Series-connected hexacations cross-linked anion exchange membranes for diffusion dialysis in acid recovery

Publication date: Available online 18 October 2018Source: Journal of Membrane ScienceAuthor(s): Jun Feng, Jianchao Chen, Biaowen Wei, Shijun Liao, Yigang Yu, Xiuhua LiAbstractA series-connected tetracation cross-linker, DB, was synthesized successfully from 1,4-diazabicyclo[2.2.2]octane (DABCO) and dibromomethane. Which had two terminal tertiary amine groups and reacted with the bromomethylated poly(aromatic ether sulfone) (BPAES) based on 9,9-bis(4-hydroxyphenyl)fluorene and the other copolycondensation monomers giving a series of series-connected hexacations cross-linked anion exchange membranes, QPAES-DBs, for acid recovery by diffusion dialysis (DD). When applied in mostly reported simulated solution mixture of HCl and FeCl2, QPAES-DB50 shows the best DD performances with separation factor of H+ to Fe2+ (SH+/Fe2+) value of 127 and dialysis coefficient of hydrogen ion (UH+) value of 18.92×10−3 m/h, which are much higher than that of the commercial membrane TWDDA1 (UH+ = 9.18×10−3 m/h, SH+/Fe2+ = 38.08). The phenomena are possibly resulted from the strengthened DONNAN effect provided by the crosslinking network containing series-connected hexacation segments at a certain crosslink density. In addition, the application in DD of QPAES-DB50 was extended to the multi-metals ions chlorides system of Mn2+/Ni2+/Cu2+/Cd2+/Cr3+. The separation factors of H+ to Ni2+, Mn2+, Cr3+, Cu2+ and Cd2+ reach up to 137.48, 119.90, 54.59, 32.84 and 16.19 separately. Evidently, QP...
Source: Journal of Membrane Science - Category: Materials Science Source Type: research