Novel Silica Functionalized Monosodium Glutamate/PVA Cross-Linked Membranes for Alkali Recovery by Diffusion Dialysis

Abstract

In this work, two types of silica functionalized monosodium glutamate (GMSG and VMSG)/ poly(vinyl alcohol) (PVA) were cross-linked by sol-gel process to prepare novel hybrid cation exchange membranes (CEMs). The prepared membranes were systematically characterized by FTIR, ion exchange capacity (IEC), TGA, water uptake, water swelling, mechanical strength and diffusion dialysis (DD) performance for alkali separation using NaOH/Na2WO4 solution. The FTIR peaks around 1260-1350 cm −1 confirmed the secondary C−N linkages. The cross-linking between GMSG/VMSG and PVA was verified by the presence of stretching peaks of Si−O−C, Si−O−Si, C−O−C, and −C(=O)−O−C groups between 1080-1120 cm −1 . TGA results indicated that GMSG membranes showed relatively high thermal stability as compared to VMSG membranes. Water uptake and degree of swelling decreased while IEC values increased with the increase of GMSG/VMSG content in membrane matrix. The mechanical properties of the membranes improved up to 40% GMSG/VMSG content. The NaOH dialysis coefficient (UOH)values improved while values of separation factor (S) declined with the increase of GMSG/VMSG content. Finally, the effect of temperature was studied and it was found that increase in temperature from 25 to 45 °C resulted in increase of diffusion coefficient and decrease of separation factor for both GMSG/VMSG crossed-linked with PVA membranes.

Semi-interpenetrating Polymer-Network Anion Exchange Membrane Based on Quaternized Polyepichlorohydrin and Polyvinyl Alcohol for Acid Recovery by Diffusion Dialysis

“…However, when the ratio rose to 50%, membrane E showed slight phase separation and more particle aggregation. The slight phase separation could increase the ion channels and reduce ion transport resistance, and the recovery efficiency of H + ions and Fe 2+ ions increased significantly; these ideas were also confirmed by a subsequent diffusion dialysis experiment …”

“…The slight phase separation could increase the ion channels and reduce ion transport resistance, and the recovery efficiency of H + ions and Fe 2+ ions increased significantly; these ideas were also confirmed by a subsequent diffusion dialysis experiment. 33 3.5. Water Uptake (W R ), Linear Expansion Rate (LER), Ion Exchange Capacity (IEC), and Thickness.…”

“…However, due to the excellent hydrophilicity of PVA, membranes based on PVA with a relatively high W R cannot guarantee the good dimensional stability in the application of an anion exchange membrane. As shown in Table , the W R and linear expansion ratio (LER) values of several AEMs based on PVA are collected, and it can be clearly observed that the W R values can generally reach more than 100%. ,− The high W R led to a high swelling degree and poor dimensional stability, which limited its application in industry. Methods to improve the dimensional stability of membranes have been explored; these methods mainly include cross-linking and blends .…”

Quaternized Diaminobutane/Poly(vinyl alcohol) Cross-Linked Membranes for Acid Recovery via Diffusion Dialysis

“…The characteristics band of the quaternary ammonium [-N + (CH 3 ) 3 ] group is observed at 1469 cm −1 [13,38]. The stretching bands of Si−O−C and Si−O−Si linkages are observed in the region from 1052 to 1150 cm −1 [46,47], while a small peak at 945 cm −1 is attributed to the stretching vibration of the silanol (Si−OH) group [48]. The intensity of the stretching vibration of the -OH band increased with the increase in the QDAB content, as shown in Figure 1.…”

Ionization‐engineered two‐dimensional confined channels in GO membranes for highly efficient OH− separation

“…(B) OH À dialysis coefficients and separation factors of SPPO, GO, PDASA@GO, and SA@GO membranes for alkali recovery. (C) Comparison of alkali recovery performances of PDASA@GO-2 and SA@GO-2 membranes with the GO membrane and existing polymeric cation exchange membranes 7,8,[38][39][40][41][42][43][44][45] (more details in Table S7). The hydration numbers of OH À in the PDASA@GO and SA@GO channels decrease to 6.0 and 5.4, respectively, corresponding to a loss of 0.1 and 0.7 water molecules during channel entry.…”