Asymmetric PEEKWC membranes for treatment of organic solvent solutions

Hollow Fiber Membrane for Organic Solvent Nanofiltration: A Mini Review

Organic solvents take up 80% of the total chemicals used in pharmaceutical and related industries, while their reuse rate is less than 50%. Traditional solvent treatment methods such as distillation and evaporation have many disadvantages such as high cost, environmental unfriendliness, and difficulty in recovering heat-sensitive, high-value molecules. Organic solvent nanofiltration (OSN) has been a prevalent research topic for the separation and purification of organic solvent systems since the beginning of this century with the benefits of no-phase change, high operational flexibility, low cost, as well as environmental friendliness. Especially, hollow fiber (HF) OSN membranes have gained a lot of attention due to their high packing density and easy scale-up as compared with flat-sheet OSN membranes. This paper critically reviewed the recent research progress in the preparation of HF OSN membranes with high performance, including different materials, preparation methods, and modification treatments. This paper also predicts the future direction of HF OSN membrane development.

Novel β-CD@ZIF-8 Nanoparticles-Doped Poly(m-phenylene isophthalamide) (PMIA) Thin-Film Nanocomposite (TFN) Membrane for Organic Solvent Nanofiltration (OSN)

Organic solvent nanofiltration (OSN) membranes are always troubled by the "trade-off" effect between solvent flux and solute rejection. Hence, a rapid, convenient, and effective way to synthesize novel β-cyclodextrin-enhanced zeolite imidazole framework-8 (β-CD@ZIF-8) nanoparticles was first proposed and the nanoparticles were doped into both selective layer and poly(m-phenylene isophthalamide) support for fabricating thin-film nanocomposite membranes. Transmission/scanning electron microscopy images and X-ray photoelectron spectroscopy results demonstrate the successful synthesis of β-CD@ZIF-8. Atomic force microscopy images illustrate the more rougher surface compared to the pristine membrane, while the pure acetone flux reached 62.3 ± 2.3 L m^-2 h^-1, and Rose Bengal rejection achieved 96.6 ± 1.8 and 94.5 ± 0.5% in methanol (MeOH) and tetrahydrofuran at 0.6 MPa, respectively, when the dosage was 0.05% (w/v). The molecular weight cutoff around 574 Da of PPA2505 containing β-CD@ZIF-8 in both support and selective layers shows the optimum properties and outstanding OSN performances in erythromycin concentration and purification in MeOH and butyl acetate. Additionally, polyimide nanofiber and the formed net structure may offer a potential way to fabricate "ultrathin" film in the OSN industry.

The Selectivity Challenge in Organic Solvent Nanofiltration: Membrane and Process Solutions

Recent development of organic solvent nanofiltration (OSN) materials has been overwhelmingly directed toward tight membranes with ultrahigh permeance. However, emerging research into OSN applications is suggesting that improved separation selectivity is at least as important as further increases in membrane permeance. Membrane solutions are being proposed to improve selectivity, mostly by exploiting solute/solvent/membrane interactions and by fabricating tailored membranes. Because achieving a perfect separation with a single membrane stage is difficult, process engineering solutions, such as membrane cascades, are also being advocated. Here we review these approaches to the selectivity challenge, and to clarify our analysis, we propose a selectivity figure of merit that is based on the permselectivity between the two solutes undergoing separation as well as the ratio of their molecular weights.

ECTFE membranes produced by non-toxic diluents for organic solvent filtration separation

A new grade of ethylene-chlorotrifluoroethylene, low melting point HALAR® ECTFE (LMP ECTFE), was studied and used as a polymer for the preparation of solvent-resistant flat-sheet membranes.

Mixed matrix membranes containing MIL-53(Al) for potential application in organic solvent nanofiltration

PMIA MMMs with various amounts of MIL-53(Al) were developed through non-solvent induced phase separation and the MMMs permeance was increased dramatically while keeping high rejections in organic solvent nanofiltration.