Electronic coupling of iron-cobalt in Prussian blue towards improved peroxydisulfate activation.

Prussian blue analogs (PBAs) have attracted extensive attention in the field of aqueous organic degradation due to the tremendous potential for peroxydisulfate (PDS) activation. However, the relationship between the d-band center of the catalyst and the activation behavior of PDS remained largely unexplored. Herein, a series of Fe-Co PBAs-based catalysts with different Fe/Co ratios (Fe-Co PBAs-1 = 1: 0.52; Fe-Co PBAs-2 = 1: 1.21, and Fe-Co PBAs-3 = 1: 1.48) have been prepared by a facile hydrothermal procedure and subsequent acid treatment (Fe-Co PBAs-xH). The as-prepared Fe-Co PBAs-xH exhibited superior PDS activation performance and excellent recyclability in the degradation of methylene blue (MB). Density functional theory calculations revealed that the electron-occupied state of the Fe-Co PBAs was shifted to the Fermi level, indicating a strong interaction and easier electron transfer. Moreover, the d-band center of Fe-Co PBAs was upshifted relative to that of Fe PBAs, suggesting easier adsorption of MB and PDS, which was beneficial to enhancing catalytic activation and subsequent dissociation. Radicals such as •OH, 1O2, O2•-, and SO4•- were determined by the radical quenching experiment and electron paramagnetic resonance (EPR) testing in the Fe-Co PBAs-3H/PDS system, and the order of MB degradation by the free active radical is •OH > 1O2 > O2•- > SO4•-. The degradation pathway and potential ecotoxicity of MB and its intermediates were also studied. This work can provide new insights to construct the efficient catalysts for the activation of PDS and the degradation of organic pollutants.

Visible-light-driven peroxydisulfate activation by biochar-loaded Fe-Cu layered double hydroxide for penicillin G degradation: Performance, mechanism and application potential.

The biochar-loaded Fe-Cu layered double hydroxide (FeCu-LDH@BC) catalyst was synthesized via a simple hydrothermal method and used to activate peroxydisulfate (PDS) for penicillin G (PG) degradation under visible light. The physicochemical properties of FeCu-LDH@BC were characterized using SEM, XPS, UV-DRS, SEM-EDS, HRTEM, XRD, BET, PL spectrum, FT-IR, Raman spectrum, TG-DSC, TPD, and EIS, showing that biochar (BC) enhanced the optical properties of FeCu-LDH. Notably, the FeCu-LDH@BC + PDS + Light system achieved a 98.79% degradation efficiency for PG in just 10 min. Furthermore, FeCu-LDH@BC retained excellent activity after four reuse cycles. LSV results indicated enhanced electron transfer in the FeCu-LDH@BC + PDS + Light system, suggesting a synergistic effect between the photocatalytic and PDS activation systems. The interconversion of h+, SO4·â», 1O2, and ·OH species was found to play a key role in PG degradation. Density functional theory was used to identify PG sites susceptible to radical attack, and the possible degradation pathway was proposed based on liquid chromatography-mass spectrometry results. Toxicity evaluation using the TEST software confirmed that the intermediates formed were significantly less toxic than PG. Lastly, the FeCu-LDH@BC + PDS + Light system removed 37.45% of total organic carbon and 63.74% of chemical oxygen demand from real wastewater within 120 min. The type and transformation pathways of organic matter in the wastewater were analyzed using 3D Excitation Emission Matrix spectroscopy to assess the system's application potential.

MoS2 coupled with ball milling co-modified sludge biochar to efficiently activate peroxymonosulfate for neonicotinoids degradation: Dominant roles of SO4•-, 1O2 and surface-bound radicals.

