| Increasingly,more organic and inorganic pollutants are entering the water with the development of industry and agriculture.The complex characteristics of water pollution are becoming more and more prominent:a variety of pollutants coexist,multiple pollution processes occur at the same time.Therefore,the simultaneous removal of many kinds of pollutants is the trend of development and has practical application value.From the point of view of the catalytic mechanism,the hole and electron produced by the light irradiation of TiO2 have strong redox ability respectively.This work was based on the efficient reduction ability of graphene oxide(GO)and F co-doped TiO2(FGT)particles in bromate degradation,the oxidation ability of the removal of ibuprofen or trichloromethane were verified.The batch experiments of photocatalytic oxidation-reduction of bromate and ibuprofen,or bramate and trichloromethane by FGT were further conducted.The performance,mechanism and effect of different factors of synergistic removal of bromate and organics by FGT were discussed.The results shows that FGT has good oxidation efficiency for both organics ibuprofen and trichloromethane.Under the dosage of 0.05 g/L FGT,100 ?g/L ibuprofen with pH of 5.2 could be degraded completely in 10 min.500 ?g/L trichloromethane solution with pH of 6.3 can be degraded 35%in 60 min.At the same time,FGT photocatalysis has a good removal effect on the pollutants in the coexisting systems of bromate and ibuprofen,bromate and trichloromethane,which can play a synergistic role.When pH is 5.2 and the dosage of pH is 0.1 g/L,the reaction rate constants of bromate and ibuprofen increased from 0.0584 min-1?0.4188 min-1 to 0.1353 min-1?0.4504 min-1 respectively compared with the photocatalysis of a single pollutant.Similarly,FGT also played a synergistic role in the removal of bromate and trichloromethane in the coexisting system.When the pH is 6.3 and the dosage of pH is 0.05 g/L,the removal efficiency of bromate was significantly higher than that of the single pollutant.The removal rate of trichloromethane increased from 37%to 41%.At the same time,the investigation of the influencing factors shows that under this experimental condition,the pollutants removal are facilitated by appropriate increase of catalyst dosage,weak acidic solution,low initial concentration and low humic acid concentration.And electrons(e-),hydroxyl radical(·OH)and superoxide radical(·O2-)are the main active species in the photocatalytic synergistic degradation.The e-plays a main role in the bromate reduction,bromine is the only reduction product.While the oxidation of organic is the result of·OH and·O2-,and ·OH plays a key role.It was found that the loss of functional groups,such as carboxyl group,ketone group and side chain substituent group,occurred in the degradation process of ibuprofen in the coexisting system,and there was no sign of ring opening.The mineralization rate of ibuprofen is low,only 30%.The degradaded trichloromethane is oxidized to produce carbon dioxide and HCl,which is completely mineralized.The recombination of electrons and holes is inhibited by simultaneous consumption of bromate and ibuprofen,which makes full use of the redox properties of FGT and plays a synergistic role in the removal of pollutants with a small amount of catalyst.The results indicate that FGT is a promising material for the removal of pollutants in the water treatment due to its remarkable synchronous redox performance.And provides theoretical basis for its practical application in water treatment. |
PDF Full Text Request