Photocatalytic removal of Rhodamine B in water using g-C3N4/MIL-53(Fe) material under LED visible light with persulfate activation

Review on magnetic adsorbents for removal of elemental mercury from coal combustion flue gas

Under the influence of human activities, atmospheric mercury (Hg) concentrations have increased by 450% compared with natural levels. In the context of the Minamata Convention on Mercury, which came into effect in August 2017, it is imperative to strengthen Hg emission controls. Existing Air Pollution Control Devices (APCDs) combined with collaborative control technology can effectively remove Hg2+ and Hgp; however, Hg0 removal is substandard. Compared with the catalytic oxidation method, Hg0 removal through adsorbent injection carries the risk of secondary release and is uneconomical. Magnetic adsorbents exhibit excellent recycling and Hg0 recovery performance and have recently attracted the attention of researchers. This review summarizes the existing magnetic materials for Hg0 adsorption and discusses the removal performances and mechanisms of iron, carbon, mineral-based, and magnetosphere materials. The effects of temperature and different flue gas components, including O2, NO, SO2, H2O, and HCl, on the adsorption performance of Hg0 are also summarized. Finally, different regeneration methods are discussed in detail. Although the research and development of magnetic adsorbents has progressed, significant challenges remain regarding their application. This review provides theoretical guidance for the improvement of existing and development of new magnetic adsorbents.

Ternary heterogeneous Z-scheme photocatalyst TiO2/CuInS2/OCN incorporated with carbon quantum dots (CQDs) for enhanced photocatalytic degradation efficiency of reactive yellow 145 dye in water

This study delves into the advanced integration of a ternary heterogeneous Z-scheme photocatalyst, TiO2/CuInS2/OCN (OCN: O-g-C3N4), with carbon quantum dot (CQD) to improve the degradation efficiency of reactive yellow 145 (RY145) dye in water. Through a systematic examination, we elucidated the photocatalytic mechanisms and the role of radicals, electrons, and holes in the treatment process. Our findings revealed that this novel catalyst integration significantly boosted RY145 degradation efficiency, achieving 98.2%, which is markedly higher than the efficiencies which could be achieved using TiO2/CuInS2/OCN alone. Moreover, the TiO2/CuInS2/OCN/CQD photocatalyst demonstrated superior rate performance over its components. Comprehensive evaluations, including photoelectrochemical and radical tests, further confirmed the efficiency of the integrated system, adhering to Z-scheme principles. The catalyst showcased remarkable stability, with over 94% reusability after five reaction cycles. These findings pave the way for the potential use of the TiO2/CuInS2/OCN/CQD photocatalyst as an innovative solution for water pollutant treatment via photocatalytic technology.

Molecular Dynamics and Multi-Spectroscopic of the Interaction Behavior between Bladder Cancer Cells and Calf Thymus DNA with Rebeccamycin: Apoptosis through the Down Regulation of PI3K/AKT Signaling Pathway

The interaction of Rebeccamycin with calf thymus (ctDNA) in the absence and presence of H1 was investigated by molecular dynamics, multi-spectroscopic, and cellular techniques. According to fluorescence and circular dichroism spectroscopies, Rebeccamycin interacted with ctDNA in the absence of H1 through intercalator or binding modes, while the presence of H1 resulted in revealing theintercalator, as the dominant role, and groove binding modes of ctDNA-Rebeccamycin complex. The binding constants, which were calculated to be 1.22 × 104 M-1 and 7.92 × 105 M-1 in the absence and presence of H1, respectively, denoted the strong binding of Rebeccamycin with ctDNA. The binding constants of Rebeccamycin with ct DNA in the absence and presence of H1 were calculated at 298, 303 and 308 K. Considering the thermodynamic parameters (ΔH0 and ΔS0), both vander waals forces and hydrogen bonds played predominant roles throughout the binding of Rebeccamycin to ctDNA in the absence and presence of H1. The outcomes of circular dichroism suggested the lack of any major conformational changes in ctDNA upon interacting with Rebeccamycin, except some perturbations in native B-DNA at local level. Additionally, the effect of NaCl and KI on ctDNA-Rebeccamycin complex provided further evidence for the reliance of their interaction modes on substituted groups. The observed increase in the relative viscosity of ctDNA caused by the enhancement of Rebeccamycin confirmed their intercalation and groove binding modes in the absence and presence of H1. Moreover, the assessments of molecular docking simulation corroborated these experimental results and also elucidated the effectiveness of Rebeccamycinin inhibiting and proliferating T24 and 5637 cells. Meanwhile, the ability of Rebeccamycin in inhibiting cell proliferation and tumor growth through the induction of apoptosis by down regulating the PI3K/AKT signaling pathway were provided.

Orange G degradation by heterogeneous peroxymonosulfate activation based on magnetic MnFe2O4/α-MnO2 hybrid

Wastewater containing an azo dye Orange G (OG) causes massive environmental pollution, thus it is critical to develop a highly effective, environmental-friendly, and reusable catalyst in peroxymonosulfate (PMS) activation for OG degradation. In this work, we successfully applied a magnetic MnFe₂O₄/α-MnO₂ hybrid fabricated by a simple hydrothermal method for OG removal in water. The characteristics of the hybrid were investigated by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller method, vibrating sample magnetometry, electron paramagnetic resonance, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The effects of operational parameters (i.e., catalytic system, catalytic dose, solution pH, and temperature) were investigated. The results exhibited that 96.8% of OG degradation was obtained with MnFe₂O₄/α-MnO₂(1:9)/PMS system in 30 min regardless of solution pH changes. Furthermore, the possible reaction mechanism of the coupling system was proposed, and the degradation intermediates of OG were identified by mass spectroscopy. The radical quenching experiments and EPR tests demonstrated that SO₄^•̶, O₂^•̶, and ¹O₂ were the primary reactive oxygen species responsible for the OG degradation. The hybrid also displayed unusual stability with less than 30% loss in the OG removal after four sequential cycles. Overall, magnetic MnFe₂O₄/α-MnO₂ hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.