An efficient catalyst of molybdenum disulfide (MoS2) coupled with ball milling modified sludge biochar (BMSBC) was prepared to efficiently activate peroxymonosulfate (PMS) for neonicotinoids elimination. As expected, 95.1% of imidacloprid (IMI) was degraded by PMS/BMSBC system within 60 min and it was accompanied by the outstanding mineralization rate of 71.9%. The superior pore structures, rich defects, oxygen-containing functional groups and grafted MoS2 on BMSBC offered excellent activation performance for PMS. The influencing factor experiments demonstrated that PMS/BMSBC system performed high anti-interference to wide pH range and background constituents (e.g., inorganic ions and humic acid). Quenching experiments and electron paramagnetic resonance analysis revealed that SO4•-, 1O2, and surface-bound radicals played critical roles in IMI degradation. Electron donors on biochar activated PMS, producing surface radicals. The lone pair electrons within the Lewis basic site of C=O on BMSBC enhanced PMS decomposition by facilitating the cleavage of the -O-O- bond in PMS to release 1O2. The activation process of PMS by MoS2 accelerated the oxidation of Mo (IV) to Mo (VI) to generate SO4•-. Based on the transformed products (TPs), four degradation pathways of IMI in PMS/BMSBC system were suggested, and all TPs toxicity levels were lower than that of IMI by ECOSAR analysis. Additionally, BMSBC exhibited outstanding sustainable catalytic activity towards PMS activation with the well accepted degradation rate of 71.3% for IMI even after five reuse cycles. PMS/BMSBC system also exhibited satisfactory degradation rates (>71.8%) for IMI in various real waters (e.g., sewage effluent and livestock wastewater). Furthermore, PMS/BMSBC system also offered a favorable broad-spectrum elimination performance for other typical neonicotinoids (e.g., thiamethoxam, clothianidin, thiacloprid) with the degradation rates over 98%. This study has developed a desirable neonicotinoids purification technology in view of its high degradation/mineralization rate, outstanding detoxification performance, satisfied anti-interference to ambient conditions and sustainable sludge management.

Enhanced Dechlorination of the Herbicide Acetochlor by an Anaerobic Consortium via Sulfate Acclimation.

Acetochlor residues can contaminate anoxic habitats where anaerobic microbial transformation dominates. Herein, a highly efficient anaerobic acetochlor-degrading consortium ACT6 was enriched using sulfate and acetochlor as selection pressures. The acclimated consortium ACT6 showed an 8.7-fold increase in its ability to degrade acetochlor compared with the initial consortium ACT1. Two degradation pathways of acetochlor were found: reductive dechlorination and thiol-substitution dechlorination in the chloroacetyl group, in which the latter dominated. Acclimation enhanced the abundances of Desulfovibrio, Proteiniclasticum, and Lacrimispora from 0.7 to 28.0% (40-fold), 4.7 to 18.1% (4-fold), and 2.3 to 12.3% (5-fold), respectively, which were positively correlated with sulfate concentrations and acetochlor degradation ability. Three acetochlor-degrading anaerobes were isolated from the acclimated consortium ACT6, namely Cupidesulfovibrio sp. SRB-5, Proteiniclasticum sp. BAD-10, and Lacrimispora sp. BAD-7. This study provides new insights into the anaerobic catabolism of acetochlor and the anaerobic treatment of acetochlor in wastewater.

Biogenic ROS mediated degradation mechanism of marine toxin domoic acid.

Domoic acid (DA) is a compound generated as a secondary metabolite during harmful algal blooms, has historically received attention as the potent neurotoxicity in marine environment. However, the aerobic degradation mechanism of DA and the DA-degrader remain largely unknown. Here, we revealed the mechanism of aerobic degradation of DA by a ubiquitous marine Pseudoalteromonas sp., and more importantly, we confirmed that the degradation of DA is mediated by biogenic reactive oxygen species (ROS), rather than direct enzyme-mediated as traditionally conceived. Results indicated that DA degradation was caused by biogenic O2- and OH, where DA underwent reactions of decarboxylation, hydroxylation, and oxidation to yield the detoxification terminal product. Besides, whole genome sequencing and RT-qPCR analysis revealed that the genes conferring to encoding leucine dehydrogenase (ldh) and Na+-translocated NADH-quinone oxidoreductase (nqrA, nqrF) are responsible for biogenic ROS production. Finally, we found through comparative proteomic analysis that biogenic ROS mediated the DA degradation may be prevalent in the environment. Overall, this work not only reveals aerobic biotransformation mechanism of DA, but also identifies a novel mechanism of DA degradation, which provides new perspective into the environmental fate of DA and the artificial bioremediation of DA.

