Intermediate Products Research Articles

The interaction between organic acids and green rust-Co(II): Mineralogical changes of green rust and redistribution of Co(II)

Green rust (GR), as a vital intermediate product during the formation of various iron oxides, exists with organic matters and metals contaminants in natural environments. Understanding the effects of these natural factors on the transformation process of GR into iron oxides and the environmental behaviors of heavy metals and organic matters during process are critical for environmental quality management, but the fundamental identification of the interaction mechanisms between them and GR is still challenging. In this study, the transformation mechanisms of Co-bearing green rust (GR-Co) synthesized by co-precipitation, and the redistribution behaviors of Co(II) in an environment containing oxalic acid (OA) and citric acid (CA) were clarified. The findings indicated that OA promoted the Fe(II) dissolution and the transformation of GR-Co to goethite, while CA decreased the Fe(II) dissolution and the proportion of non-extractable Co. Furthermore, in the presence of CA, the transformation products of GR-Co were ferrihydrite, magnetite, lepidocrocite and goethite instead of only lepidocrocite and goethite. Meanwhile, CA prohibited ferrihydrite from transforming into more highly crystalline iron minerals. The finding of this study improves the understanding of the interaction mechanisms between GR-Co and organic matter, and the environmental geochemical behaviors of Co and organic carbon during the transformation processes in nature.

Synergistic low-temperature plasma degradation of tetracycline with ferrocene

Low-temperature plasma technology has been successfully applied to the treatment of persistent organic pollutants in water. By combining catalysts with low-temperature plasma, the degradation efficiency and energy utilization efficiency of pollutants can be effectively improved. In this study, ferrocene (Fc) was added as a new catalyst to the low-temperature plasma system to treat tetracycline (TC) found in wastewater. The degradation efficiency of TC after 60 min of plasma treatment, Fc adsorption, and Fc/plasma treatment was compared, indicating that Fc/plasma improved the removal compared with using plasma alone. The effects of primary parameters such as Fc dosage, initial pH, discharge voltage, and anions in wastewater on TC removal efficiency were investigated. Under the conditions of Fc dosage of 400 mg/L, pH of 9, and discharge voltage of 20 kV, the degradation efficiency of TC was 76.59%. Results of free quenching experiments indicated that hydroxyl radicals played an important role in the treatment of TC. The characterizations of Fc showed that the structure of Fc before and after use in the plasma system changed little. In addition, toxicity testing using toxicity assessment software showed that only two to three degradation intermediate products had slightly higher toxicity than TC. The iron leaching concentration was 2.5 mg/L, and the Fc dissolution concentration was 1.72 mg/L after the reaction.

Photocatalytic Upcyclingof Plastic Waste into Syngas by ZnS/Ga2O3 Z-scheme Heterojunction.

The photocatalytic conversion of plastic waste into value-added products using solar energy presents a promising approach for promoting environmental sustainability. Nonetheless, the emission of CO2 during the conventional photocatalytic degradation process remains a major hurdle that impedes its further development. In this study, we propose an efficient photocatalytic conversion of polyethylene plastic into syngas (CO + H2 mixtures) by using a ZnS/Ga2O3 Z-scheme heterojunction photocatalyst. It is found that the strong redox capability of photogenerated holes and electrons in the Z-scheme heterojunction photocatalyst can promote the oxidative depolymerization of PE plastic, concurrently enabling the efficient reduction of the intermediate product CO2 into syngas. Furthermore, this system also demonstrates applicability in the conversion and upcycling of other polyolefin plastics including polypropylene and polyvinyl chloride. Our findings highlight the potential of polyolefin plastics photoreforming for the production of syngas under environmentally benign conditions.

Ulinastatin attenuates renal fibrosis by regulating AMPK/HIF-1α signaling pathway-mediated glycolysis.

