Quinone-based Polymer Materials Preparation And Catalyst Effect On Biological Denitrification

During the last two decades,many researches show that redox mediators can accelerate anaerobic biotransformation of azo dyes,perchlorate,arsenate,Cr(VI),carbon tetrachloride and other contaminants.In some cases,they are necessary factor.But natural redox mediator has a complex structure and the redox properties is clearly influenced by the source and artificial redox mediator can not be actually used in environmental engineering,so the experiments are carried out to prepare polymers with redox properties by chemical methods and explore the feasibility of practical application of the polymer catalytic anaerobic biotechnology.In this study,polymerization anthraquinone was prepared under the catalysis of the organic metal catalyst,gel permeation chromatography measured weight average molecular weight of poly(1,5-dichloroanthraquinone)was 53,400.Poly(1,5-dichloroanthraquinone)was able to greatly enhance microbial denitrification process,the denitrification efficiency was 1.9-fold higher than that of the control and 1.3-fold higher than 1,5-dichloroanthraquinone system in 12h,while the nitrite removal rate of poly(1,8-dichloroanthraquinone)system is lower than the 1,8-dichloro-anthraquinone system.The nitrate removal rate of poly(1,5-dichloroanthraquinone)system was stabilized at about 2 times of the control after 4 cycles of the experiment.Five different structures of quinone-based polymer materials were prepared by Friedel-Crafts reaction.They were used as redox mediators in the nitrate denitrifination process,degradation of nitrate and azo dyes.The experimental results showed that the fastest nitrate degradation was PDMBQ system in 10h,which was 1.48-fold of the control;and the fastest degradation of Acid Red B was PNQ system in 8h,which was 1.53-fold higher of the control.Optimum conditons of the preparation PNQ were vector:naphthoquinone=1:1,temperature 78?.Five copolymers with different structure were prepared to explore the characteristic of accelerating denitrification process.The experimental results showed that the in PDMBQ system pH changed faster and stable at about 9.5.The oxidation-reduction potential(ORP)and nitrite nitrogen was 123 mV and 29.7mg/L,respectively.Accelerating effects of PDMBQ on the nitrate denitrifination process were studied,the results showed that the optimum conditions were temperature 38?,,pH(7),C/N ratio 6,PDMBQ concentraion of 2068.0mg/lL.This experiment explored the conception of efficient biological denitrification and put forword a great improvement of the redox mediator's application in water treatment.This result for the practical appliacation of redox mediators has laid a theoretical and technical basis.