Engineering In Situ Catalytic Cleaning Membrane Via Prebiotic-Chemistry-Inspired Mineralization

Construction of Mineralization Nanostructures in Polymers for Mechanical Enhancement and Functionalization

Mineralization capable of growing inorganic nanostructures efficiently, orderly, and spontaneously shows great potential for application in the construction of high-performance organic-inorganic composites. As a thermodynamically spontaneous solid-phase crystallization reaction involving dual organic and inorganic components, mineralization allows for the self-assembly of sophisticated and exclusive nanostructures within a polymer matrix. It results in a diversity of functions such as enhanced strength, toughness, electrical conductivity, selective permeability, and biocompatibility. While there are previous reviews discussing the progress of mineralization reactions, many of them overlook the significant benefits of interfacial regulation and functionalization that come from the incorporation of mineralized structures into polymers. Focusing on different means of assembly of mineralized nanostructures in polymer, the work analyzes their design principles and implementation strategies. Then, their different advantages and disadvantages are analyzed by combining nanostructures with organic substrates as well as involving the basis of different functionalizations. It is anticipated to provide insights and guidance for the future development of mineralized polymer composites and their application designs.

Membranes with Molecular Gatekeepers for Efficient CO2 Capture and H2 Purification

The urgent need for CO2 capture and hydrogen energy has attracted great attention owing to greenhouse gas emissions and global warming problems. Efficient CO2 capture and H2 purification with membrane technology will reduce greenhouse gas emissions and help reach a carbon-neutral society. Here, 4-sulfocalix[4]arene (SC), which has an intrinsic cavity, was embedded into the Matrimid membrane as a molecular gatekeeper for CO2 capture and H2 purification. The interactions between SC and the Matrimid polymer chains immobilize SC molecules into the interchain gaps of the Matrimid membrane, and the strong hydrogen and ionic bondings were able to form homogeneous mixed-matrix membranes. The incorporation of the SC molecular gatekeeper with exceptional molecular-sieving properties improved the gas separation performance of the mixed-matrix membranes. Compared with that of the Matrimid membrane, the CO2 permeability of the Matrimid-SC-3% membrane increased from 16.75 to 119.78 Barrer, the CO2/N2 selectivity increased from 29.39 to 106.95, and the CO2/CH4 selectivity increased from 29.91 to 140.92. Furthermore, when the permeability of H2 was increased to 172.20 Barrer, the H2/N2 and H2/CH4 selectivities reached approximately 153.75 and 202.59, respectively, which are far superior to those of most existing Matrimid-based materials. The mixed-matrix membranes also exhibited excellent long-term operation stability, with separation performance for several important gas pairs still overtaking the Robeson upper limit after aging for 400 days.

Hydrothermal and Laser-Guided Janus Membrane with Dual Wettability for Unidirectional Oil/Water Separation

The development of a Janus membrane with contrasting chemical functionality/or wettability on opposite faces has shown great promise as a passive and energy-efficient oil/water separation technology. Notably, one side of the membrane is designed hydrophilic (i.e., water-attracting in air and underwater oleophobic) and the other hydrophobic (i.e., water-repelling in air and underwater oleophilic). The distinctive surface wettability features of the membrane allow it to repel water and attract oil without consuming energy, thus making it an attractive technology for passively separating oil/water mixtures. The hydrophobic face of the membrane captures oil droplets while allowing water to pass through, and the hydrophilic side attracts water droplets and allows oil to pass. Nonetheless, crafting a Janus membrane is complex, tedious, and expensive. To overcome these limitations, an easy and inexpensive two-step fabrication process for the Janus membrane is proposed in this work. The first step involves creating a superhydrophilic face by the hydrothermally guided deposition of nanoneedles on either side of a commercially available hydrophobic carbon sheet. In the second step, the double-faced surface is subjected to a pulsed laser to create conical micropores studied for oil/water separation. The fabricated membrane is economically affordable and environment friendly. Besides being energy-efficient (as the separation process works passively), the membrane demonstrates an efficient oil/water separating performance. The potential application of this work is diverse and impactful, encompassing wastewater treatment, oil spill cleanup, and various industrial separation processes.