Renal fibrosis is a common outcome of chronic kidney diseases and glycolysis drives the development of renal fibrosis in damaged kidneys. Ulinastatin (UTI) is a broad-spectrum protease inhibitor with anti-inflammatory and antioxidant properties with anti-fibrosis effects. In this study, we aimed to verify whether UTI could exert anti-renal fibrosis effects by inhibiting glycolysis and explored the potential mechanisms. Renal fibrosis was induced in mice via unilateral ureteral obstruction (UUO). Transforming growth factor-β1 stimulates human kidney proximal tubular epithelial cells to undergo fibrotic changes. Histopathological staining was used to observe the pathological changes in the kidneys. The levels of fibrosis biomarkers, glycolytic enzymes, and key signaling molecules were determined using gene and protein assays. Cellular energy metabolism was measured using Seahorse XF24 analyzer. Modulated the activity of adenylate-activated protein kinase (AMPK) and hypoxia-inducible factor-1α (HIF-1α) to confirm that AMPK can regulate HIF-1α-mediated glycolysis. Furthermore, UTI and AMPK knockdown were combined to verify whether UTI could attenuate glycolysis via the AMPK pathway. UTI pretreatment improved UUO-induced renal injury and fibrosis. The expression of fibrosis biomarkers and glycolytic enzymes was reduced by UTI at both mRNA and protein levels. UTI treatment decreased the rate of glycolysis and the production of glycolytic intermediates in fibrotic cells and tissues. Furthermore, AMPK can regulate HIF-1α-mediated glycolysis in renal tubular epithelial cells. Finally, the attenuation of glycolysis by UTI was related to AMPK/HIF-1α pathway, and this effect was inhibited by knockdown AMPK. UTI can effectively alleviate renal fibrosis, which may be partly attributed to the reduction of glycolysis by regulating AMPK/HIF-1α pathway.

Understanding Electrochemical Reaction Mechanisms of All-Electrochem-Active Mg2Si Electrode in All-Solid-State Batteries.

To better understand the electrochemical reaction mechanism of the Mg2Si electrode in all-solid-state batteries (ASSBs), a rational all-electrochem-active Mg2Si electrode is first designed to minimize the inactive component-related interfacial degradation. This is due to its unique mixed conductivity properties, including a high electronic conductivity of up to 8.9 × 10-2 S cm-1 and an ionic conductivity of 9.7 × 10-5 S cm-1, which allow for fast charges transport. In ASSBs, the Mg2Si electrode exhibits a higher initial Coulombic efficiency of 83.5% at 300 mA g-1 compared with the Si electrode (72.3%). X-ray diffraction and X-ray photoelectron spectroscopy results demonstrate that intermediate products (LixMg2Si, Li-Si alloy, and Li-Mg alloy) can form when the Mg2Si electrode discharges to 0.01 V, and partial Mg2Si still does not react with lithium. This work provides valuable insights into the reaction mechanisms and guides optimization strategies for developing next-generation Si-based ASSBs.

Inhibition of Polycyclic Aromatic Hydrocarbons Formation During Supercritical Water Gasification of Sewage Sludge by H2O2 Combined with Catalyst

This work evaluated the alterations in the levels and types of polycyclic aromatic hydrocarbons (PAHs) within both liquid and solid products throughout the process of the catalytic supercritical water gasification of dewatered sewage sludge to examine the catalytic effect of various catalysts and the inhibit reaction pathways. The addition of Ni, NaOH, Na2CO3, H2O2, and KMnO4 reduced the concentrations of PAHs, with Ni and H2O2 showing the best performance. The concentrations of PAHs, especially higher-molecular-weight compounds in the residues, decreased sharply as the H2O2 amount increased. At a 10 wt% H2O2 addition, the levels of PAHs in the liquid and solid products were reduced by 91% and 88%, respectively. High-ring PAHs were not detected in the residues as the H2O2 amount increased to an 8 wt%. H2O2 addition evidently inhibits PAH formation by promoting the ring-opening reactions of initial aromatic compounds in raw sludge and inhibiting the polymerization of open-chain intermediate products. The addition of NaOH + H2O2 or Ni + H2O2 as combined catalysts significantly lowered PAH concentrations while increasing the H2 yield. The addition of 5 wt% Ni + H2O2 reduced PAH concentrations in the liquid and solid residues by 70% and 44%, respectively, while the H2 yield escalated from 0.13 mol/kg OM to 3.88 mol/kg OM. Possible mechanisms associated with the reaction pathways of these combined catalysts are proposed.