Photocatalytic Aerobic Oxidation of Biomass-Derived 5-HMF to DFF over MIL-53(Fe)/g-C3N4 Composite

A MIL-53(Fe)/g-C₃N₄ heterogeneous composite was synthesized and applied in photocatalytic oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF). The systematic investigation indicated that the introduction of MIL-53(Fe) into g-C₃N₄ increased the specific surface area, broadened the visible-light response region, and promoted the separation efficiency of the photo-generated electron-hole pairs. The 10% MIL-53(Fe)/g-C₃N₄ heterogeneous composite achieved the best photocatalytic oxidation activity with 74.5% of 5-HMF conversion under simulated sunlight, which was much higher than that of pristine g-C₃N₄ and MIL-53(Fe). The MIL-53(Fe)/g-C₃N₄ composite displayed good photocatalytic reusability and stability. Based on the characterization results and photocatalytic performance, a Z-scheme photocatalytic mechanism of the MIL-53(Fe)/g-C₃N₄ composite was suggested, and a possible reaction route was deduced.

Ag@AgCl nanoparticles grafted on carbon nanofiber: an efficient visible light plasmonic photocatalyst via bandgap reduction

A novel silver@silver chloride/carbon nanofiber (Ag@AgCl/CNF) hybrid was synthesized by electrospinning, heat treament, and subsequentin situchemical oxidation strategy. The synthesized materials were characterized using x-ray diffraction, Fourier-transform infrared, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, and energy dispersive x-ray. The experimental results reveal that the electrospun AgNO₃/PAN was carbonized and reduced to Ag/CNF, the Ag/CNF was then partly oxidized to form Ag@AgCl/CNF in which Ag@AgCl nanoparticles (ca. 10-20 nm in diameter) were uniformly bounded to CNFs (ca. 165 nm in diameter). The obtained Ag@AgCl/CNF was employed for Na₂S₂O₈activation under visible light irradiation to treat Rhodamine B (RhB). A remarkable RhB removal of ca. 94.68% was achieved under optimal conditions, and the influence of various parameters on removal efficiency was studied. Quenching experiments revealed that HO•, SO₄^•-,¹O₂, and O₂^•-were major reactive oxygen species, in which O₂^•-played a pivotal role in RhB degradation. A possible mechanistic route for RhB degradation was proposed.

Strategies for improving the catalytic activity of metal-organic frameworks and derivatives in SR-AOPs: Facing emerging environmental pollutants

As persulfate activator, Metal organic frameworks (MOFs) and derivatives are widely concerned in degradation of emerging environmental pollutants by advanced oxygen technology dominated by sulfate radical () (SR-AOPs). However, the poor stability and low catalytic efficiency limit the performance of MOFs, requiring multiple strategies to further enhance their catalytic activity. The aim of this paper is to improve the catalytic activity of MOFs and their derivatives by physical and chemical enhancement strategies. Physical enhancement strategies mainly refer to the activation strategies including thermal activation, microwave activation and photoactivation. However, the physical enhancement strategies need energy consumption and require high stability of MOFs. As a substitute, chemical enhancement strategies are more widely used and represented by optimization, modification, composites and derivatives. In addition, the identification of reactive oxygen species, active site and electron distribution are important for distinguishing radical and non-radical pathways. Finally, as a new wastewater treatment technology exploration of unknown areas in SR-AOPs could better promote the technology development.

Synthesis of a UiO-66/g-C3N4 composite using terephthalic acid obtained from waste plastic for the photocatalytic degradation of the chemical warfare agent simulant, methyl paraoxon

In our study, Zr-based UiO-66 (Zr) was synthesized using terephthalic acid obtained from waste plastic. Thereafter, UiO-66/g-C₃N₄ composites were prepared by the solvothermal method, and their photocatalytic activity in the photodegradation of the chemical warfare agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP), was evaluated. The as-synthesized UiO-66/g-C₃N₄ exhibited a high surface area (1440 m² g⁻¹) and a high capillary volume (1.49 cm³ g⁻¹). The UiO-66/g-C₃N₄ samples absorbed a visible light band with bandgap energies of 2.13–2.88 eV. The as-synthesized UiO-66/g-C₃N₄ composites exhibited highly efficient degradation of DMNP with a short half-life (t_1/2 of 2.17 min) at pH 7 under visible light irradiation. The trapping experiments confirmed that the h⁺ and ˙O₂⁻ radicals played an important role in the photocatalytic degradation of DMNP. The UiO-66/g-C₃N₄ catalyst simultaneously performed two processes: the hydrolysis and photocatalytic oxidation of DMNP in water. During irradiation, a p–n heterojunction between UiO-66 and g-C₃N₄ restricted the recombination of photogenerated electrons and holes, resulting in the enhancement in the degradation rate of DMNP.

UiO-66/g-C₃N₄ with a high surface area (1440 m² g⁻¹) and a high capillary volume (1.49 cm³ g⁻¹) exhibited highly efficient degradation of dimethyl 4-nitrophenyl phosphate with t_1/2 = 2.17 min.