Ultrathin Membranes with a Polymer/Nanofiber Interpenetrated Structure for High-Efficiency Liquid Separations

Abstract

Ultrathin-film composite membranes comprising an ultrathin polymeric active layer have been extensively explored in gas separation applications benefiting from their extraordinary permeation flux for high-throughput separation. However, the practical realization of an ultrathin active layer in liquid separations is still impeded by the trade-off effect between the membrane thickness (permeation flux) and structural stability (separation factor). Herein, we report a general multiple and alternate spin-coating strategy, collaborating with the interface-decoration layer of copper hydroxide nanofibers (CHNs), to obtain ultrathin and robust polymer-based membranes for high-performance liquid separations. The structural stability arises from the poly(dimethylsiloxane) (PDMS)/CHN interpenetrated structure, which confers the synergistic effect between PDMS and CHNs to concurrently resist PDMS swelling and avoid CHNs from collapsing, while the ultrathin thickness is enabled by the sub-10 nm pore size of the CHN layer, the rapid cross-linking reaction during spin-coating, and the small thickness of the CHN layer. As a result, the as-prepared membrane possesses an exceptional butanol/water separation performance with a flux of 6.18 kg/(m 2 h) and a separation factor of 31, far exceeding the state-of-the-art polymer membranes. The strategy delineated in this work provides a straightforward method for the design of ultrathin and structurally stable polymer membranes, holding great potential for the practical application of high-efficiency separations.

Pore engineering of ultrathin covalent organic framework membranes for organic solvent nanofiltration and molecular sieving

“…31 The TFP-DHF membrane showed a remarkably high solvent ux in the application of organic solvent nanoltration. The performance was much better not only than those of conventional OSN membranes built on exible amorphous polymers, [32][33][34][35][36][37][38] but also than those of membranes built on rigid microporous polymers. 39 However, to meet the growing demands for precise molecular sieving it is also critical to rationally tune the pore size.…”

High‐Affinity Adsorbent with Honeycomb Structure for Efficient Acteoside Separation

“…Then supernatant (1 mL) was extracted from sample and through a 0.22 μm filter for testing by HPLC at 330 nm. The selectivity factor (SF) was calculated by Equation (10) to evaluate the selectivity of CMC/PEI-70000-4.5g for ACT.…”

“…At present, the existing separation methods have adsorption method, [6][7][8] membrane separation method, [9,10] and chromatographic separation method. [11] Among them, adsorption method is widely used for adsorption and separation of bioactive components from natural production because of its high efficiency, reusable, lowenergy consumption etc.…”

Simultaneous Increase of Solvent Flux and Rejection of Thin-Film Composite Membranes by Incorporation of Dopamine-Modified Mesoporous Silica

“…Polymer-based thin-film composite membranes have long been the major candidates for practical membrane separation because of the reliability of production and transportation of large-area membranes. − The bottleneck of polymeric membranes is the so-called “trade-off” between permeability and selectivity, which is typically observed for gas separation, pervaporation, desalination, and organic solvent nanofiltration. − In particular, for liquid separation, the solvent-induced membrane swelling usually results in enhanced permeation flux and decreased selectivity or rejection. − Considering that excessive swelling would increase the concerns on membrane stability, the acquisition of high flux at high degree of membrane swelling is not reasonable. Boosting the solvent permeance of polymeric membranes by swelling-independent mechanisms is necessary to overcome the trade-off hurdle for liquid separation. − …”