Exploration of Pseudomonas knackmussii AD02 for the biological mitigation of post-harvest aflatoxin contamination: Characterization and degradation mechanism

Aflatoxins, known for their potent carcinogenic and mutagenic properties, pose a major threat to human and animal health. Due to the impacts of climate change, aflatoxin contamination has emerged as a critical food safety issue, necessitating the development of effective detoxification strategies to mitigate its severe health risks. The current isolated, identified, and characterized bacterial strains from peanut-growing soils that are capable of degrading aflatoxin B1 (AFB1). Coumarin was used as a selective carbon source during isolation. Bacterial isolate AD02 had the highest AFB1 degradation efficiency (88.85%). Morphological and genetic analyses confirmed AD02 as a Gram-negative, rod-shaped bacterium closely related to Pseudomonas knackmussii. Optimization studies using a Box-Behnken design showed that initial pH significantly affected AFB1 degradation, with the optimal conditions identified as pH 7, 25 °C, and 24 h of incubation, resulting in approximately 90% AFB1 degradation. Additionally, P. knackmussii AD02 simultaneously degraded a mixture of AFB1, AFB2, AFG1, and AFG2. A mechanistic study of AFB1 degradation revealed the role of extracellular enzymes, particularly in proteinaceous and membrane-associated components. The mechanism for AFB1 degradation involved the hydrolytic cleavage of the lactone ring in the coumarin moiety, followed by the cleavage of the cyclopentenone ring and the elimination of double bonds in the furan and coumarin moieties. The in silico predictions indicated that this bacterium could metabolize AFB1 into a non-mutagenic and non-carcinogenic intermediate product. This study represents the first report on aflatoxin degradation by P. knackmussii, highlighting its potential as an effective biological agent for aflatoxin detoxification.

Optimization and reusability of photocatalytic g-C3N4/W-TiO2/PVDF membranes for degradation of sulfamethazine.

Pharmaceuticals and personal care products (PPCPs) are prevalent emerging pollutants in the aquatic environment. The photocatalysis process has proven high efficiency in degrading PPCPs; however, the fate and repercussions of photocatalyst residuals are a major concern. To avoid that, we developed a composite from graphitic carbon nitride/tungsten doped with titanium dioxide (g-C3N4/W-TiO2) and loaded it on polyvinylidene fluoride (PVDF) membranes by the phase-inversion method. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and other different analyses implied the successful synthesis of g-C3N4/W-TiO2 composite and coating on PVDF membranes. A Box-Behnken design (BBD) was used to optimize the operational parameters, including pH, g-C3N4 ratio in the composite, and initial SMZ concentration by the response surface methodology (RSM). The highest SMZ degradation percentage was 98.60% after 240min of irradiation. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) along with suspect screening was used to identify the intermediate transformation products and propose the SMZ degradation pathway. The loss in membrane activity after five cycles of photocatalytic degradation was about 18%. According to the current study, the photocatalytic membrane g-C3N4/W-TiO2/PVDF is promising for removing sulfonamide antibiotics from wastewater.

Mechanisms and perspectives of B vitamins associated one carbon metabolism on colorectal cancer risk

Colorectal cancer (CRC) represents a significant global health challenge as a common malignancy of the digestive tract. The involvement of B vitamins-specifically folic acid (B9), riboflavin (B2), pyridoxine (B6), and cobalamin (B12)-is crucial in metabolic processes by mediating the transfer of one-carbon (1C) units, which plays a fundamental role in cellular functions and tumor growth. 1C metabolism is involved in synthesis of proteins, lipids, nucleic acids, and other cofactors. 1C metabolism, intertwined with the metabolism of other nutrients, forms complex pathways where B vitamins act as precursors or coenzymes, influencing the production of various intermediates. These vitamins, as essential nutrients, are implicated to varying the pathogenesis and progression of colorectal cancer such as epigenetics. Furthermore, 1C metabolism affects tumor cell fate through multiple aspects including nucleotide synthesis, redox homeostasis, and the interaction with gut microbiota. Given these roles, understanding and monitoring B vitamin levels and their metabolic pathways are essential for colorectal cancer prevention and management. This approach not only helps in reducing tumor-related mortality but also opens new avenues for research into CRC mechanisms and potential therapeutic strategies.

