Oxidation Of Aluminum Diethylphosphinate By Microwave-induced Catalysis Of H₂O₂,Na₂S₂O₈ With Fe₃O₄-CuO@AC

Aluminum diethylphosphinate is widely used in products such as thermoplastics,thermosetting plastics,fiber and textile as green flame retardant.During the production and the use of ADP,ADP waste water is piped with the characteristics of containing high concentration of organic-phosphorus,which is not only dangerous to the environment,but also difficult to be treated to the emission stander by biological processes.Therefore it is significant to seek fast and effective dephosphorization process for the kind of waste water.In this study,the system of microwave catalytic oxidation was employed to treat aluminum diethylphosphinate of simulated water and practical waste water,in which system Fe₃O₄-CuO@AC as catalyst while hydrogen peroxide and sodium persulfate as oxidant.The effects of different influential factors in the disparate oxidation systems were investigated,including the reaction temperature,the initial pH,the dosage of catalyst and the oxidizing agent.Meanwhile,the best optimum reaction conditions and the remove contribution rate of different ROSs were also determined.Besides,the different degradation rates of ADP in every methods including MW/Fe₃O₄-CuO@ AC,MW/oxidant,waterbath/Fe₃O₄-CuO@AC/oxidant,MW/AC/oxidant,MW/Fe₃O₄-CuO@AC/oxidant were investigated.Furthermore,the effect of Cl^-or HCO3-in the system was explored and the comparison tests of single-oxidation system and double-oxidation system for simulated water and real waste water were also achieved.The main research results include the following:（1）The total phosphorus of 100 ml simulated water was 474.4 mg/L removal reached 40.7% using MW/Fe₃O₄-CuO@AC/H₂O₂ technology under optimal conditions（the reaction temperature was 90 ℃,the initial pH was 6.0,the dosage of catalyst was 2 g,H₂O₂ was 12 mL）,while total phosphorus removal reached 57.6% using MW/Fe₃O₄-CuO@AC/Na₂S₂O₈ technology under optimal conditions（the reaction temperature was 90 ℃,the initial pH was 6.0,the dosage of catalyst was 2 g,Na₂S₂O₈ was 3 g）.（2）Kinetics study indicated that the catalytic oxidation reactions of two single-oxidation systems（MW/Fe₃O₄-CuO@AC/H₂O₂ and MW/Fe₃O₄-CuO@AC/ Na₂S₂O₈）under the best condition both followed the first order kinetics.Radical scavenger test indicated that the contribution ratio of ·OH to degrading ADP waste water was 76.7% while other ROSs ’contribution to the degradation is only 23.3% in MW/Fe₃O₄-CuO@AC/H₂O₂ system.·OH plays a more and more important role while SO4-·played a more and more unimportant role with the increase of pH in MW/Fe₃O₄-CuO@AC/ Na₂S₂O₈ system.（3）Using MW/Fe₃O₄-CuO-AC/oxidant system to degrade ADP had significant higher removal rate than other methods including MW/ Fe₃O₄-CuO@AC,MW/oxidant,water bath/Fe₃O₄-CuO@AC/oxidant and MW/AC/oxidant.The removal of ADP was inhibited in the presence of HCO₃^-both in MW/Fe₃O₄-CuO@AC/H₂O₂ and in MW/Fe₃O₄-CuO@AC /Na₂S₂O₈ system,Cl^-had a strong promoting effect on the dagradation of ADP in MW/Fe₃O₄-CuO@AC/H₂O₂ system,but Cl^-showed a complicated effect in MW/Fe₃O₄-CuO @AC/Na₂S₂O₈ system.The removal efficiency of ADP increased when Cl^-was in low concentration while it was reduced when Cl^-was in high concentration.（4）The results of comparison experiments indicated that the rates of total phosphorus removal in the process of MW/Fe₃O₄-CuO@AC/Na₂S₂O₈+ H₂O₂ were remarkable higher than the single-oxidation system.The removal effects of total phosphorus of simulated water and practical waste water were 85.5% and 71.4% respectively.