By combining steric hindrance and electrostatic repulsion, a functionalized Nafion–PEO–graphene (NPG) composite membrane was constructed and used to suppress the shuttle effect of the I−/I3− redox couple.

Sugarcane molasses, which is a kind of microbial carbon source, is a viscous by-product of the refining of sugarcane into sugar. However, experiments were designed to ascertain the mechanism and kinetics of Cr(VI) reduction with sugarcane molasses without adding microbes in aqueous solution. Results indicated that sugarcane molasses can reduce Cr(VI) to Cr(III) at pH values that range from 2.0 to 6.1 when no bioreduction occurs in the reaction. Furthermore, the reaction mechanism was proven to be that Cr(VI) acts as an electrophile that readily accepts electrons from the phenolic hydroxyl group of plant polyphenol, and it is then reduced to Cr(III) and in the process oxidizes the phenolic hydroxyl group to a quinone. Meanwhile, the reaction could be described by the pseudo-first-order kinetic model with respect to Cr(VI) concentration. The reaction rate constants were 324.2, 65.9, 21.9, and 14.4 h −1 when pH values were 2.0, 3.5, 5.0, and 6.1, respectively, at 20°C. The k obs increased 3.36, 7.02, and 13.48 times with the temperature adjusted from 5 to 10, 20, and 30°C.

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The remediation of Cr(VI) is one of the hot issues in groundwater pollution remediation. The influences and effects of pH on Cr(VI) reduction by organic reducing substances in sugarcane molasses were studied under the sterilization and unsterilization conditions by means of batch laboratory-scale experiments. The results showed that pH of reaction solution has a great influence on the reduction of Cr(VI) by sugarcane molasses. When pH ≥ 3.0, the final removal efficiency of Cr(VI) on the condition of sterilization and unsterilization at pH values of 8.0, 5.8, 4.0 and 3.0 was 15.441%, 17.945%, 29.205%, 36.258% and 99.236%, and 98.577%, 99.235% and 99.368%, respectively. When pH < 3.0, the final removal efficiency of Cr(VI) on the condition of sterilization and unsterilization at pH values of 2.5 and 2.0 was 99.631% and 99.895%, and 99.631% and 99.895%, respectively. The main mechanism involves chemical reduction and biological reduction. And biological reduction in the process of Cr(VI) reduction by sugarcane molasses is of the first priority when pH ≥ 3.0; when pH < 3.0, the rate of chemical reduction was higher and it was not the basic existing biological reduction. The relationship between pH and pseudo-first-order rate constant (k obs) on both the sterilization and unsterilization conditions was satisfied with Boltzmann model. There is an inflection point at the pH of about 2.6, which also indicated the influence mechanism of pH on the reduction of Cr(VI) by sugarcane molasses.

A freestanding ion membrane with high ionic conductivity, electrochemical compatibility, satisfactory strength, and safety is a goal pursued for advanced energy storage. Geminal dicationic ionic liquids (GDILs) are expected to be designed and synthesized as a basic building block for the target ionic conductors. Herein, we fabricated a GDIL-based flexible ion conductive material, which appears and behaves as a freestanding film, an ion membrane actually, denoted as iMembrane. The iMembrane presented high thermal stability, broad electrochemical stability, and capable ionic conductivity. Stable lithium-ion intercalation/de-intercalation can be achieved at the iMembrane/graphite interface without co-intercalation of imidazole rings, which is attributed to the specific anion-derived solid electrolyte interphase. Moreover, iMembrane is well compatible with the lithium metal anode and LiFePO4 cathode. The soft-packed batteries assembled with iMembrane were punctured with a nail without any fire or smoke. Hence, as an ionic membrane in nonprotonic, iMembrane is promising to enhance safety and energy density of lithium batteries.