The indirect global warming potential of methane oxidation in the IPCC’s sixth assessment report

Abstract Greenhouse-gas emission (GHG) metric values for methane in the sixth assessment report by the Intergovernmental Panel on Climate Change (IPCC) include the indirect effect associated to the oxidation of methane to CO2. An analysis of the figures provided by the IPCC reveals they assume that in average 75% of methane is ultimately oxidized to CO2, while the remaining 25% is converted to intermediate degradation products, most notably formaldehyde, which are removed from the atmosphere via wet and dry deposition and treated by the IPCC as a potential carbon sink in terrestrial and aquatic ecosystems. In this short article we present a critique to this assumption, based on existing knowledge about the environmental fate of methane’s degradation products. We conclude that any assumption other than full degradation of methane to CO2 in a rather short time frame is questionable, whereby the default CO2 yield from this oxidation, as far as GHG metrics are concerned, should be 100%. We re-calculate values for the global warming potential (GWP) metric in accordance with our findings, resulting in an increase in GWP100 from 29.8 and 27.0 to 30.40 and 27.65 kg CO2-equivalents/kg fossil and biogenic methane, respectively. Although we only present the implications in terms GWP, our proposal is conceptually valid for other GHG metrics as well.

Unusual and Persistent Free Radical Intermediate Production from 2-Pyridyl Ketones via UV Irradiation: A Direct ESR Study.

Aryl ketones are often used as photosensitizers and photoinitiators. Free radical intermediates have been suggested, but not confirmed, to be generated after photoirradiation. Here we found, unexpectedly, that a persistent radical was produced from di-2-pyridyl ketone after UV irradiation, which was detected by the direct ESR method. Interestingly, the persistent radical was very sensitive to oxygen and the pH of the reaction medium. A similar persistent radical was also observed from phenyl-2-pyridyl ketone, but not from 3-benzoylpyridine, 4-benzoylpyridine, and benzophenone, suggesting that the presence of a carbonyl group connected to the ortho-position of the pyridine ring is critical for such radical production. By complementary applications of ESR, HPLC, and ESI-Q-TOF-MS, the possible chemical structures of the persistent radical and final product were identified, and the possible underlying reaction mechanism was proposed. This represents the first report on UV-induced persistent radical generation from 2-pyridyl ketones, which should be of great significance for future studies.

Analysis of GCRV Pathogenesis and Therapeutic Measures Through Proteomic and Metabolomic Investigations in GCRV-Infected Tissues of Grass Carp (Ctenopharyngodon idella).

Hemorrhagic disease caused by grass carp reovirus (GCRV) infection is a major problem affecting the grass carp aquaculture industry. Therefore, inhibiting the spread of GCRV infection is of great economic significance. Herein, we sequenced five tissues (gill, liver, intestine, kidney, and muscle) from grass carp before and after GCRV infection using data-independent acquisition proteomic and untargeted metabolomic technologies, and quantitatively identified 10,808 proteins and 4040 metabolites. Then, we analyzed the differentially expressed proteins (DEPs) and metabolites (DEMs) before and after GCRV infection in the five tissues. Gene ontology analysis revealed that the five tissue DEPs were enriched in metabolic, including carbohydrate and lipid metabolic processes. Chemical taxonomy analysis showed that the categories of DEMs mainly included carbohydrates and lipids, such as fatty acids, glycerophospholipids, steroids, and their derivatives. Both the proteomic and the metabolomic data showed that GCRV affected the carbohydrate and lipid metabolism in the host. Shared pathway analysis was performed at both the protein and metabolic levels, showing significant enrichment of the glycolysis and pentose phosphate pathways (p < 0.001). Further analysis of glycolysis and pentose phosphate pathway inhibitors revealed that these two pathways are important for GCRV replication. As the kidney was the most affected among the five tissues, we analyzed the butanoate metabolism in the kidney, which revealed that most of the differentially expressed proteins and differently expressed metabolites in the butanoate metabolism were related to the TCA cycle. Further investigation showed that fumaric acid, an intermediate product in the TCA cycle, significantly inhibited GCRV replication in the CIK cells (p < 0.001), and that this inhibitory effect may be related to its induction of interferon system activation. The addition of fumaric acid to feed increased the survival rate of juvenile grass carp by 19.60% during GCRV infection, and protected the tissues of those infected with GCRV, making it a potential anti-GCRV feed additive. Our results provide new perspectives on GCRV pathogenesis and antiviral strategies for grass carp.

