Polyphosphazene membrane for desulfurization: Selecting poly[bis(trifluoroethoxy) phosphazene] for pervaporative removal of thiophene

PEG@ZIF-8/PVDF Nanocomposite Membrane for Efficient Pervaporation Desulfurization via a Layer-by-Layer Technology

The desulfurization property of conventional mixed matrix membranes (MMMs) cannot meet the necessary demand due to particles aggregation and interface defects. Here, we put forward a layer-by-layer (LBL) approach to make a novel PEG@ZIF-8/poly(vinylidene difluoride)(PVDF) composite membrane for pervaporation desulfurization. In this way, a ZIF-8 layer is covered on the surface of the PVDF porous membrane via an in situ growth method. Then, a PEG layer is covered on the ZIF-8 layer by a casting method. Compared with pristine PEG membranes, the separation performance of the ZIF-8@PEG/PVDF nanocomposite membrane increased significantly. This can be attributed to the homogeneous ZIF-8 particle layer and better compatibility between the poly(ethylene glycol) (PEG) matrix and ZIF-8 particles. The membrane achieves a maximum total flux of 3.08 kg·m^-2·h^-1 at the third in situ growth cycles of ZIF-8 particles and a maximum sulfur enrichment factor of 7.6 at the sixth in situ growth cycles of ZIF-8 particles.

Review: Membrane Materials for the Removal of Water from Industrial Solvents by Pervaporation and Vapor Permeation

Organic solvents are widely used in a variety of industrial sectors. Reclaiming and reusing the solvents may be the most economically and environmentally beneficial option for managing spent solvents. Purifying the solvents to meet reuse specifications can be challenging. For hydrophilic solvents, water must be removed prior to reuse, yet many hydrophilic solvents form hard-to-separate azeotropic mixtures with water. Such mixtures make separation processes energy intensive and cause economic challenges. The membrane processes pervaporation (PV) and vapor permeation (VP) can be less energy intensive than distillation-based processes and have proven to be very effective in removing water from azeotropic mixtures. In PV/VP, separation is based on the solution-diffusion interaction between the dense permselective layer of the membrane and the solvent/water mixture. This review provides a state-of-the-science analysis of materials used as the selective layer(s) of PV/VP membranes in removing water from organic solvents. A variety of membrane materials, such as polymeric, inorganic, mixed matrix, and hybrid, have been reported in the literature. A small subset of these are commercially available and highlighted here: poly(vinyl alcohol), polyimides, amorphous perfluoro polymers, NaA zeolites, chabazite zeolites, T-type zeolites, and hybrid silicas. The typical performance characteristics and operating limits of these membranes are discussed. Solvents targeted by the U.S. Environmental Protection Agency for reclamation are emphasized and ten common solvents are chosen for analysis: acetonitrile, 1-butanol, N,N-dimethyl formamide, ethanol, methanol, methyl isobutyl ketone, methyl tert-butyl ether, tetrahydrofuran, acetone, and 2-propanol.

Micro-phase architectural design of fluorinated ethyl cellulose membranes: towards high permeation flux of pervaporation for gasoline desulfurization

A micro-phase architecture of a fluorinated ethyl cellulose membrane was induced by the fluorinated side chains, which disturbs the crystallinity region of EC and highly improves the permeation flux of pervaporation.

Synthesis and characterization of polyurethane/poly(vinylpyridine) composite membranes for desulfurization of gasoline

Polyurethane/poly(vinylpyridine) (PU/PVP) composite membranes for desulfurizing gasoline were prepared.