Preparation And Characterization Of Poly (Arylene Ether)s Anion Exchange Membranes For Acid Recovery By Diffusion Dialysis

Diffusion dialysis（DD）is a process in which solutes in a high-concentration solution migrate to a lower concentration solution through an ion-exchange membrane;this migration is driven by the solute concentration gradients.Therefore,no additional energy or pressure needs to be supplied to a DD process.Compared to the other common methods for the treatment of acidic waste solutions,the DD process with anion exchange membranes（AEMs）has more advantages,including a low consumption of energy,a high efficiency,environmental friendliness,and easy operation.As a crucial component in the DD process for acid recovery,various anion exchange membranes with different structures and effects have been developed by many researchers at home and abroad.In this thesis,two series of poly（arylene ether）s anion exchange membranes were successfully synthesized,and they were applied into diffusion dialysis experiments for acid recovery.The results are as follows:（1）Quaternary ammonium functionalized poly（arylene ether）s（QPAE-Br）membranes based on 2,2’,6,6’-tetramethyl biphenol for diffusion dialysis（DD）were designed and successfully fabricated via nucleophilic substitution polycondensation,bromination,film casting,and quaternization.After the predialysis treatment,those membranes were applied into diffusion dialysis experiment.During the diffusion dialysis test,QPAE-a exhibited an excellent proton diffusion coefficient（U_H⁺）of 0.033 m/h and a high separation factor（S）of95.45 at room temperature;these values were much higher than those of the commercial DF-120B membrane（0.004 m/h for U_H⁺and 24.3 for S at 25 ^oC）and other reported DD membranes.QPAE-a has great potential for acid recovery via DD.（2）The anion exchange membranes containing aryl cationic groups were synthesized via polycondensation,bromomethylation,quaternization.The bromide ion conductivity at 25 ^oC of QBPAES-a,QBPAES-b,QBPAES-c and QBMPAES membrane were 2.22 mS·cm^-1,5.12mS·cm^-1,3.76 mS·cm^-1 and 4.37 mS·cm^-1 respectively.Those membranes were applied into diffusion dialysis experiment for 1.5 h.The proton diffusion coefficient（U_H）of QBPAES-a,QBPAES-b,QBPAES-c and QBMPAES membrane were 0.033 m/h、0.028 m/h、0.023 m/h、0.025 m/h respectively.The separation factor（S）of QBPAES-a,QBPAES-b,QBPAES-c and QBMPAES membrane were 23.45、36.09、17.04、42.48 respectively.