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Artificial lung (AL) membranes are used for blood oxygenation for patients undergoing open-heart surgery or acute lung failures. Current AL technology employs polypropylene and polymethylpentene membranes. Although effective, these membranes suffer from low biocompatibility, leading to undesired blood coagulation and hemolysis over a long term. In this work, we propose a new generation of AL membranes based on amphiphobic fluoropolymers. We employed poly(vinylidene-co-hexafluoropropylene), or PVDF-co-HFP, to fabricate macrovoid-free membranes with an optimal pore size range of 30-50 nm. The phase inversion behavior of PVDF-co-HFP was investigated in detail for structural optimization. To improve the wetting stability of the membranes, the fabricated membranes were coated using Hyflon AD60X, a type of fluoropolymer with an extremely low surface energy. Hyflon-coated materials displayed very low protein adsorption and a high contact angle for both water and blood. In the hydrophobic spectrum, the data showed an inverse relationship between the surface free energy and protein adsorption, suggesting an appropriate direction with respect to biocompatibility for AL research. The blood oxygenation performance was assessed using animal sheep blood, and the fabricated fluoropolymer membranes showed competitive performance to that of commercial polyolefin membranes without any detectable hemolysis. The data also confirmed that the bottleneck in the blood oxygenation performance was not the membrane permeance but rather the rate of mass transfer in the blood phase, highlighting the importance of efficient module design.

Power plants consume a major fraction of water to generate electricity, typically in the range between 30–50% of all fresh water sources. Most of the water from plants are lost with heat through st...

Here, highly robust and tight PBI-based OSN membranes were developed by reinforcing the active layer with an ultrathin polydopamine (pDA) coating followed by the simultaneous co-crosslinking of the pDA-coated PBI membrane. Although the pDA layer thickness was just under 5 nm, the pDA layer can effectively improve the rejection properties of the pristine PBI membrane by reducing the overall pore size and filling the defects at the membrane surface. The chemical and physical changes clearly showed the effect of the ultrathin pDA layer and co-crosslinking on the membrane properties and separation performance. The modified PBI membranes showed the improved rejection property and excellent stability in various organic solvents, even in polar aprotic solvents. The co-crosslinked pDA-coated PBI membranes showed a very high rejection properties to low molecular weight solutes (97.6% for 236 Da styrene dimer and 99.9% for 308 Da PPG) with stable solvent permeance. Moreover, significantly improved solvent permeances were observed without a notable decrease in the rejection performance after the prefiltration of polar aprotic solvents. The results showed the effective separation performance enhancement of OSN membranes by ultrathin pDA coating and the potential applications of solvent purification, reuse and valuable chemical recovery in various fine chemical industries.

A membrane module composed of SAPO-34 hollow fibers was constructed for the enrichment of NF 3 , a strong greenhouse gas with a 100-year global warming potential (GWP) 1 of > 17,000. Growth of the SAPO-34 membrane was investigated on the alumina hollow fibers using in-situ growth and secondary growth methods. Heterogeneous nucleation of SAPO-34 crystal took place on the surface because of hetero-atoms existing on the support, contributing to early development of continuous zeolite film. Zeolite membranes were successfully prepared from both in-situ and secondary growth. The membrane prepared by secondary growth presented N 2 permeance as high as 168.4 GPU with an N 2 /NF 3 gas selectivity of 580.7. A SAPO-34 membrane module was assembled using the hollow fiber membranes produced by secondary growth, but separation performance of the module was reduced to N 2 permeance of 136.4 GPU with an N 2 /NF 3 gas selectivity of 133.7. When used for the enrichment of NF 3 gas, a superior yield (98%) and enrichment ratio (20) were obtained from the module at a stage-cut of 0.95.

To enable the wide application of nanofiltration (NF) membranes to increase the fresh water supply, the development of new membrane materials and preparation techniques are still highly desired. In this work, thin-film composite (TFC) NF membranes were fabricated via interfacial polymerization (IP) using three different kinds of biomonomers with trimesoyl chloride (TMC) on a polysulfone (PSf) substrate. Biomonomers such as dopamine hydrochloride (PDA), norepinephrine (PNE), and tannic acid (TA) are highly hydrophilic and environmentally friendly. Moreover, these materials can not only strongly adhere to substrates but can also form chemically stable cross-linked networks. The influence of these monomers on the formation of the selective layer was systematically investigated. Furthermore, a series of characterization techniques, including attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential measurement, molecular weight cutoff (MWCO), X-ray photoelectron spectroscopy (XPS) and separation performance experiments, were used to study the properties of the TFC NF membranes. Biomonomer-based TFC NF membrane exhibited a higher water permeability of 8.14 L/m2 h bar with a high rejection for divalent ions (Na2SO4) of 93% compared to TFC NF membranes.