Search Results (845)

Imidazolidin-2-thiones are versatile sulfur-containing heterocycles with broad biological relevance. The synthesis of (3aR,7aR)-1,3-bis(4-aminobenzyl)octahydro-2H-benzo[d]imidazole-2-thione (an imidazolidin-2-thione derivative) from trans-(R, R)-diaminocyclohexane is presented via a three-step sequence: formation of a Schiff base from 1,2-diamine and 4-nitrobenzaldehyde, followed by reduction with NaBH₄; thiocarbonylation under microwave irradiation (MW) to generate the imidazolidin-2-thione core; and reduction of the nitro substituents to amines using an iron/CaCl₂ system. The structure of the final compound was confirmed by detailed ¹H and ¹³C NMR analyses, demonstrating the preservation of the bicyclic backbone and the successful conversion of the nitro functional group. The overall yield of the sequence was 28%, with the reduction of the nitro group identified as the rate-limiting step. This protocol represents a viable synthetic strategy for obtaining functionalized imidazolidin-2-thiones useful for the development of novel bioactive sulfur-containing heterocycles. Full article

The microbes found in the rhizosphere, roots, leaves and stem surfaces and within the internal tissues of mangrove vegetation and their environment constitute the microbiome of the ecosystem. The organisms in the microbiome include bacteria, protozoa, fungi, algae, amoebas, and slime molds, which assist in maintaining and restoring mangrove ecosystems. This review explores the role of microbiomes in the maintenance of healthy mangrove ecosystems and in the successful restoration of degraded mangrove ecosystems. Microbes have important roles in several geomicrobiological cycles shaping mangrove ecosystems, including transforming nitrogen, phosphorus, carbon, sulfur and iron in biogeochemical cycles. Mangrove microbiomes contribute to the adaptation of vegetation to the harsh abiotic conditions in coastal areas, enhance nutrient uptake, produce plant-growth-promoting substances, and degrade the mangrove litter and the pollutants that can hinder restoration. Soil microbes function as biofertilizers, biopesticides, and bioremediation agents. The microbial diversity, composition, and functional capacity are important in the restoration of mangroves through their influence on voluntary recruitment following hydrologic restoration, on the establishment success of planted seeds and propagules, and on the survival of transplanted saplings and nursery-raised seedlings. The knowledge of the beneficial attributes of the microbiome can enhance the overall success of mangrove restoration. Identifying future needs, such as microbial inoculant validation, field-scale trials, and integration with hydrological restoration, are essential. Full article

In this study, polyhedral self-assembled spherical titania (TS) photocatalyst was successfully synthesized via a one-step hydrothermal method from titanium chloride, sodium dodecyl sulfate and sulfuric acid. Titania modification with iron was carried out through the same procedure by the addition of different amounts of iron(III) chloride to the substrate mixture. Various methods were applied for sample characterization, e.g., XRD, SEM, TEM, XPS, UV-vis DRS, and photo-electrochemical measurements, such as EIS, CV, transient photocurrent, whereas photocatalytic activity was investigated for hydrogen evolution under UV/vis and oxidative decomposition of antibiotics under UV and/or vis, including also tests with scavengers. It has been found that iron was both incorporated in the titania structure (doping) and adsorbed on its surface. Although iron presence has hardly influenced the properties (slight changes in morphology, bandgap energy, and crystallite size), the photocatalytic activity has increased significantly. Therefore, it is proposed that iron might work as an electron sink, hindering the charge carriers’ recombination. Linear evolution of hydrogen, recycling experiments and characterization of samples after recycling have confirmed a good stability of iron-modified titania. Full article

Hydrometallurgical leaching processes contain complex and nonlinear parameter interactions that are difficult to capture with conventional empirical models. In this study, a multiple hybrid machine learning approach was developed to predict manganese (Mn) and iron (Fe) dissolution efficiency in leaching systems and performed using sulfuric acid (H₂SO₄), hydrochloric acid (HCl), and nitric acid (HNO₃). A large-format dataset consisting of 204 independent leaching experiments was generated in which acid type, acid concentration (0.5–5 M), temperature (25–90 °C), solid/liquid ratio (100–200 g/L), leaching time (1–4 h), and eight different reducing agent types were systematically varied. XGBoost, LightGBM, CatBoost, and Random Forest algorithms were individually trained and subsequently combined with a Soft Voting Ensemble architecture. Hyperparameters were optimized using the RandomizedSearchCV method with 3-fold cross-validation. The XGBoost model achieved the highest prediction accuracy for Mn dissolution (R² = 0.8993, RMSE = 8.06%), while CatBoost demonstrated the best performance in Fe dissolution (R² = 0.8415, RMSE = 4.43%). SHAP analysis suggested that the dosage and type of reducing agents are the most influential predictive features for Mn dissolution, while acid molarity and temperature were identified as the dominant predictors for Fe leaching. Friedman test confirmed that performance differences among both Mn and Fe models were statistically significant (Mn: χ² = 32.76, p < 0.001; Fe: χ² = 25.96, p < 0.001). The developed models contribute significantly to hydrometallurgical process optimization by predicting the nonlinear effects of leaching parameters on metal dissolution with high accuracy. This study presents a comprehensive and interpretable machine learning framework supported by an extensive experimental dataset, a substantial portion of which has not been previously utilized or comparatively analyzed within a unified multi-acid framework, enabling systematic modeling of selective Mn–Fe dissolution across multiple acid systems and reducing agents. Full article

