Regulation of Polyvinyl Alcohol/Sulfonated Nano-TiO2 Hybrid Membranes Interface Promotes Diffusion Dialysis

It is important to emphasize that the adjustment of an organic&ndash
inorganic interfacial chemical environment plays an important role during the separation performance of composite materials. In this paper, a series of hybrid membranes were prepared by blending polyvinyl alcohol (PVA) solution and sulfonated nano-TiO2 (SNT) suspension. The effects of different interfacial chemical surroundings on ions transfer were explored by regulating the dosage content of SNT. The as-prepared membranes exhibited high thermal and mechanical stability, with initial decomposition temperatures of 220&ndash
253 &deg
C, tensile strengths of 31.5&ndash
53.4 MPa, and elongations at break of 74.5&ndash
146.0%. The membranes possessed moderate water uptake (WR) values of 90.9&ndash
101.7% and acceptable alkali resistances (swelling degrees were 187.2&ndash
206.5% and weight losses were 10.0&ndash
20.8%). The as-prepared membranes were used for the alkali recovery of a NaOH/Na2WO4 system via the diffusion dialysis process successfully. The results showed that the dialysis coefficients of OH&minus
(UOH) were in a range of 0.013&ndash
0.022 m/h, and separate factors (S) were in an acceptable range of 22&ndash
33. Sulfonic groups in the interfacial regions and &ndash
OH in the PVA main chains were both deemed to play corporate roles during the transport of Na+ and OH&minus