Superhydrophilic PVDF Membrane Modified by Norepinephrine/Acrylic Acid via Self-Assembly for Efficient Separation of an Oil-in-Water Emulsion

Fabrication of norepinephrine and ε-polylysine engineered magnetic nanocomposites tailored for phosphopeptides analysis

Protein phosphorylation is a highly prevalent post-translational modification that holds a vital position in numerous physiological processes. Prior to mass spectrometry detection, the enrichment of phosphopeptides is critically significant due to their susceptibility to interference from abundant non-phosphopeptides. In this study, the magnetic nanocomposite (Fe3O4@NE@PL) was successfully synthesized and characterized. Fe3O4@NE@PL exhibited strong hydrophilicity, electrophilicity and intermolecular interactions through hydrogen bonds, enabling it to effectively enrich phosphopeptides with excellent sensitivity (0.4 fmol β-casein) and selectivity (β-casein:BSA=1:1000). In addition, Fe3O4@NE@PL was successfully applied to enrich phosphopeptides from complex real biological samples such as human serum and saliva, achieving up to 4 recycles with favorable stability and reusability. This study demonstrates that Fe3O4@NE@PL is a promising adsorbent for phosphopeptides enrichment in proteomics research, providing new ideas for the construction of magnetic enrichment materials.

Rapid Construction of Caffeic Acid/p-Phenylenediamine Antifouling Hydrophilic Coating on a PVDF Membrane for Emulsion Separation

The current methods of constructing modification strategies for hydrophilic membranes are time-consuming, complex in operation, and poor in universality, which limit their application on membranes. In this work, inspired by the adhesion properties and versatility of caffeic acid (CA) and p-phenylenediamine (PPDA), a simple, rapid, and universal method was designed for the separation of oil-in-water emulsion by preparing a stable hydrophilic coating separation membrane. The preparation time of the membrane was shortened to 40 min. The developed PVDF-PCA/PPDA membrane showed superhydrophilic and underwater superoleophobic properties. When applied to petroleum ether-in-water emulsion, isooctane-in-water emulsion, and dodecane-in-water emulsion separation, the oil rejection was more than 99.0%. In the circulating separation of 10 g/L soybean oil-in-water emulsion, the oil rejection was more than 99.3%, and the highest flux was 1036 L·m-2·h-1. The prepared PVDF-PCA/PPDA membrane performed well in the separation test of oily wastewater. The proposed strategy is simple and rapid; it may become a universal method for preparing membranes with super strong antifouling properties against viscous oil and accelerate the research progress of membrane separation of oil-in-water emulsions.

Electropositive Membrane Prepared via a Simple Dipping Process: Exploiting Electrostatic Attraction Using Electrospun SiO2/PVDF Membranes with Electronegative SiO2 Shell

This research aimed to develop a simple and cost-effective method for fabricating electropositive membranes for highly efficient water filtration. Electropositive membranes are novel functional membranes with electropositive properties and can filter electronegative viruses and bacteria using electrostatic attraction. Because electropositive membranes do not rely on physical filtration, they exhibit high flux characteristics compared with conventional membranes. This study presents a simple dipping process for fabricating boehmite/SiO₂/PVDF electropositive membranes by modifying an electrospun SiO₂/PVDF host membrane using electropositive boehmite nanoparticles (NPs). The surface modification enhanced the filtration performance of the membrane, as revealed by electronegatively charged polystyrene (PS) NPs as a bacteria model. The boehmite/SiO₂/PVDF electropositive membrane, with an average pore size of 0.30 μm, could successfully filter out 0.20 μm PS particles. The rejection rate was comparable to that of Millipore GSWP, a commercial filter with a pore size of 0.22 μm, which can filter out 0.20 μm particles via physical sieving. In addition, the water flux of the boehmite/SiO₂/PVDF electropositive membrane was twice that of Millipore GSWP, demonstrating the potential of the electropositive membrane in water purification and disinfection.