Cation-Exchange Membrane with Low Frictional Coefficient and High Limiting Current Density for Energy-Efficient Water Desalination

Abstract

A sulfonated poly(ether ether ketone) (SPEEK) and phosphorylated graphene oxide (PGO) composite of a cation-exchange membrane with low frictional coefficient and high limiting current density has been reported for water desalination by rapid electrodialysis. The incorporation of PGO in the membrane matrix showed a significant impact on the macroscopic properties, counterion frictional coefficient, and performance of the membrane. A well-optimized SPEEK/PGO-8 (8% PGO content, w/w) membrane showed improved conductivity (4.15 × 10 –2 S cm –1 ) and permselectivity (87%), and excellent stabilities (thermal, mechanical, and chemical) because of cherished polymer–PGO (filler) interaction via H-bonding. The efficiency of the SPEEK/PGO-8 membrane was also evaluated for the desalination of brackish water near limiting current density ( I lim ). Ion concentration polarization (ICP) was assessed by i – V curves, and below I lim , water splitting or change in product water pH was ruled out. While above I lim (10.5 mA cm –2 ), ICP was significant and could be finally tuned with applied current density for producing desalinated water with a desired pH. Furthermore, improved I lim , high current efficiency (82.9%), and low energy consumption (7.9 kWh kg –1 of the salt removed) of the SPEEK/PGO-8 membrane during electrodialysis provide a broad current window for efficient and rapid water desalination/purification.

Nanocomposite of Ag nanoparticles and catalytic fluorescent carbon dots for synergistic bactericidal activity through enhanced reactive oxygen species generation

“…This was further supported by the FTIR study (figure S3). A new peak of carboxylic acid group (-COOH) was seen to appear which is possibly due to oxidation reactions during the synthesis of Cdots [33,34]. Zeta potential was carried out to determine the charge of the Cdot and the zeta potential value was obtained as 0.9 mV (figure S4).…”

Combination therapy of biogenic C-dots and lysozyme for enhanced antibacterial and antibiofilm activity

“…In spite of excellent anti-biofilm property, non-biocompatibility, and cytotoxicity of nanomaterials have become the major issue for their clinical usage [16]. Though silver and other inorganic NPs are proven to be a potent antibacterial agent, however, these can induce 'collateral damage' to human cells and symbiotic microbiota [17].…”

Synergistic Effect of 2-Acrylamido-2-methyl-1-propanesulfonic Acid on the Enhanced Conductivity for Fuel Cell at Low Temperature

“…Recently, lots of polymer electrolyte membranes have been prepared from the sulfonation of aromatic polymers such as poly(arylene ether sulfone) [ 1 , 2 , 3 , 4 ] and modified poly(arylene ether sulfone) [ 5 , 6 , 7 ] for the application of electrodialysis and fuel cells as their rigid-rod backbone structures are basically quite stable in thermal and mechanical aspects. To optimize the membrane properties for fuel cell, huge efforts have been additionally given for their chemical and physical modifications such as grafting, [ 8 ] cross-linking, [ 9 ] degree of sulfonation, [ 10 ] surface modification [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ], and composites [ 18 , 19 , 20 , 21 , 22 ].…”

“…Even though those sulfonated aromatic polymers have shown quite promising results [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] some critical shortcomings in membrane properties limited their wide commercialization. The proton conductivity of aromatic polymer membranes is generally lower than that of Nafion, a typical commercial polymer electrolyte membrane, because the aromatic polymer membranes usually form relatively smaller ion cluster dimensions for water flow in association with the lower acidic ion cluster environment.…”