Application of Bipolar Membrane Electrodialysis in Environmental Protection and Resource Recovery: A Review

Bipolar membrane electrodialysis (BMED) is a new membrane separation technology composed of electrodialysis (ED) through a bipolar membrane (BPM). Under the action of an electric field, H2O can be dissociated to H+ and OH−, and the anions and cations in the solution can be recovered as acids and bases, respectively, without adding chemical reagents, which reduces the application cost and carbon footprint, and leads to simple operation and high efficiency. Its application is becoming more widespread and promising, and it has become a research hotspot. This review mainly introduces the application of BMED to recovering salts in the form of acids and bases, CO2 capture, ammonia nitrogen recovery, and ion removal and recovery from wastewater. Finally, BMED is summarized, and future prospects are discussed

Graphene Oxide Nanosheets Based Novel Facilitated Transport Membranes for Efficient CO2 Capture

A novel fixed carrier composite membrane was prepared via interfacial polymerization by using graphene oxide nanosheets (GO), hyperbranched polyethylenimine (HPEI), and trimesoyl chloride (TMC) coating on a polysulfone membrane. The interfacial polymerization was confirmed with SEM, TEM,. ATR-FTIR, XPS, I)SC; and water contact angle. Further gas separation tests with CO2/N-2 (10:90 v:v) mixed gas confirmed that the addition of GO could significantly improve the CO2 permeance and CO2/N-2 selectivity. The highest CO2 permeance in this work was 9.7 GPU, while the selectivity was over 80. A further gas separation test under different feed gas humidity confirmed the facilitated transport was the main mechanism of gas separation through the membrane, while the addition of GO into the membrane exhibited a synergistic effect with the gas carriers: the surface defects acted as molecule sieves, and the interlayer fixed flow channels ensured a high water content microenvironment to improve the reactivity between CO2 and amino based carriers. Besides, superior stability of the composite membrane was also testified