Metabolic signatures of metabolites of the purine degradation pathway in human plasma using HILIC UHPLC-HRMS.

The metabolic disorders in the purine degradation pathway have proven to be closely associated with several human diseases. However, the etiology is not yet fully understood. Profile assay of purine intermediates and uric acid involved in the metabolic pathway can provide additional insight into the nature and severity of related diseases. Purine metabolites are endogenous chemicals with high hydrophilicity, polarity, and similar structures, thus there is a great need for a specific method to quantify them directly in biological fluids with a short running time. Herein, eight purine degradation pathway metabolites, including xanthine, hypoxanthine, guanine, xanthosine, inosine, guanosine, adenosine and uric acid, in human plasma were quantitatively measured using hydrophilic interaction chromatography-tandem high-resolution mass spectrometry (HILIC-HRMS) in a short running time of 10 min. The method was systematically validated for specificity, linearity of the calibration curve, the limit of detection, the limit of quantification, the lower limit of quantification, precision, accuracy, extraction recovery, matrix effect, and stability. The results showed that the method was linear (R2 > 0.99), accurate (the intra- and inter-day recoveries of all analytes ranged from 90.0 % to 110.0 %), and precise (the intra- and inter-day precisions were less than 6.7 % and 8.9 %, respectively) with the lower limits of quantification ranging from 3 to 10,000 ng/mL. The extraction recoveries and matrix effects were repeatable and stable. All the analytes were stable in the autosampler and could be subject to three freeze-thaw cycles. The developed method was ultimately applied to 100 plasma specimens from healthy individuals. The results showed that the concentrations of different purine metabolites varied dramatically in plasma specimens. Diet and body mass index (BMI) were the most significant factors determining purine levels, followed by drinking and sex. Age, smoking and bedtime showed a very weak correlation with purine metabolism. The findings of the present work reveal the characteristics of purine metabolism in human plasma under non-pathological conditions. The results also highlight the factors that can cause changes in purine metabolism, which are useful in developing effective treatment strategies for metabolic disorders of purines, particularly for those caused by lifestyle factors.

Screening of polyurethane-degrading microbes using a quenching fluorescence probe by microfluidic droplet sorting.

Excessive use of polyurethane (PU) polymers has led contributed to serious environmental pollution. The plastic recycling technology using microorganisms and enzymes as catalysts offers a promising green and low-carbon approach for managing plastic waste. However, current methods for screening PU-degrading strains suffer from drawbacks such as being time-consuming and inefficient. Herein, we present a novel approach for screening PU-degrading microorganisms using a quenching fluorescent probe along with the fluorescence-activated droplet sorting (FADS). The FPAP could specifically recognize the 4,4'-methylenedianiline (MDA) derivates released from PU degradation, with fluorescence quenching as a response. Based on the approach, we successfully screen two PU-degrading strains (Burkholderia sp. W38 and Bacillus sp. C1). After 20 d of cultivation, strain W38 and C1 could degrade 41.58% and 31.45% of polyester-PU film, respectively. Additionally, three metabolites were identified during the degradation of PU monomer (2,4-toluene diamine, 2,4-TDA) and a proposed degradation pathway was established. Consequently, the fluorescence probe integrated with microfluidic droplet systems, demonstrates potential for the development of innovative PU-biocatalysts. Furthermore, the identification of the 2,4-TDA degradation pathway provides valuable insights that can propel advancements in the field of PU biodegradation.

Anaerobic fermentation for hydrogen production and tetracycline degradation: Biodegradation mechanism and microbial community succession.

The misuse and continues discharge of antibiotics can cause serious pollution, which is urgent to take steps to remit the environment pollution. In this study, anaerobic bacteria isolated from the aeration tank of a local sewage treatment plant were employed to investigate hydrogen production and tetracycline (TC) degradation during anaerobic fermentation. Results indicate that low concentrations of TC enhanced hydrogen production, increasing from 366 mL to a maximum of 480 mL. This increase is attributed to stimulated hydrolysis and acidogenesis, coupled with significant inhibition of homoacetogenesis. Furthermore, the removal of TC, facilitated by adsorption and biodegradation, exceeded 90 %. During the fermentation process, twenty-one by-products were identified, leading to the proposal of four potential degradation pathways. Analysis of the microbial community revealed shifts in diversity and a decrease in the abundance of hydrogen-producing bacteria, whereas bacteria harboring tetracycline resistance genes became more prevalent. This study provides a possibility to treat tetracycline-contaminated wastewater and to produce clean energy simultaneously by anaerobic fermentation.

