Synthesis And Functionalization Of Acrylic Acid-hydroxyethyl Methacrylate Copolymer

In this work,the copolymer of acrylic acid(AA)and hydroxyethyl methacrylate(HEMA)was synthesized by using AA and HEMA as monomers and benzoyl peroxide as initiator via precipitation polymerization.The corresponding fiber was prepared by using the aqueous solution of sodium hydroxide as solvent and dilute aqueous solution of sulfuric acid as coagulation medium through wet spinning.Fibrous Fenton catalyst was prepared by using the fiber as a carrier and Fe3+ as an active component via simple impregnation method.It was found that the higher the content of AA in fiber was,the stronger its ability to load iron ions was.The effect of impregnation concentration,temperature and time on the properties of the catalyst was studied,and the related results showed that the catalyst prepared at the conditions including 3:7 of mass ratio of FeCl3·6H2O to H2O in FeCl3 solution,20? of impregnation temperature and 1h of impregnation time exhibited the best performance.10mL of methylene blue(MB)aqueous solution with a concentration of 20mg/L was used as a model pollutant,after 2?L of H2O2 was added in the solution and the solution was bubbled with O3 for 1min,more than 97%of MB could be removed from its solution within 1min under the catalysis of the catalyst.The corresponding fibrous Fenton catalysts were prepared by using Fe3+ and Fe2+as active components at the optimal conditions such as impregnation concentration,impregnation temperature and impregnation time.The morphology,thermal property and reusability of the catalysts were investigated,and the results showed that the performance of the catalysts prepared with different valence iron ions was very different.The fiber only loaded Fe3+ on its surface while the load of Fe2+ took place in both surface and inside.Due to surface load,the fibrous catalyst obtained with Fe3+ as active component exhibited thermal stability similar to the one of its corresponding fiber.Because of surface and inside load,the fibrous catalyst obtained with Fe3+ as active component had better thermal property than its corresponding fiber,and exhibited better reusability in comparison with the catalyst obtained with Fe3+ as active component.Therefore,Fe2+ was selected as the active ingredient for the following research.In order to make the fiber load more iron ions within a short period of time,a loose and porous structure was imparted to the fiber by adopting special processes such as water swelling,freeze drying and alkali lye swelling.The results showed that the catalyst prepared by immersing the loose and porous fiber in FeCl2 solution for 5min had catalytic activity same to the one of the catalyst prepared by immersing the dense fiber in FeCl2 solution for 1h.The effects of alkali concentration,alkali temperature and swelling time on the reusability of the catalyst was researched,and the results showed that the catalyst prepared at the conditions such as 0.1%of NaOH mass concentration,20? of alkali lye temperature and 1h of swelling time could be reused six times,and when it was used for the sixth time MB removal efficiency still reached 95%within 20 minutes.In order to reduce the leaching amount of iron ions during application,the catalyst was thermally crosslinked.During thermal treatment,its carboxyl groups were esterified with its hydroxyl groups or the hydroxyl groups of crosslinking agent,which endowed the catalyst with a crosslinking network structure.The crosslinking network structure could reduce the leaching of iron ions,thus its reusability was improved.The catalyst was prepared by immersing the loose and porous fiber in the solution of FeCl2,4H2O,1,4-butanediol(BDO)and H2O for 1h and performing subsequent crosslinking at different temperature for different time.The effect of impregnation solution composition,thermal crosslinking temperature and thermal crosslinking time on the reusability of the catalyst was investigated,and the results showed that the catalyst prepared at the conditions including 3:1.55:8.45 of mass ratio of FeCl2·4H2O,BDO and H2O,200? of thermal crosslinking temperature and 30min of thermal crosslinking time exhibited good reusability.When it was used for the tenth time,88%of MB removal efficiency could be achieved within 90 minutes.