Interfacially crosslinked ß-cyclodextrin polymer composite porous membranes for fast removal of organic micropollutants from water by flow-through adsorption.

Persistent organic micropollutants have seriously damaged aquatic ecological equilibrium and affected human health. Conventional adsorbents are limited due to slow adsorption rate. Therefore, it's significant to integrate adsorbent into porous membrane to develop a highly efficient continuous filtration method for water purification. Herein, ß-cyclodextrin polymer (ß-CDP) composite porous membranes were prepared via convenient interfacial cross-linking. The membranes combined the adsorption ability of ß-CDP and the convective mass transport process of filtration membrane to quickly remove contaminants from water by flow-through adsorption. In optimized preparation conditions, the composite membrane exhibited a 100% of removal efficiency towards bisphenol A and a high treating capacity up to 440 mg m-2. The treating capacity kept nearly unchanged in acidic and neutral pH condition, while increased greatly with the addition of salts due to the salting-out effect. Also, the membrane could completely remove pollutants with ultrahigh flux up to 2500 L·m-2 h-1. In addition, the used membranes were fully regenerated by mild ethanol cleaning.

Macroporous membranes doped with micro-mesoporous ß-cyclodextrin polymers for ultrafast removal of organic micropollutants from water.

Herein, we report novel macroporous membranes doped with micro-mesoporous ß-cyclodextrin polymers (ß-CDP), named ß-CDP membranes, for water decontamination by the flow-through process. These membranes combine excellent adsorption behavior of ß-CDP and the advantages of membranes filtration including low energy consumption and easy scale-up. Filtration adsorption results demonstrated that the optimal ß-CDP membrane removed > 99.9% of bisphenol A with ultrahigh water flux (3000 L m-2 h-1) or high concentration (50 mg L-1). The dynamic adsorption capacity of the membrane was close to the static maximum adsorption capacity of membrane, suggesting the effective accessibility of adsorption sites. The outstanding adsorption performance was attributed to the synergistic effect of the fast adsorption of ß-CDP, abundant ß-CDP nanoparticles and large contact area offered by spongy pores. Furthermore, not only single other organic micropollutants but also mixture was completely removed by the ß-CDP membranes. In addition, the membranes were easily regenerated by simple ethanol filtration.

Achieving a Collapsible, Strong, and Highly Thermally Conductive Film Based on Oriented Functionalized Boron Nitride Nanosheets and Cellulose Nanofiber.

Boron nitride nanosheet (BNNS) films receive wide attention in both academia and industry because of their high thermal conductivity (TC) and good electrical insulation capability. However, the brittleness and low strength of the BNNS film largely limit its application. Herein, functionalized BNNSs (f-BNNSs) with a well-maintained in-plane crystalline structure were first prepared utilizing urea in the aqueous solution via ball-milling for the purpose of improving their stability in water and enhancing the interaction with the polymer matrix. Then, a biodegradable and highly thermally conductive film with an orderly oriented structure based on cellulose nanofibers (CNFs) and f-BNNSs was prepared just by simple vacuum-assisted filtration. The modification of the BNNS and the introduction of the CNF result in a better orientation of the f-BNNS, sufficient connection between f-BNNS themselves, and strong interaction between f-BNNS and CNF, which not only make the prepared composite film strong and tough but also possess higher in-plane TC. An increase of 70% in-plane TC, 63.2% tensile strength, and 77.8% elongation could be achieved for CNF/f-BNNS films, compared with that for CNF/BNNS films at the filler content of 70%. Although at such a high f-BNNS content, this composite film can be bended and folded. It is even more interesting to find that the in-plane TC could be greatly enhanced with the decrease of the thickness of the film, and a value of 30.25 W/m K can be achieved at the thickness of ∼30 µm for the film containing 70 wt % f-BNNS. We believe that this highly thermally conductive film with good strength and toughness could have potential applications in next-generation highly powerful and collapsible electronic devices.