Quinone-based Polymer Materials Preparation And The Application Of Wastewater Biochemical Treatment

With the development of increasing environmental problem,biological treatment method is the preferred technology But the low rate of anaerobic biodegradation was the bottleneck of refractory pollutants biodegradation.Recently the catalytic technology of redox mediator provided a new method for efficient biodegradation of refractory pollutants.The aim of this study is to develop three nonsoluble quinonyl redox mediators,and they are three kinds of functional polymer materials containing quinonyl modified starch,PA membrane,and PVA sponge.Theirs catalytic performance for the azo dye decolorization and nitrates denitrification was also investigated.The best conditions of cross-linked starch synthesis were reaction temperature 45?,reaction time 3h,1:0.2 of the molar ratio of starch and epichlorohydrin,and 1:0.15 of the molar ratio of starch and sodium hydroxide.The settlement of the modified starch and crosslinking degree were moderate under optimum conditions.Infrared spectrum analysis proved that group of quinonyl had successfully grafted on the macromolecule skeleton of starch.Thermo-gravimetric analysis showed that quinonyl changed the molecular structure of the starch and reduced the thermal stability of starch.The fastest catalytic efficiency to the azo dyes decolorization was naphthquinone starch,which enhaced the decolorization efficiency 2.6 times after 4h.Quinonyl starch had obvious the accelerating effect on the microbial denitrification,and the accelerating order was followed by benzoquinone starch,anthraquinone tarch,naphthoquinone starch,and benzoquinone starch had the best denitrification among them,which was up to 82.86%.The preparation of quinonyl PA membrane was divided into two steps:nylon membrane hydrolysis and quinone of grafting.The optimum conditions of nylon membrane hydrolysis were 3mol/L hydrochloric acid,35?,hydrolysis time 72h.The amino content on the surface of the nylon membrane was 122.21mmol/g under the optimum hydrolysis condition.By azo dye decolorization efficiency as evaluation index,the optimum conditions of nylon membrane grafting quinonyl was reaction time 6h and 30?.The element analysis showed that the content of the quinonyl on the surface PA membrane was O.llmmol/g SEM analysis suggested that quinonyl fixed reaction didn't destroy PA membrane surface structure.Quinonyl PA menbrane also accelerated the denitrification efficiency,which was 1.9-fold higher than blank system in 10h.The decoloring rate of quinonyl PA membrane system was 1.2-fold higher than the blank system in 2.5h,and ORP with quinonyl PA membrane in the azo dye decolorization process was reduced.Six repeated experiments of quinoneyl PA membrance showed the denitrificationl efficiency stabilized above 80%,which demonstrated that the quinoneyl PA membrane had a certain stability in the biological treatment.The preparation of quinonyl PVA sponge was divided into two steps:amination reaction and quinonyl fixation.The optimum conditions of PVA sponge amination was reaction time 6h and 30?.the optimum conditions of quinonyl fixation was reaction time 2h and 40 ?;the quinonyl content on the PVA sponge surface was 0.08mmol/g by element analysis.SEM showed that quinonyl group grafted on the PVA sponge surface successfully.The decolorization rate with quinoneyl PVA sponge was 90.2%after 2.5h,which was 1.3-fold higher than the blank system;Quinonly PVA sponge also accelerated thedenitrification efficiency,which was 1.4-fold higher than the blank system in 6h.After 11 repeated experiments,the decolorization rate remained above 90%.and the quinonly PVA sponge had a good repeatability.To sum up,the three kinds of quinone redox mediator materials not only had high catalytic activity to the azo dye decolorization and the denitrification in this study,but also had good catalytic stability and wide application prospects.