Fine-tuning selective layer architecture of hydrogel membrane towards high separation performances for engineered osmosis

Designing Hydrogel-Modified Cellulose Triacetate Membranes with High Flux and Solute Selectivity for Forward Osmosis

“…These trends correspond to a more hydrophilic surface because of the existence of a smooth layer and the hydrophilic nature of the hydrogel, and the results are in good accordance with these refs ,, Interestingly, the contact angles of hydrogel-modified CTA membranes increase following the order MMA-CTA < EMA-CTA < BMA-CTA. This observation can be explained by the increasing chain length of aliphatic C x H y groups, which typically decreases hydrophilicity and aqueous solubility. − …”

“…As described above, all the hydrogel-modified membranes exhibited a much smoother surface (Figure ) and lower contact angles (Figure ), which are not ideal for bacterial growth. ,,, Confirming this, we observed relatively few bacterial cells on the membranes when they were incubated overnight (Figure S3). Representative images show that single live cells interspersed with some dead cells can be observed on the membrane surfaces.…”

“…These results can be understood in terms of the internal concentration polarization experienced by the solutes (water and draw agent) because of the nonporous active layer (Figure C) for the commercial HTI-CTA membrane. Another landmark study using an ultrathin PVA hydrogel selective layer supported by a GO/PES substrate (depicted in Figure B) also showed similar excellent results, in which a high J w of 27 L m –2 h –1 and low J s / J w ratio of 0.10 were obtained . Although the water flux was comparable with that of our BMA-CTA membrane, the hydrogel layer thickness is 1 order of magnitude smaller than the membrane thickness of BMA-CTA.…”

“…A hydrogel FO system has recently been conceptualized to show the utility of hydrogels as draw agents to not only enhance membrane water fluxes but also to become thermally responsive. − This has attracted increased development in the stimulus responsiveness of hydrogel FO research via electric, , magnetic, , and textural − properties of hydrogels for FO and other niche liquid separation applications. However, these hydrogel functional design strategies were developed to realize the mechanism of water release from the hydrogels via an external energy source for continuous production of fresh water.…”

The Origin of the Non-Constancy of the Bulk Resistance of Ion-Selective Electrode Membranes within the Nernstian Response Range

“…By contrast, membranes’ structural features and non-homogeneity are considered crucial for the membrane performance for separation. Tuning of the architecture of hydrogel membranes was used to improve engineered osmosis [ 33 ]. Boron nitride nanosheets in polyvinylidene fluoride-co-hexafluoropropene membranes were incorporated for improved desalination performance [ 34 ], and aliphatic polyketone membranes were doped with alginate additive to accelerate or inhibit solvent-nonsolvent exchange rate and improve the hydrophilicity of the membranes [ 35 ].…”