Synthesis of Porous BPPO-Based Anion Exchange Membranes for Acid Recovery via Diffusion Dialysis

Abstract

Diffusion dialysis (DD) is an anion exchange membrane-based functional separation process used for acid recovery. TMA (trimethylamine) and BPPO (brominated poly (2,6-dimethyl-1,4-phenylene oxide) were utilized in this manuscript to formulate AEMs (anion exchange membranes) for DD (diffusion dialysis) using the phase-inversion technique. FTIR (Fourier transfer infrared) analysis, proton NMR spectroscopy, morphology, IEC (ion exchange capacity), LER (linear expansion ratio), CR (fixed group concentration), WR (water uptake/adsorption), water contact angle, chemical, and thermal stability, were all used to evaluate the prepared membranes. The effect of TMA content within the membrane matrix on acid recovery was also briefly discussed. It was reported that porous AEMs have a WR of 149.6% to 233.8%, IEC (ion exchange capacity) of 0.71 to 1.43 mmol/g, CR (fixed group concentration) that ranged from 0.0046 mol/L to 0.0056 mol/L, LER of 3.88% to 9.23%, and a water contact angle of 33.10° to 78.58°. The UH (acid dialysis coefficients) for designed porous membranes were found to be 0.0043 to 0.012 m/h, with separation factors (S) ranging from 13.14 to 32.87 at the temperature of 25 °C. These observations are comparable to those found in the DF-120B commercial membrane with UH of 0.004 m/h and S of 24.3 m/h at the same temperature (25 °C). This porous membranes proposed in this paper are excellent choices for acid recovery through the diffusion dialysis process.

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

“…This made the increase rate of U Fe 2+ faster than that of U H + , which resulted in the decrease of the S value. Compared with the commercial DF-120 membrane (18.00) and the previously reported membrane (18.5−21, 15 20.90− 32.30, 26 and 15.90−21.00 30 ), the S value of the prepared membranes was higher. The above results suggested that the prepared sIPN membranes had a significant benefit in acid recovery via diffusion dialysis.…”

“…According to its charge, the ion exchange membrane is classified as an anion exchange membrane (AEM) or cation exchange membrane (CEM). , Herein, the research focused on AEMs for acid recovery by DD. The AEM consists mainly of a polymer backbone and ion exchange functional groups. , The polymer backbone of the AEM can be divided into two categories: hydrophobic and hydrophilic. , Hydrophobic polymers mainly include poly­(arylene ether sulfone)­s (PAESs), poly­(vinylidene fluoride) (PVDF), poly­(2,6-dimethyl-1,4-phenylene oxide) (PPO), − poly epichlorohydrin (PECH), poly­(ether ether ketone) (PEEK), and polysufone (PSF) …”

Internally Cross-Linked Polysulfone-Based Anion Exchange Membranes with pH Stability for Carboxylate Separation

“…The spectra reveal peaks at 1580 and 1484 cm –1 , which correspond to the benzene ring in the CMPSF. , Additional bands, such as those at 1297, 1146 cm –1 , point to symmetric stretching vibrations of the OSO group . The peak at 690 cm –1 was assigned to vibrations of the C–Cl. , Notably, when compared with QPSF-0 AEMs, a new peak at 1634 cm –1 emerges in QPSF- n AEMs, which indicates the presence of either an amide group or a quaternary ammonium group.…”

Auxiliary functional group diffusion dialysis membranes for acid recovery

“…Figure 8 indicates that hydroxyl plays an auxiliary role during the transporting process of H + through the membrane 47 in the following two aspects: (1) in the process of membrane formation, hydroxyl interacts to form a water channel, which is conducive to the passage of hydrated hydrogen ions (H 3 O + ), (2) the oxygen in hydroxyl (–OH) in the membrane is electronegative and can capture protons to form –OH 2 + ions. When the H + concentration is high (material room), hydroxyl (–OH) 24 is easy to combine with H + to form –OH 2 + .…”

“…mainly results from the increasing number of auxiliary groups containing hydroxyl, which leads to the increase of W R of the membrane, and the larger steric hindrance of auxiliary groups enhance phase separation of membrane 46 where the easier transportation of H + ions promotes the DD coefficient of acid (U H + ) of the membrane. Figure 8 indicates that hydroxyl plays an auxiliary role during the transporting process of H + through the membrane 47 in the following two aspects: (1) in the process of membrane formation, hydroxyl interacts to form a water channel, which is conducive to the passage of hydrated hydrogen ions (H 3 O + ), (2) the oxygen in hydroxyl (-OH) in the membrane is electronegative and can capture protons to form -OH 2 + ions. When the H + concentration is high (material room), hydroxyl (-OH) 24 is easy to combine with H + to form -OH 2 + .…”