Study On Oxidation Of Aniline And Arsenic By Transition Metal Activated BAP System

Aniline and arsenic are two pollutants that are widely present in groundwater and have obvious damage to the environment.In order to effectively deal with these two pollutants,this article uses two transition metals,Mn^Ⅱ-BAP and Co^Ⅱ-BAP,in combination with BAP.The system oxidizes aniline and arsenic,and systematically explores the oxidation effect,the factors affecting the oxidation effect,and the main active substances of oxidation.In the process of aniline oxidation in Mn^Ⅱ-BAP system,the optimal conditions and oxidation mechanism of aniline oxidation in Mn^Ⅱ-BAP system were explored through kinetic experiments and masking experiments.The experimental results show that the Mn^Ⅱ-BAP system can oxidize 99.5%of aniline within 10 minutes,with a reaction rate constant of 5.30×10^-1 min^-1,at pH 8.5,[HCO₃^-]=0.2 M,[Mn²⁺]=0.1 mM,[H₂O₂]=13mM,the Mn^Ⅱ-BAP system has the best oxidation effect on aniline.The synergy between Mn²⁺and HCO₃^-will cause the concentration of HCO₃^-and Mn²⁺in the reaction system to have an important impact on k_obs.The masking experiment on the active species in the Mn^Ⅱ-BAP system shows that it is effective in degrading aniline.The main active species is superoxide radicals instead of OH·,Mn（IV）,¹O₂,and MnO₂⁺-（HCO₃^-）_n is the main active species for aniline oxidation in the Mn^Ⅱ-BAP system.The reaction mechanism involved in the degradation of aniline in the Mn^Ⅱ-BAP system can be roughly divided into three steps,that is,Mn^Ⅱ-（HCO₃^-）_n decomposes H₂O₂ and generatesO₂^·-,and then O₂^·-reacts with Mn^Ⅱ-（HCO₃^-）_n to further generate MnO₂⁺-（HCO₃^-）_n and then MnO₂⁺-（HCO₃^-）_n degrade aniline.Gas chromatography mass spectrometry combined with analysis of degradation products of aniline showed that aniline was oxidized to nitrobenzene,azobenzene,azobenzene oxide,o-phenylenediamine and phenazine.In the experiment of Co^Ⅱ-BAP system oxidation of As（Ⅲ）,the ability of Co^Ⅱ-BAP system to oxidize As（Ⅲ）in the best conditions and the specific oxidation of As（Ⅲ）in Co^Ⅱ-BAP system were explored through kinetic experiments and masking experiments.mechanism.Experiments show that the Co^Ⅱ-BAP system can oxidize 96.9%of As（Ⅲ）within 10 minutes.Choose pH=8.5,[HCO₃^-]=0.2 M,[Co²⁺]=0.2 mM,[H₂O₂]=10 mM as the reaction conditions.The masking experiment on the active species in the Co^Ⅱ-BAP system shows that the active species that plays a major role in the oxidation of As（Ⅲ）are superoxide radicals instead of OH·and ¹O₂,while CoO₂⁺-（HCO₃^-）_n and Co^Ⅲ-OOH-（HCO₃^-）_n is the main active substance for the oxidation of As（Ⅲ）in the Co^Ⅱ-BAP system.