Microporous membranes comprising conjugated polymers with rigid backbones enable ultrafast organic-solvent nanofiltration

Abstract

Conventional technology for the purification of organic solvents requires massive energy consumption, and to reduce such expending calls for efficient filtration membranes capable of high retention of large molecular solutes and high permeance for solvents. Herein, we report a surface-initiated polymerization strategy through C-C coupling reactions for preparing conjugated microporous polymer (CMP) membranes. The backbone of the membranes consists of all-rigid conjugated systems and shows high resistance to organic solvents. We show that 42-nm-thick CMP membranes supported on polyacrylonitrile substrates provide excellent retention of solutes and broad-spectrum nanofiltration in both non-polar hexane and polar methanol, the permeance for which reaches 32 and 22 l m h bar, respectively. Both experiments and simulations suggest that the performance of CMP membranes originates from substantially open and interconnected voids formed in the highly rigid networks.

Controlling the Selectivity of Conjugated Microporous Polymer Membrane for Efficient Organic Solvent Nanofiltration

“…To highlight the intrinsic capability toward efficient organic solvent nanofiltration, a comparison between the OSN performance of TTB‐CMP membrane with controllable MWCO and previously reported state‐of‐the‐art polymeric OSN membranes, including sub‐10‐nm polyamide membrane, polyarylate membrane fabricated by contorted monomers, normal CMP membrane, COF membrane, and polyamide/MOF mix matrix membrane is provided (Table S5, Supporting Information). Notably, the solvent permeance of TTB‐CMP and TTB‐CMPO membrane are comparable or even higher than the recently reported amorphous polymer membranes.…”

“…Most recently, our group reported 3D conjugated microporous polymers (CMPs) with all‐rigid backbones for ultrafast OSN. The abundant permanent micropores and high pore interconnectivity originating from 3D all‐rigid skeletons endow the CMP membranes excellent solvent permeability and selectivity . Despite the encouraging improvements achieved on solvent permeability, the selectivity controlling in OSN membrane is rarely reported and thought to be even challenging …”

Membrane Separation in Organic Liquid: Technologies, Achievements, and Opportunities

“…Compared with the traditional polymers, the prepared CMP membranes exhibited excellent gas selectivity, indicating the possibility of synthesizing CMP ultrathin membrane for separation, sensing and catalysis. Inspired by the surface polymerization of 1D polymers, our group recently reported surface polymerization of CMPs on the SiO 2 surface modified by initial reaction sites ( Figure ) . By finely controlling the surface modification and polymerization conditions, defect‐free membranes with square centimeter size were successfully obtained.…”

“…c) Nanofiltration performance testing: rejection behaviors of different CMP membranes versus the molecular weight of various dyes; ultraviolet–visible absorption spectra of PPh‐IX dye in methanol to evaluate the separation performance of the p‐CMP membrane; plot of solvent permeance through different CMP membranes against the solvent viscosity. Reproduced with permission . Copyright 2018, Springer Nature.…”

Endowing g‐C3N4 Membranes with Superior Permeability and Stability by Using Acid Spacers

“…[8] Currently,t he further improvement of permeation while retaining acceptable rejection is still at ough task. [10] g-C 3 N 4 nanosheets comprised of aromatic tri-s-triazine unites connected by tertiary amines provide triangular nanopores for molecule transmission. [9] Searching for porous nanosheets to fabricate 2D laminates may be an alternative way to accomplish higher permeances,b ecause pores can offer additional routes for mass transport.…”