Fabrication of porous polymer membrane from polysulfone grafted with acid ionic liquid and the catalytic property for inulin hydrolysis

Catalytic Membrane Nanoreactor with Cu-Agx Bimetallic Nanoparticles Immobilized in Membrane Pores for Enhanced Catalytic Performance

A catalytic membrane nanoreactor (CMNR) with Cu-Ag_x (where x is the millimolar concentration of AgNO₃) bimetallic catalysts immobilized in membrane pores has been fabricated via coupling flowing synthesis and replacement reaction. Surface characterization by transmission electron microscopy (TEM) gives obvious evidence of the formation of Cu-Ag bimetallic core-shell nanostructures with Ag islands deposited on the Cu core metal. An apparent high shift phenomenon for the Cu element and a low shift phenomenon for the Ag element was determined by X-ray photoelectron spectroscopy (XPS), indicating a close interaction with the transfer of electron density from the Cu atom to the Ag atom. The hydrogenation catalysis of p-nitrophenol (p-NP) was tested to evaluate the catalytic performance. During the catalytic process, the Cu core acts as an electron-deficient site to adsorb and activate the -NO₂ group for p-NP, and the Ag shell is beneficial for enhancing active H spilling to the Cu surface and then performing hydrogenation. A volcano-shaped apparent reaction rate constant can be achieved, which rises initially with the increasing Ag content and subsequently drops with a further increase in the Ag content. The highest value of 1071 min^-1 can be achieved for CMNR immobilized with Cu-Ag₂ owing to the suitable adsorption activation behavior and the best hydrogen spillover behavior.

Improving Sustainability of the Griess Reaction by Reagent Stabilization on PDMS Membranes and ZnNPs as Reductor of Nitrates: Application to Different Water Samples

A new approach based on the use of polydimethylsiloxane (PDMS) membranes doped with Griess reagents for in situ determination of NO2− and NO3−^- in real samples is proposed. The influence of some doping compounds, on the properties of the PDMS membranes, such as tetraethyl orthosilicate (TEOS), or/and ionic liquids (OMIM PF₆) has been studied. Membrane characterization was performed. To apply the procedure to NO3− determination, dispersed Zn nanoparticles (ZnNPs) were employed. The analytical responses were the absorbance or the RGB components from digital images. Good precision (RSD < 8%) and detection limit of 0.01 and 0.5 mgL⁻¹ for NO2− and NO3−, respectively, were achieved. The approach was satisfactory when applied to the determination of NO2− and NO3− in drinking waters, irrigation and river waters, and waters from canned and fresh vegetables. The results obtained were statistically comparable with those by using nitrate ISE or UV measurement. This approach was transferred satisfactory to 96 wells for multianalysis. This study enables the improvement in the on-site determination of NO2− and NO3− in several matrices. It is a sustainable alternative over the reagent derivatizations in solution and presents several advantages such as being versatile, simplicity, low analysis time, cost, and energy efficiency. The response can be detected visually or by portable instruments such as smartphone.

Ultralight and Mechanically Robust Fibrous Sponges Tailored by Semi-Interpenetrating Polymer Networks for Warmth Retention

People living in very cold climates urgently desire warmth retention equipment to remain healthy. However, creating materials that exhibit both effective warm retention and robust mechanical properties to maintain stable structures is extremely challenging. Herein, we report a facile and time-saving strategy for preparing ultralight, mechanically robust, and high-performance warmth retention materials via direct electrospinning and thermal crosslinking. Fluffy fibrous assemblies with stereoscopic fiber networks are fabricated with a humidity-induced electrospinning technique, followed by heating to create semi-interpenetrating polymer networks (semi-IPNs) within fibers to acquire fibrous sponges (FSs). The semi-IPN-based FSs (semi-IPN FSs) present integrated properties of high tensile stress (∼1 MPa), good fatigue resistance (∼0% plastic deformation after 1000 cyclic tensile or compressive tests), and nondestructive resilience in liquid nitrogen (-196 °C). Furthermore, the semi-IPN FSs exhibit a low volume density of ∼2.2 mg cm^-3, effective heat preservation ability (low thermal conductivity ∼25.8 mW m^-1 K^-1), and desired waterproofness and breathability. The successful synthesis of semi-IPN FSs provides a novel attempt to develop high-performance materials with robust mechanical properties for numerous applications.