A fine-scale atlas reveals the systematic imbalance between carbon emissions and economic benefits along value chain within China

In efforts to achieve the aspiring carbon mitigation goals, China is actively seeking to reconcile the economic development and carbon reduction with diverse regional conditions. Here, we firstly integrated a national-wide atlas on the labor division of production, and decomposed value added and carbon emission along China's domestic value chain during 2007–2017. We found that the value chain roles lead to a systematic imbalance between value added and carbon emissions across regions. Over 70 % of sufferers of the inequality were located at the north, most of which were in the upstream position to supply resource and energy intermediate products of higher on-site emissions and relatively less value added in comparison to the downstream manufacturing and service products production at the coastal regions. As a result, the northern inland suffered a great deal while part of coastal regions and southern inland were beneficiaries in the participation in domestic value chain. In particular, several regions inevitably undertake industries with higher emission intensity and less gains in a sound domestic industrial chain. These strongly call for a systematically policy- or price-based mechanism to explore fair strategy for emission reduction.

Combination of Hollow Capsule Structure and Zn Uniform Load for the Conversion of Methanol to Aromatics over Zn/ZSM-5 Zeolites.

As an important nonoil route for acquiring aromatics, the highly efficient conversion of methanol to aromatics over Zn/ZSM-5 zeolites remains an ongoing challenge. In this work, we developed a uniform loading approach of zinc and further combined it with a hollow capsule structure to design the high-performance Zn/ZSM-5 catalyst. The electrostatic assembly among EDTA3-, n-butylamine+ and negative silica-alumina gel gave rise to an "Inorganic-Organic Hybrid Sphere" in form of Na(l+m+n+3x)-(y+z)·{[(SiO)4Al-]l/(SiO-)m(n-butylamine+)y(EDTA3-)x(n-butylamine+)z(SiO-)n, which further transformed into mesoporous aluminosilicates sphere (MASS) through calcination. The characteristic of abundant mesopore guaranteed MASS fantastic ability to evenly incorporate Zn ingredient inside, and the resultant Zn/MASS further served as a "hard template" for the direct synthesis of Hollow Zn/ZSM-5 capsules, rather than after impregnation. When tested in the methanol-to-aromatics (MTA) process, the direct synthesis method not only facilitated the homogeneous dispersion of the Zn ingredient, but also benefited for the generation of more (ZnOH)+ sites and strengthened their synergism with zeolite acid for the superior aromatics selectivity (50.63%). Meanwhile, the hollow capsule structure increased the contact time of MTA intermediate products with the Zn/ZSM-5 shell, and it increased the coke-admitting capacity and suppressed the coke rate, which maintained quite an excellent stability (131 h). Therefore, the above combination of hollow capsule structure and uniform load of Zn ingredient brings forward a wide prospect to develop zeolite materials with excellent properties in catalysis.

Microbial Ecology of Denitrification Process and Its Application in Wastewater: Treatment, Challenges and Opportunities

Denitrification is a crucial microbial process in the nitrogen cycle, transforming nitrate (NO₃⁻) into nitrogen gas (N₂), thereby mitigating nitrogen pollution in aquatic ecosystems. This microbial activity plays a vital role in wastewater treatment by removing excess nitrogen, which contributes to eutrophication and water contamination. The denitrification process involves various microbial communities, including bacteria such as Pseudomonas, Paracoccus, and Bacillus, which operate under anoxic conditions to achieve nitrogen reduction, an optimizing denitrification in wastewater treatment presents several challenges, such as maintaining ideal environmental conditions (e.g., carbon availability, oxygen levels, pH) and overcoming issues related to incomplete denitrification, which can lead to the production of harmful intermediates like nitrous oxide (N₂O). Despite these hurdles, recent advancements in microbial ecology, such as the use of biofilms, bioreactors, and genetic engineering, offer promising opportunities to enhance denitrification efficiency. This review explores the microbial ecology of the denitrification process, its application in wastewater treatment, and the challenges and opportunities associated with its practical implementation in reducing nitrogen pollution.

Effect of reduced flaxseed cyclic peptide [1–9-NαC]-linusorb B2 (CLB) and its oxidized form on the oxidative stability of flaxseed oil

This study aimed to explore the antioxidant capacity and mechanism of cyclic peptide [1–9-NαC]-linusorb B2 (CLB) and its oxidized form ([1–9-NαC],[1-MetO]-linusorb B2 (CLC),[1–9-NαC],[1-MetO2]-linusorb B2 (CLK)) in flaxseed oil (FSO). The results showed that CLB delayed the oxidation of FSO (containing Cu2+) in the initial stage of accelerated oxidation, whereas CLK accelerated the oxidation, leading to an increase of 25 % in AV and 33 % in POV (P < 0.05). In molecular docking, the binding ability of cyclic peptides to metal ions and intermediate oxidative products such as aldehydes tends to decrease when CLB oxidized to CLC, then CLK. CLK had the poorest binding capacity with the most serious oxidation on FSO. In conclusion, the antioxidant capacities of CLB and its oxidized form were contributed by their reducing ability as well as their binding ability to metal ions and intermediate oxidative products of fatty acids.