Photocatalytic degradation of organophosphorus flame retardants in aqueous solutions: a review and future prospects.

The widespread use of organophosphorus flame retardants (OPFRs) in industrial and household products increases the risk of their environmental exposure, posing a serious threat to ecosystems and human health. Photocatalytic technology has been widely used in wastewater treatment due to its high efficiency, mild reaction conditions, and robustness. This review summarizes the current status of research on photocatalytic degradation of OPFRs, focusing on the effect of different types of catalysts on the degradation efficiency, the effects of pH, and co-existing inorganic and organic ions. And pH and co-existing inorganic mainly affect the active oxygen and the active surface sites of the catalyst. In addition, toxicological calculations of the intermediates of the degradation pathway using T.E.S.T. and ECOSAR showed that photocatalysis could effectively reduce the toxicity of OPFRs. Development of new photocatalytic materials, in-depth study of the degradation mechanism of different catalysts and flame retardants, and attention to practical applications and toxicity issues can be the development direction of future research.

Persistence and pathway of glyphosate degradation in the coastal wetland soil of central Delaware.

Glyphosate is a globally dominant herbicide. Here, we studied the degradation and microbial response to glyphosate application in a wetland soil in central Delaware for controlling invasive species (Phragmites australis). We applied a two-step solid-phase extraction method using molecularly imprinted polymers designed for the separation and enrichment of glyphosate and aminomethylphosphonic acid (AMPA) from soils before their analysis by ultra-high-performance liquid chromatography (UHPLC) and Q Exactive Orbitrap mass spectrometry methods. Our results showed that approximately 90 % of glyphosate degraded over 100 d after application, with AMPA being a minor (<10 %) product. Analysis of glyphosate-specific microbial genes to identify microbial response and function revealed that the expression of the phnJ gene, which codes C-P lyase enzyme, was consistently dominant over the gox gene, which codes glyphosate oxidoreductase enzyme, after glyphosate application. Both gene and concentration data independently suggested that C-P bond cleavage-which forms sarcosine or glycine-was the dominant degradation pathway. This is significant because AMPA, a more toxic product, is reported to be the preferred pathway of glyphosate degradation in other soil and natural environments. The degradation through a safer pathway is encouraging for minimizing the detrimental impacts of glyphosate on the environment.

Visible light induced photocatalytic degradation of methylene blue using carbon fibre cloth - Bismuth oxybromide - Water hyacinth derived silver nanocomposite.

Methylene Blue (MB), a frequently used cationic dye, is recognized for its persistence and probable toxicity, making its removal from wastewater an urgent environmental concern. This study reports the solar photocatalytic degradation efficiency of MB by bismuth oxybromide-green silver nanoparticles (AgNPs) as catalyst. AgNPs were produced by the green synthesis method from an invasive aquatic weed water hyacinth (Pontederia crassipes). The AgNPs were doped on Bismuth oxybromide (BiOBr) nanosheets formed on the surface of carbon fibre cloth (CFC) to form the catalyst CFC-BiOBr-Ag. Under optimum conditions of 5 mg/L of initial MB concentration and near-neutral pH, one piece of CFC-BiOBr-Ag photocatalyst (5.78 mg/L) exhibited 95.68% degradation efficiency of MB in 4 h. TOC removal studies showed a removal efficiency of 74.82% after 4 h, indicating the potential for mineralization of MB. Adsorption-photocatalysis-desorption study revealed complete degradation of adsorbed MB at the end of the photocatalytic degradation. Additionally, the catalyst exhibited good reusability, with more than 84.88% degradation efficiency even after five cycles of use. Under direct sunlight, the CFC-BiOBr-Ag catalyst demonstrated MB degradation efficiency of 97.52% after 3 h of treatment. MB breakdown was evidently done by the hole (h+) and the superoxide radical (O2•-). The mechanism of MB degradation was adsorption and subsequent degradation by the CFC-BiOBr-Ag photocatalyst. The prevalent degradation reactions such as demethylation, ring opening, hydroxylation, •OH radicle attack, desulfonication, hydrolysis etc. led to formation of various intermediates which further mineralized to CO2 and H2O.

