Anhydrous proton exchange membranes at elevated temperatures: effect of protic ionic liquids and crosslinker on proton conductivity

Abstract

A series of novel anhydrous proton exchange membranes (poly(vinyl alcohol)-citric acid-ionic liquid (PVA-CA-IL)) were prepared using the low cost ionic liquids ethylammonium nitrate (EAN), diethylammonium nitrate (DEAN), and triethylammonium nitrate (TEAN) as conductive fillers in PVA support membrane. The properties of the PVA-CA-IL membranes can be controlled by changing the molar ratio of the PVA, ILs and CA. The thermal stability of PVA-CA-IL membrane was measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and the microstructure was investigated using scanning electron microscopy (SEM) and the Anton-paar SAX Sess mc2 system (SAXS). The effects of temperature, ILs and crosslinker dosage on proton conductivity were also systematically investigated.The results showed that the PVA-CA-IL membranes had excellent performance. The proton conductivity of PVA-CA-EAN (mole ratio ¼ 1 : 0.05 : 0.4) could reach up to 7.8 mS cm À1 at 140 C. The introduction of ionic liquid into PVA membrane constituted a new and efficient kind of anhydrous proton exchange membrane.

Solvent-assisted synthesis of potassium copper hexacyanoferrate embedded 3D-interconnected porous hydrogel for highly selective and rapid cesium ion removal

“…In both cases, the calculated values are slightly smaller than the observed particle size in the TEM analysis ( Fig is attributed to lattice water [37]. In the case of the PC and HPC, the strong absorbance at around 1719 and 1208 cm -1 indicates the stretching vibrations of C=O and C-O-C relating to the esterification reaction between -OH in poly(vinyl alcohol) and -COOH in citric acid [26,38]. A broad and strong band covering the range 3000-3700 cm -1 relates to the symmetrical stretching vibration from inter and intramolecular hydrogen bonds of O-H [39].…”

“…For this purpose, poly(vinyl alcohol) (PVA) and citric acid were utilized as the polymer backbone and crosslinking agent due to their low cost, nontoxicity, and hydrophilic properties [25,26]. In addition, the components have abundant oxygen functionalities such as hydroxyl or carboxyl groups which can coordinate metal ions for anchoring and distribution of KCuHCF particles [23,26]. The HPC was synthesized using a two-step procedure ( Fig.…”

Highly effective Cs+ removal by turbidity-free potassium copper hexacyanoferrate-immobilized magnetic hydrogels

“…6), initial weight loss up to 220 °C was associated to the evaporation of adsorbed water. The rapid weight loss in the temperature range of 220 to 500 °C was ascribed to the degradation of PVA backbone and removal of oxygen functional groups [41]. Beyond 330°C, the gradual weight loss for the HPVA and MHPVA was due to the decomposition of both the PVA hydrogel and hydrogen cyanide from the KCuHCF structure [31,42].…”

Proton conducting electrolytes composed of chondroitin sulfate polysaccharide and citric acid

“…DESs) with other organic entities, namely choline, various sugars or proline [30,45]. Also of note is the increasing use of CA as a plasticizer [46,47] and a cross-linker [44,46], including in the preparation of proton exchange membranes [47]. A similar strategy was employed in the preparation of SPEs composed of chitosan and carboxylic acids, such as oxalic acid [48,49], acetic acid [50] or maleic acid [16].…”