Fabrication of polydopamine doped helical/chiral porous carbon fiber (HPCFs@PDA) and N-doped carbon layers (HPCFs@NCLs) for their application as wave absorber with ultrawide EAB

A new class of wave absorbing materials HPCFst@PDA and HPCFst@NCLs (where HPCFs describes helical/chiral porous carbon fiber, t refers to carbonization 700, 800 °C, PDA ascribed to poly (dopamine), and NCLs corresponds to nitrogen doped carbon layers) with helical/chiral, hierarchical, multi-layered structural morphology containing different heterostructures was triumphantly constructed through single-step carbonization of HPCFst. The HPCFst biomass fiber was go through self-polymerization of dopamine and we get HPCFs700@PDA, HPCFs800@PDA as an intermediate product. Finally, the PDA doped HPCFs biomass (HPCFs700@PDA, HPCFs800@PDA) was effectively transformed into NCLs from inside toward outside (HPCFs700@NCLs, HPCFs800@NCLs) through carbonization. Notably, HPCFs exhibit helical/chiral, hierarchical porous morphology with hetero-interfaces (such as dipole interfaces) that improve dielectric loss, while PDA and NCLs ameliorate wave absorber conductivity, through generation of polarization centers, heterointerfaces and resulting in considerable dielectric loss. Moreover, HPCFs with such unique structural morphology provide additional loss mechanism through cross-polarization that improve dissipation/attenuation of microwave. The microwave absorption mechanism of HPCFst@PDA(1–3), HPCFst@NCLs(1–3) (where 1, 2, 3 refer to filler content 27.50, 30.00, 32.50%wt PDA derived absorber and 20.00, 22.50, 25.00%wt NCLs filler) and their structure active relationship are further elucidated. Evidently, HPCFs700@PDA2 gained reflection loss (RL) of −51.60 dB at 13.60 GHz, across the broad spectrum of frequencies (EAB, RL ≤ −10 dB) covers 6.70 GHz (11.30–18.00 GHz) at 2.70 mm thickness. The EAB ameliorate to the value of 7.20 GHz (10.70–18.00 GHz) at thickness of 2.80 mm. While HPCFs700@NCLs2 RL was improved to −63.00 dB at 2.40 mm thickness with EAB 5.10 GHz (11.40–16.50) at 13.30 GHz frequency. Likewise, HPCFs800@PDA2 RL elevates to the value of −53.40 dB with adequate EAB covering 12.80–18.00 GHz (5.20 GHz) at higher values of 14.40 GHz and 2.10 mm thickness. For HPCFs800@NCLs2, the RL is as high as −65.40 dB at 9.90 GHz, with an effective thickness of 3.20 mm covering 7.50–11.20 GHz (3.20 GHz) EAB. At matching thickness of 2.00 mm the EAB covers 13.80–18.00 (4.20 GHz). Their top-notch microwave absorption capabilities with widened EAB at lower matching thickness demonstrate potentially promising prospects of HPCFst@PDA and HPCFst@NCLs as wave absorbing materials.

CuO/Cu(OH)2@g-C3N4 derived from CuBTC/g-C3N4 for two channel photocatalytic hydrogen peroxide production