Genomic analysis and metabolic characteristics provide insights into inorganic nitrogen metabolism of novel bacterium Acinetobacter pittii J08.

A novel A. pittii J08 with heterotrophic nitrification and aerobic denitrification (HN-AD) isolated from pond sediments could rapidly degrade inorganic nitrogen (N) and total nitrogen (TN-N) with ammonium (NH4+-N) preference. N degradation rate of NH4+-N, nitrite (NO2--N) and nitrate (NO3--N) were 3.9 mgL-1h-1, 3.0 mgL-1h-1 and 2.7 mgL-1h-1, respectively. In addition, strain J08 could effectively utilize most of detected low-molecular-weight carbon (LMWC) sources to degrade inorganic N with a wide adaptability to various culture conditions. Whole genome sequencing (WGS) analysis revealed that assembled genome of stain J08 possessed the crucial genes involved in dissimilatory/assimilatory NO3--N reduction and NH4+-N assimilation. These results indicated that strain J08 could be applied to wastewater treatment in aquaculture.

Mapping Photogenerated Electron-Hole Behavior of Graphene Oxide: Insight into a New Mechanism of Photosensitive Pollutant Degradation.

The use of graphene oxide (GO) photogenerated electron-hole (e-h+) pairs to degrade pollutants is a novel green method for wastewater treatment. However, the interaction between photosensitive pollutants and a GO-light system remains unclear. In this work, the mechanism of degradation of photosensitive pollutant tetracycline (TC) promoted by GO photogenerated e-h+ pairs was studied. Our studies encompassed the determination of TC removal kinetics, analysis of active substances for TC degradation, identification of degradation products, and computational modeling. Clear evidence shows that a new reaction mechanism of enhanced adsorption and induced generation of reactive oxygen species (ROS) was involved. This mechanism was conducive to significantly enhanced TC removal. Kinetic studies showed a first-order behavior that can be well described by the Langmuir-Hinshelwood model. Radical scavenging experiments confirmed that 1O2, •O2-, and holes (h+) were the main active substances for TC degradation. Electron spin resonance analysis indicated that photoexcited TC molecules may transfer electrons to the conduction band of GO to induce the generation of additional ROS. A major transformation product (m/z 459) during TC degradation was identified with liquid chromatography-mass spectrometry. Density functional theory calculation indicated a stronger adsorption between TC and GO under photoirradiation. This mechanism of photo-enhanced adsorption and synergistic induced generation of ROS provides a new strategy for the removal of emerging pollutants in water. Overall, the new mechanism revealed in this work expands the knowledge of applying GO to wastewater treatment and is of great reference value for research in this field.

Optimizing intermittent micro-aeration as a strategy for enhancing aniline anaerobic biodegradation: kinetic, ecotoxicity, and microbial community dynamics analyses.

Groundwater and soil contamination by aromatic amines (AAs), used in the production of polymers, plastics, and pesticides, often results from improper waste disposal and accidental leaks. These compounds are resistant to anaerobic degradation; however, micro-aeration can enhance this process by promoting microbial interactions. In batch assays, anaerobic degradation of aniline (0.14 mM), a model AA, was tested under three micro-aeration conditions: T30, T15, and T10 (30, 15, and 10 min of micro-aeration every 2 h, respectively). Aniline degradation occurred in all conditions, producing both aerobic (catechol) and anaerobic (benzoic acid) byproducts. The main genera involved in T30 and T15 were Comamonas, Clostridium, Longilinea, Petrimonas, Phenylobacterium, Pseudoxanthomonas, and Thiobacillus. In contrast, in T10 were Pseudomonas, Delftia, Leucobacter, and Thermomonas. While T30 and T15 promoted microbial cooperation for anaerobic degradation and facultative respiration, T10 resulted in a competitive environment due to dominance and oxygen scarcity. Despite aniline degradation in 9.4 h under T10, this condition was toxic to Allium cepa seeds and exhibited cytogenotoxic effects. Therefore, T15 emerged as the optimal condition, effectively promoting anaerobic degradation without accumulating toxic byproducts. Intermittent micro-aeration emerges as a promising strategy for enhancing the anaerobic degradation of AA-contaminated effluents.

