TCA via UV/H₂O₂ was found to result from a combination of dechlorination,hydroxylation and rearrangement reaction.The Vibrio fischeri luminescence experiment showed that the comprehensive toxicity of reaction solution showed a trend of increasing first and then decreasing as the degradation of 2,3,6-TCA continued.Trials with varying pH levels indicated that acidic or alkaline solutions gave higher degradation efficiencies.Both Cl^-and HCO₃^-inhibited 2,3,6-TCA oxidation during UV/H₂O₂process.Lower HA concentrations??1 mg/L?promoted 2,3,6-TCA oxidation while higher levels??3 mg/L?had a negative effect.Simulated degradation experiments in real-world water samples suggested that differences in the water matrix had varying degrees of inhibitory effects on the removal of 2,3,6-TCA.Compared with UV/H₂O₂,UV/Potassium peroxymonosulfate?UV/PMS?had its great advantage to a certain extent in 2,3,6-TCA abatement.It was proved that·OH and SO₄^?-were the dominant active species in 2,3,6-TCA degradation by UV/PMS by means of?OH quencher tert-butanol?TBA?and the dual quencher methanol?MeOH?of?OH and sulfate radical(SO₄^?-),and the relative contribution of·OH to the removal of 2,3,6-TCA was higher than that of SO₄^?-.Under the attack of the active species,2,3,6-TCA primarily underwent the reaction mechanism of dechlorination and hydroxylation and was transformed into two types of intermediate organic compounds containing chlorine.The comprehensive toxicity of the reaction solution was tested by the Vibrio fischeri luminescence experiment,and the data indicated that the comprehensive toxicity of the reaction solution also showed a trend of first increasing and then decreasing,and the increase was greater.Water quality parameters had different effects on of 2,3,6-TCA elimination in UV/PMS oxidation system.Increasing the pH of the reaction solution effectively enhanced the decontamination performance of UV/PMS process.Chloride and natural organic matter had different levels of inhibitory effects on2,3,6-TCA removal,whereas the effect of bicarbonate was negligible.The removal experiments under the actual water background showed that the removal process of 2,3,6-TCA by UV/PMS was continuously inhibited with the increase of the complexity of water quality conditions.