Crosslinked biomimetic coating modified stainless-steel-mesh enables completely self-cleaning separation of crude oil/water mixtures

Poly(sulfobetaine) versus poly(ethylene glycol) based copolymer modified polyurethane catheters for antifouling

Polyurethane (PU) catheters are commonly used in clinical treatment. However, the hydrophobic nature of the PU catheter surface leads to adhesion or adsorption to platelets, proteins, bacteria, and other molecules when used in human treatment. To achieve a surface with strong hydrophilicity, high stability and excellent biocompatibility, it is necessary to functionalize the PU catheters. In this paper, a coating with antifouling function was constructed on the surface of PU catheters using plasma technology and an amide coupling reaction. A series of characterization methods, including X-ray photoelectron spectroscopy (XPS), water contact angles (WCA), and atomic force microscopy (AFM), were used to prove the successful modification of the polymer coatings. The coatings showed good stability under conditions such as PBS (pH 7.4, 720 h), 75% ethanol (6 h) and 1 wt% SDS (10 min). Additionally, the coatings exhibit excellent hemocompatibility and antibacterial properties. The PU/PEI/PCSB coating has the best anti-fouling performance among them, which means that using the PCSB copolymer has the potential to modify different clinical catheters into highly effective antifouling coatings.

An efficient solution based on the synergistic effects of nickel foam in NiFe-LDH nanosheets for oil/water separation

Efficient oil-water separation has always been a research hotspot in the field of environmental studies. Employing a one-step hydrothermal approach, NiFe-layered double hydroxides (LDH) nanosheets were synthesized on nickel foam substrates. The resulting NiFe-LDH/NF membrane exhibited rejection rates exceeding 99% across six diverse oil-water mixtures, concurrently demonstrating a remarkable ultra-high flux of 1.4 × 106 L·m-2·h-1. This flux value significantly surpasses those documented in existing literature, maintaining stable performance over 1000 manual filtration cycles. These breakthroughs stem from the synergistic interplay among the three-dimensional channels of the nickel foam, the nanosheets, and the hydration layer. By leveraging the pore size of the foam to enhance the functionality of the hydration layer, the conventional trade-off between permeability and selectivity was transformed into a balanced force relationship between the hydration layer and the oil phase. The operational and failure mechanisms of the hydration layer were examined using the prepared NiFe-LDH/NF membrane, validating the correlation between oil phase viscosity and density with hydration layer rupture. Additionally, an extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was employed to investigate changes in interaction energy, further reinforcing the study's findings. This research contributes novel insights and assistance to the comprehension and application of hydration layers in other membrane studies dedicated to oil-water separation.

Hydrophobic organogel sorbent and its coated porous substrates for efficient oil/water emulsion separation and effective spilled oil remediation

Frequent offshore oil leakage accidents and large quantities of oily-wastewater produced in industry and daily life bring huge challenges to global water purification. The adaptability and stability of organogels as adsorbent materials have shown wide application prospects in the field of oil-water separation. Herein, the organogels displayed stable hydrophobic/lipophilic properties with high absorption ability (1200 wt./wt%), efficient sorption of multiple emulsions (>99.0%), and good reusability. More importantly, the organogels were successfully assembled with 2D/3D substrates to achieve excellent sorption capacity (102.5 g/g) and recycling performance (50 cycles). The gel-carbon black assembled on MS (GCB-MS) sorbent with excellent photothermal conversion performance, and can rapidly heat the surface to 70.4 °C under 1.0 sunlight radiation (1.0 kW/m2) and achieved an ultra-high sorption capacity of about 103 g/g for viscous crude oil. Meanwhile, the GCB-MS was combined with a pump to build continuous oil spill cleaning equipment to achieve a super-fast cleanup rate of 6.83 g/min. The developed hydrophobic organogels had been expanded unprecedentedly to realize the comprehensive treatment of oily-wastewater in complex environments, including layered oils, emulsions, and viscous crude oil spill, which provided an effective path for the comprehensive treatment of oily wastewater in complex environments.

Macromolecular grafting of carboxyl polymers on the surface of non-woven fabrics and their adsorption behavior on metal cations

In order to address the issues of the time-consuming, the low density of functional groups and the instability of mussel-inspired adsorbents, an efficient in situ cross-linked mussel-inspired coating-assisted macromolecular grafting strategy was proposed to prepare a polyacrylic acid (PAA) grafted polypropylene nonwoven (PP-g-PAA) for the efficient removal of heavy metal ions. The mussel-inspired coating was formed by rapid deposition in the presence of oxidizing agents and polyamines, and then thiol-terminated polyacrylic acid (PAA-SH) prepared by thiol-ene click reaction and glutaraldehyde were added in situ, and then PAA brushes were introduced on the surface of the polypropylene nonwoven via the Michael addition Schiff base reaction between the thiol and o-benzoquinone, and the improvement of the stability of the adsorbent was achieved through in situ formation of the three-dimensional cross-linked structure. A high density carboxyl group functionalized adsorbent with a grafting rate up to 38.98% was obtained, which also exhibited unprecedented tolerance to strong acid, alkali and polar organic solvents. Meanwhile, grafting on polyester nonwovens, sponges and PVDF membrane substrates confirmed the versatility of the proposed method. The PP-g-PAA was characterized by SEM, IR and XPS, and the adsorption behaviors of the adsorbent for Pb2+, Cu2+ and Cd2+ were systematically investigated. The results showed that the adsorption capacity of PP-g-PAA was nearly twice as high as that of the mussel-inspired adsorbent. The adsorption mechanism was also well investigated.

Constructing a Hierarchical Hydrophilic Crosslink Network on the Surface of a Polyvinylidene Fluoride Membrane for Efficient Oil/Water Emulsion Separation

Oil/water mixtures from industrial and domestic wastewater adversely affect the environment and human beings. In this context, the development of a facile and improved separation method is crucial. Herein, dopamine was used as a bioadhesive to bind tea polyphenol (TP) onto the surface of a polyvinylidene fluoride (PVDF) membrane to form the first hydrophilic polymer network. Sodium periodate (NaIO₄) is considered an oxidising agent for triggering self-polymerisation and can be used to introduce hydrophilic groups via surface manipulation to form the second hydrophilic network. In contrast to the individual polydopamine (PDA) and TP/NaIO₄ composite coatings for a hydrophobic PVDF microfiltration membrane, a combination of PDA, TP, and NaIO₄ has achieved the most facile treatment process for transforming the hydrophobic membrane into the hydrophilic state. The hierarchical superhydrophilic network structure with a simultaneous underwater superoleophobic membrane exhibited excellent performance in separating various oil-in-water emulsions, with a high water flux (1530 L.m^-2 h^-1.bar) and improved rejection (98%). The water contact angle of the modified membrane was 0° in 1 s. Moreover, the steady polyphenol coating was applied onto the surface, which endowed the membrane with an adequate antifouling and recovery capability and a robust durability against immersion in an acid, alkali, or salt solution. This facile scale-up method depends on in situ plant-inspired chemistry and has remarkable potential for practical applications.