Elucidation of Degradation Behavior of Barbiturates in Artificial Gastric Juice: Study on Degradability of Drugs in Stomach (V).

The gastric stability of eight barbiturates (BARs) (barbital, primidone, allobarbital, phenobarbital, cyclobarbital, pentobarbital, secobarbital, and thiobutabarbital (TBB)) was examined in artificial gastric juice using LC/UV detection. Among the eight BARs, only TBB was degraded at higher temperatures. Furthermore, the degradation product of TBB was isolated, structurally analyzed, and finally identified as 5-butan-2-yl-5-ethyl-1,3-diazinane-2,4,6-trione, also known as butabarbital. The study elucidated that butabarbital was formed by substituting the sulfur atom of the carbonyl group at the 2-position of TBB with an oxygen atom under acidic condition.

Isolation and Identification of Naphthalene-Degrading Bacteria and its Application in a Two-phase Partitioning Bioreactor.

Naphthalene is a persistent environmental pollutant for its potential teratogenic, carcinogenic and mutagenic effects. In this study, 10 strains of bacteria capable of degrading naphthalene were isolated from crude-oil contaminated soil. Among them, Pseudomonas plecoglossicida 2P exhibited prominent growth with 1000 mg/L naphthalene as the sole carbon source and degraded 94.15% of naphthalene in 36 h. Whole genome sequencing analysis showed that P. plecoglossicida 2P had a total of 22 genes related to naphthalene degradation, of which 8 genes were related to the salicylic acid pathway only, 5 genes were related to the phthalic acid pathway only, 8 genes were common in both the salicylic acid and phthalic acid pathways, and 1 gene was related to the gentisic acid pathway. P. plecoglossicida 2P was applied in a two-phase partition bioreactor (TPPB) to degrade naphthalene in wastewater. The optimal operating conditions of the reactor were obtained through response surface optimization: initial naphthalene concentration (C0) =1600 mg/L, bacterial liquid concentration (OD600) = 1.3, and polymer-to-wastewater mass ratio (PWR) = 2%. Under these conditions, the naphthalene degradation rate was 98.36% at 24 h. The degradation kinetics were fitted using the Haldane equation with a high coefficient of determination (R2=0.94). The present study laid foundations for naphthalene degradation mechanism of genus Pseudomonas and its potential application in TPPB.

A Sustainable Approach for Degradation of Alternariol by Peroxidase Extracted from Soybean Hulls: Performance, Pathway, and Toxicity Evaluation.

Alternariol (AOH), an emerging mycotoxin, inevitably exists widely in various food and feed commodities with cereals and fruits being particularly susceptible, raising global concerns over its harm to human and livestock health. The development of eco-friendly and efficient strategies to decontaminate AOH has been an urgent task. This study provided insight into the utilization of crude soybean hull peroxidase as a powerful biocatalyst for degrading AOH. The results confirmed that crude soybean hull peroxidase (SHP) could catalyze the oxidation of AOH by use of H2O2 as a co-substrate. The optimum reaction conditions for SHP-catalyzed AOH degradation were recorded at pH 4.0-8.0, at 42-57 °C, and at H2O2 concentration of 100-500 µM. Mass analysis elucidated the degradation of AOH through hydroxylation and methylation by crude SHP. Moreover, toxicological analysis indicated that crude SHP-catalyzed AOH degradation detoxified the hepatotoxicity of this mycotoxin. The performance of crude SHP to degrade AOH in food matrices was further evaluated, and it was found that the enzyme agent could achieve AOH degradation by 77% in wheat flour, 84% in corn flour, 34% in grape juice, and 26% in apple juice. Collectively, these findings establish crude SHP as a promising candidate for effective AOH degradation, with potential applications in the food and feed industry.

