Floating metal phthalocyanine@polyacrylonitrile nanofibers for peroxymonosulfate activation: Synergistic photothermal effects and highly efficient flowing wastewater treatment

Utilization of Stable and Efficient High-Entropy (Ni0.2Zn0.2Mg0.2Cu0.2Co0.2)Al2O4 Catalyst with Polyvalent Transition Metals to Boost Peroxymonosulfate Activation toward Pollutant Degradation

A polyacrylamide gel method has been used to synthesize a variety of polyvalent-transition-metal-doped Ni position of high entropy spinel oxides (Ni0.2Zn0.2Mg0.2Cu0.2Co0.2)Al2O4-800 °C (A2) on the basis of NiAl2O4, and the catalytic activity of A2 is studied under the synergistic action of peroxymonosulfate (PMS) activation and simulated sunlight. The A2 containing polyvalent transition metals (Ni2+, Cu2+, and Co2+) can effectively activate PMS and efficiently degrade levofloxacin (LEV) and tetracycline hydrochloride (TCH) under simulated sunlight irradiation. After 90 min of light exposure, the degradation percentages of LEV (50 mg L-1) and TCH (100 mg L-1) degrade by the A2/PMS/vis system reach 87.0% and 90.2%, respectively. The superoxide radicals, photoinduced holes, and singlet oxides dominate the catalytic process, while hydroxyl radicals and sulfate radicals play only a small role. The adsorption energy and charge density difference between different systems and PMS are calculated by density functional theory, and the activation efficiency of PMS is studied by combining with the change of the length of the O─O bond of the PMS after adsorption. The catalytic mechanism of A2/PMS/vis system is proposed, which provides a new idea and method for the study of high entropy oxides in the field of catalysis.

Advancements in iron-based photocatalytic degradation for antibiotics and dyes

The accelerated growth of the economy and advancements in medical technology have led to the discharge of a diverse range of organic pollutants into water sources. Recent investigations into water treatment have demonstrated the potential for integrating photocatalysis with techniques such as photocatalytic persulfate activation and the Photo-Fenton process for more efficient wastewater management. Iron-based photocatalysts responsive to visible light offer several advantages, including non-toxicity, safety, affordability, and excellent chemical and optical properties. Currently, there is a notable increase in research activity focused on the iron-based photocatalytic degradation of antibiotics and dyes. Given their abundance, cost-effectiveness, and eco-friendliness, iron-based photocatalysis shows considerable promise for various applications, including water treatment, air purification, and energy conversion. The use of iron-based photocatalysts has been demonstrated to facilitate the production of more reactive oxygen radicals, achievable through the Photo-Fenton process, direct photocatalysis, and the photocatalytic activation of persulfates. This approach has been demonstrated to enhance the degradation efficiency of antibiotics and dyes. Ongoing research encompasses the preparation and refinement of iron-based materials, exploration of photocatalytic mechanisms, and expansion of practical applications. Future directions include material innovation, elucidation of mechanisms, scaling up applications, and multifunctionalization, with the objective of enhancing photocatalytic efficiency, transitioning the technology from laboratory settings to practical scales, and providing effective solutions to environmental challenges and energy constraints.

Design of multiple anti-fouling and honeycomb-like NH2-AgBiS2 @g-C3N4 hydrogel layer onto PAN fiber membrane for multicomponent pollutant-oil-water emulsion treatment

Nano-structured hydrogel with unique anti-oil fouling property exhibits big advantage in oil/water separation, but its application in complex oily wastewater (contain oils, organic matter, bacteria, etc.) cleanup is hampered by the insufficient capabilities in multi-antifouling and synergistic treatment. Herein, we constructed the amino-rich NH2-AgBiS2/PANI (polyaniline)-g-C3N4 based multi-functional hydrogel functional layer onto the polyacrylonitrile (PAN) fiber membrane via polyphenol-mediated chitosan gelation and vacuum-assisted self-assembly techniques. The unique honeycomb-like structure and super-wetting feature synergistically contributed to the powerful oil resistance and flux breakthrough of composite membrane. Such membrane achieved superior permeability (up to 3558 L-1 m-2 h-1) for various SDS-stabilized oil-in-water emulsions and remarkable synergistic treatment efficiency of multicomponent pollutant-oil-water emulsion. The rational design of hydrogel layer on membrane surface intensified the photo-response ability and multiple electron transport channels, which offered the favorable photocatalytic self-cleaning performance towards degradation of organic dyes. According to the free radical quenching and EPR experiments, the photocatalytic mechanism was proposed. In addition, the inhibition rate of E. coli could reach 100 % under illumination of 24 h. Therefore, the integration of ultra-low oil adhesion, photocatalytic self-cleaning, and antibacterial features endows membrane with exceptional multiple anti-fouling performance, exhibiting unique advantages over traditional membranes in handling complex membrane fouling issues.

Swallowed Embedding of Nanopetal-Rich Microflowers in Flexible Photocatalytic and Thermoresponsive Functional Composite Fibers

Developing efficient catalysts to degrade pollutants in water is a very important way to alleviate water pollution. However, it is crucial but challenging to broaden the functions of conventional photocatalysts and improve their environmental adaptability. In this paper, Bi(Er3+/Yb3+)OBr/polyacrylonitrile (BOB-EY/PAN) composite fibers with a swallowed-embedded structure assembled with nanopetal-rich microflowers were designed and fabricated, integrating photocatalytic and temperature-monitoring functions simultaneously. Their unique structure brings a large specific surface area, and the doping of rare earth ions improves the separation efficiency of electron-hole pairs, which enhances the photocatalytic efficiency and endows the fibers with a temperature-monitoring function at the same time. Under simulated sunlight irradiation, the nanofibers show a maximum degradation efficiency of 99.2% for tetracycline hydrochloride (TC) with a degradation constant of K as high as 0.078 min-1. Based on the fluorescence intensity ratio (FIR), the two thermally coupled levels of Er3+ in the nanofibers, 2H11/2 and 4S3/2, provide real-time temperature feedback, displaying a maximum relative sensitivity as high as 0.0215 K-1 at 303 K. Dual-functional BOB-EY/PAN composite nanofibers show great potential for industrial wastewater disposition, providing solutions for wastewater purification in special scenarios.