The Study On Photochemical Degradation Of Dichlobenil In Water

This paper established a detection method in water environment hydroxyl radical content and diuron nitrile o-dichlorobenzene GC-MS detection method-carbonitrile.Experimental research and analysis of the indoor high-pressure mercury lamp?HPML?,natural light?sunlight?and three indoor UV lamp light source dichlobenil photochemical degradation;study analyzed under the same conditions proanthocyanidins?Oligomeric Proanthocyanidins,OPC?,H2O₂ and nano TiO₂ Photochemical degradation effect oxabetrinil enemy and after comparison and analysis of the product proanthocyanidins promote photochemical mechanism of dichlobenil degradation of nitrile solution.Dichlobenil photochemical degradation results show that dichlobenil indoors high pressure mercury lamp?HPML?,sunlight?natural light?and indoor UV lamp three light irradiation degraded reaction results: K?sunlight?<K?UV light?<K?high pressure mercury lamp?.Diuron in aqueous systems nitrile,three light enemy oxabetrinil photosensitizing efficiency:high-pressure mercury lamp> the ultraviolet> sunlight.Photochemical degradation product of diuron nitrile via GC-MS and HPLC chromatographic analysis may determine o-chlorobenzonitrile?2-Chlorobenzonitrile?and benzonitrile?Benzontrile?two products.Dichlobenil?DCBN?in the illumination conditions can itself photodegradation and reaction process in enemy grass nitrile molecules in the light illumination conditions by energy transfer to by the steady state of dichlobenil molecular changes become chemically active excited state dichlobenil,then occurred in a series of subsequent reaction.Under the condition of light,the water body is formed with strong oxidizing hydroxyl radical.On the benzene ring of Cl 2 position will be replaced by hydroxyl and produce a Cl-and 2-hydroxy-6-chloro benzonitrile,but it is not stable,oneself also will light degradation occurs,generating a nitrile o-dichlorobenzene.Addition of OPC could accelerate the degradation of 2-hydroxy-6-.It was difficult to find in the liquid chromatography of the DCBN-OPC photo degradation system.In the light of illumination conditions adjacentdichlorobenzonitrile will in accordance with the reaction mechanism continue to react under the system of hydroxyl radicals,2-chloro-benzonitrile benzene molecule molecular chlorine will continue to occur hydroxyl substitution reaction,generate benzonitrile.The addition of OPC and TiO₂ could greatly promote the photochemical degradation rate of the.OPC degradation enemy grass nitrile experiments show that OPC enemy grass nitrile degradation of promoting effect is increased with the concentration of OPC increased first and then decreased.The experimental results show that the degradation effect is best when the concentration ratio of DCBN to OPC is 50 mu mol/L:250 mu mol/L.Determination of hydroxyl radical results showed that nano TiO₂ and H2O₂ in the light illumination conditions,will produce a large number of hydroxyl radicals,hydroxyl radical with strong oxidation,can oxidize and decompose the enemy grass nitrile,prompted on the benzene ring of the chlorine atoms from organic chlorine to inorganic chlorine transformation.OPC molecules containing large amounts of phenol hydroxyl,in light according to the oxidation effect under the condition of the molecules in the O-H tendon rupture,the occurrence of dehydrogenation reaction to generate a large number of strong reduction of[H],hydrogen radicals will neutralization reaction system of hydroxyl radical,reduce the oxygen reaction system.On the other hand,[H] can participate in the reaction system.As a result,the PNDA/OPC/DCBN photolysis system increases with the increase of the time of illumination.OPC photolysis system,DCBN+OPC will be used as a [H] donor and the reaction of the substitution reaction of the molecule of the enemy and the grass,to promote the conversion of organic chlorine to inorganic chloride.OPC changed with addition of dichlobenil oxyhydroxide removal chlorine reaction mechanism,formed a new substitution of hydrogen reductive dechlorination of chlorine reaction mechanism,reduce the enemy grass nitrile photochemical degradation steps,greatly accelerated the enemy grass nitrile photochemical degradation rate.The photochemical degradation of diuron?DCMU?and pentachlorophenol?PCP?in aqueous solution showed that proanthocyanidins in aqueous solution can be greatly suppressed diuron and PCP photochemical degradation.