Genome and metabolome analysis of Bacillus sp. Hex-HIT36: A newly screened functional microorganism for the degradation of 1-hexadecene in industrial wastewater.

1-Hexadecene has been detected at a level of mg/L in both influent and effluent of wastewater treatment plants situated in chemical/pharmaceutical industrial parks, which poses a potential threat to the environment. However, few reports are available on aerobic metabolic pathways and microorganisms involved in 1-Hexadecene degradation. In this study, a new strain of 1-Hexadecene-degrading bacteria, Bacillus sp. Hex-HIT36 (HIT36), was isolated from the activated sludge of a wastewater treatment plants located in an industrial park. The physicochemical properties and degradation efficacy of HIT36 were investigated. HIT36 was cultured on a medium containing 1-Hexadecene as a sole carbon source; it was found to remove ∼67% of total organic carbon as confirmed by mass spectrometric analysis of intermediate metabolites. Metabolomic and genomic analysis showed that HIT36 possesses various enzymes, namely, pyruvate dehydrogenase, dihydropolyhydroxyl dehydrogenase, and 2-oxoglutarate-2-oxoiron oxidoreductase (subunit alpha), which assist in the metabolization of readily available carbon source or long chain hydrocarbons present in the growth medium/vicinity. This suggests that HIT36 has efficient long-chain alkane degradation efficacy, and understanding the alkane degradation mechanism of this strain can help in developing technologies for the degradation of long-chain alkanes present in wastewater, thereby assisting in the bioremediation of environment.

Constructing Direct Z-Scheme Y2TmSbO7/GdYBiNbO7 Heterojunction Photocatalyst with Enhanced Photocatalytic Degradation of Acetochlor under Visible Light Irradiation.

This study presents a pioneering synthesis of a direct Z-scheme Y2TmSbO7/GdYBiNbO7 heterojunction photocatalyst (YGHP) using an ultrasound-assisted hydrothermal synthesis technique. Additionally, novel photocatalytic nanomaterials, namely Y2TmSbO7 and GdYBiNbO7, were fabricated via the hydrothermal fabrication technique. A comprehensive range of characterization techniques, including X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV-visible spectrophotometry, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray energy-dispersive spectroscopy, fluorescence spectroscopy, photocurrent testing, electrochemical impedance spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance, was employed to thoroughly investigate the morphological features, composition, chemical, optical, and photoelectric properties of the fabricated samples. The photocatalytic performance of YGHP was assessed in the degradation of the pesticide acetochlor (AC) and the mineralization of total organic carbon (TOC) under visible light exposure, demonstrating eximious removal efficiencies. Specifically, AC and TOC exhibited removal rates of 99.75% and 97.90%, respectively. Comparative analysis revealed that YGHP showcased significantly higher removal efficiencies for AC compared to the Y2TmSbO7, GdYBiNbO7, or N-doped TiO2 photocatalyst, with removal rates being 1.12 times, 1.21 times, or 3.07 times higher, respectively. Similarly, YGHP demonstrated substantially higher removal efficiencies for TOC than the aforementioned photocatalysts, with removal rates 1.15 times, 1.28 times, or 3.51 times higher, respectively. These improvements could be attributed to the Z-scheme charge transfer configuration, which preserved the preferable redox capacities of Y2TmSbO7 and GdYBiNbO7. Furthermore, the stability and durability of YGHP were confirmed, affirming its potential for practical applications. Trapping experiments and electron spin resonance analyses identified active species generated by YGHP, namely •OH, •O2-, and h+, allowing for comprehensive analysis of the degradation mechanisms and pathways of AC. Overall, this investigation advances the development of efficient Z-scheme heterostructural materials and provides valuable insights into formulating sustainable remediation strategies for combatting AC contamination.

Kinetics of Squalene Quenching Singlet Oxygen and the Thermal Degradation Products Identification.

Squalene has been proven to possess various bioactive functions that are widely present in vegetable oils. A more comprehensive understanding of the reaction behavior of squalene under oxidative conditions was achieved by studying its antioxidant capacity and thermal degradation products. The total singlet oxygen quenching rate constant (kr + kq) of squalene was 3.8 × 107 M-1 s-1, and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by ß-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.