Photocatalytic production of H2O2 is indeed a safe, sustainable and cost-effective technology, offering an environmentally friendly solution to the energy crisis through solar photocatalysis. However, it still faces challenges such as reliance on organic electron donors and pure O2, as well as inefficiencies in hole utilization. To overcome these limitations, a dual-channel photocatalytic system has been developed. In this study, we showcase the efficiency of the CuO/Cu(OH)2@g-C3N4 composite, derived from CuBTC/g-C3N4 via NaOH treatment, as a high-performance dual-channel photocatalyst for H2O2 production. Under visible light (λ ≥ 420 nm), this composite achieves a H2O2 yield of 1354 μmol/L in 120 min without any sacrificial agent, outperforming g-C3N4 by 8.4 times, CuO by 13.6 times and CuO@g-C3N4 by 1.9 times. Quenching experiments and electron paramagnetic resonance spectra confirmed that HO• and O2•− are intermediate products in the photocatalytic process, following a two-step single-electron reaction pathway. The superior activity of CuO/Cu(OH)2@g-C3N4 in H2O2 generation can be attributed to the synergistic effects of OH bonds on the CuO@g-C3N4 Z-type heterojunction and Cu(OH)2. This research presents a straightforward and promising approach for developing highly efficient photocatalysts for energy conversion.

Degradation study of δ-hexachlorocyclohexane by iron sulfide nanoparticles: elucidation of reaction pathway using compound specific isotope analysis and pH variation

pH influences the reactivity of iron (II) minerals towards halogenated pollutants like hexachlorocyclohexanes (HCHs). To explore these incompletely understood interactions, we investigated the carbon isotope fractionation of the δ-HCH isomer during dehalogenation by iron sulfide at pHs spanning a pH range across slightly acidic to alkaline domains (5.8 to 9.6). The δ-1,3,4,5,6-pentachlorocyclohex-1-ene (δ-PCCH) was the intermediate degradation product, while benzene, monochlorobenzene (MCB), but especially 1,2-dichlorobenzene (1,2-DCB), and 1,2,4-trichlorobenzene (1,2,4-TCB), were the main degradation products of δ-HCH. These degradation products suggested dehydrochlorination as the main degradation pathway of δ-HCH by iron sulfide. Different kinetic experiments indicate that the rate constants (ka) during dechlorination of δ-HCH by iron sulfide rose with pH: 0.003 d-1 (pH 5.8) < 0.034 d-1 (pH 8) < 0.085 (pH 9.3) < 0.286 d-1 (pH 9.6). Upon Rayleigh model calculations, an enrichment factor (εC) of -7.8 ± 1.0 ‰ was calculated for δ-HCH dehalogenation by FeS at pH 8.0. This suggests an apparent kinetic isotope effect (AKIEC) value of 1.049 ± 0.006 for dehydrohalogenation. The magnitude of the isotope effect from this paper furthermore supports dehydrohalogenation and opens the possibility to study the degradation of HCHs by iron (II) minerals containing FeS as mackinawite in oxygen-deprived environments.

Investigation of efficient adsorption-electrochemical degradation performance of ZIF-8/MWCNTs nanocomposites toward 2,4-dichlorophenol

The highly toxic and recalcitrant organic pollutant, 2,4-dichlorophenol (2,4-DCP), is commonly found in wastewater. Therefore, it is critical to investigate novel techniques for the efficient removal of 2,4-DCP from wastewater. The present study employed a one-step synthesis method to fabricate ZIF-8/multi-walled carbon nanotubes (ZIF-8/MWCNTs) nanocomposites with well-defined mesoporous structures, which were subsequently coated onto carbon cloth (CC) to form the anode ZIF-8/MWCNTs/CC. Subsequently, the adsorption performance of ZIF-8/MWCNTs toward 2,4-DCP and the adsorption-electrochemical degradation performance of ZIF-8/MWCNTs/CC toward 2,4-DCP were investigated. ZIF-8/MWCNTs exhibit exceptional adsorption capacity and rate toward the 2,4-DCP. At 303 K, it achieved a saturated adsorption amount as high as 1056.78 mg·g−1 within only 30 min of reaching equilibrium. Moreover, when coated on CC substrates, the internal pore structure of ZIF-8/MWCNTs is effectively exploited during the adsorption. In addition, the incorporation of MWCNTs enhances the conductivity of the ZIF-8/MWCNTs/CC electrodes, leading to reduced resistance and improved electron transfer rate. Notably, ZIF-8/MWCNTs/CC enabled complete removal of a 25 mg·L-1 solution of 2,4-DCP within only 90 min and a 50 mg · L-1 solution within 120 min. Furthermore, the degradation mechanism of 2,4-DCP was analyzed by means of DFT modeling theoretical calculations and intermediate product determination analysis, while evaluating the toxicity of the generated material was evaluated. This study provides improved solutions and strategies for the treatment of chlorophenolic compound pollution in wastewater.