The identification of the chemical species responsible for the anomalous near-ultraviolet (UV) opacity in the Venusian cloud for “unknown absorber” remains a paramount challenge in planetary science. This study presents a comprehensive quantum chemical investigation into a broad suite of candidate molecules, including isomers of thiosulfeno (S₂O₂), the hydroxysulfonyl radical (HSO₃), disulfur monoxide (S₂O), disulfur dichloride (S₂Cl₂), iron(III) chloride (FeCl₃), phosphine (PH₃), and structural isomers of polysulfur oxides (S₃O). Utilizing Time-Dependent Density Functional Theory (TD-DFT) at the CAM-B3LYP/def2-TZVPP level of theory, we systematically mapped electronic transitions across three distinct environmental phases: gas-phase (without solvent), supercritical CO₂, and concentrated H₂SO₄ aerosols. To establish confidence in the predicted results, our TD-DFT approach was rigorously benchmarked against high-level theoretical methods (CCSD(T), EOM-CCSD, and MRCI+Q) from recent literature. All these electronic transitions were modeled via the Solvation Model based on Density (SMD). Our results demonstrate a profound topological and environmental dependence on spectral signatures. Among the candidates, trans-OSSO (t-OSSO) emerged as the most viable near-UV absorber candidate, exhibiting a highly allowed π → π* transition at 379.37 nm (f = 0.1140) in H₂SO₄, providing a near-perfect alignment with the observed 365 nm planetary albedo drop. Conversely, the polysulfur oxide cis-S₃O was acknowledged as a primary visible-light chromophore, with an intense absorption at 436.31 nm (f = 0.1280) responsible for the characteristic yellow tint of the planet. Additionally, the photochemically maintained SSCl₂ isomer was identified as a critical broadband near-UV absorber. Species such as S₂O and planar S₃O were found to function as critical mid-UV shields (270–300 nm). This work establishes a multi-chromophore model of the Venusian atmosphere, where a chemically stratified network of sulfur-oxygen chains and chlorine-sulfur reservoirs, tuned by the acidic aerosol matrix, collectively governs radiative balance and atmospheric super-rotation of the planet. Furthermore, to account for massive continuum tailing into the visible region (>400 nm), we employed a semi-classical Reflection Principle approach to model 1D vibronic broadening. This analysis revealed that while standard solvent effects induce minor solvatochromic shifts, ground-state structural fluxionality in the OSSO isomers drives intense, symmetry-allowed transitions deep into the visible spectrum, an effect absent in structurally constrained or rigid control species. Full article

Iron-exchanged bentonites derived from a natural montmorillonite-rich clay (Taganskoe deposit, Kazakhstan) were prepared through a simple aqueous ion-exchange route using Fe(II) or Fe(III) inorganic salt precursors, yielding final Fe contents of ca. 5–7 wt.%, while preserving the smectite layered framework. A mild thermal treatment under air was applied to tune iron coordination without triggering major structural collapse. The resulting materials were characterized by ED-XRF, PXRD, FE-SEM/EDX, DLS/ζ-potential and DR UV–Vis–NIR spectroscopy, revealing predominantly exchanged Fe species with a limited fraction of surface iron-oxide clusters, whose contribution increases after activation. Structure–reactivity relationships were probed under mild conditions in liquid-phase ethyl acetate using dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethyl sulfide (2-CEES) as organophosphorus and organosulfur hazardous chemicals and chemical warfare agent simulants, respectively. Fe(III)-bentonite enabled very fast DMMP removal (ca. 93% within 0.5 h) with a remarkable improved performance with respect to Fe(II)-bentonite and the pristine mineral clay. For 2-CEES, the presence of H₂O₂ markedly enhanced oxidation on Fe-containing clays, reaching quantitative abatement within 24 h (up to >90%), with strong retention of oxidized sulfur products by the clay matrix. These results highlight Fe-exchanged natural bentonites as robust, cheap and multifunctional adsorption/catalytic solids for decontamination and water-treatment applications. Full article

Direct Coal Liquefaction (DCL) is a promising route for converting abundant coal resources into liquid fuels, yet its efficiency remains strongly dependent on catalyst performance. In this work, we present an integrated computational framework combining density functional theory (DFT) calculations with machine learning (ML) to investigate iron–sulfur (FeS) cluster catalysts for DCL. DFT calculations were employed to examine hydrogen-donor dissociation and coal-derived radical hydrogenation on representative FeS clusters. The results indicate that the most favorable catalytic pathways arise from the cooperation between metallic Fe sites (Fe_2) and interfacial Fe sites adjacent to sulfur (Fe_1), while sulfur atoms mainly play an indirect structural and electronic modulation role. Based on these mechanistic insights, a database containing thermodynamic and kinetic data for 636 reactions across 50 FeS cluster models was constructed. This dataset was then used to train three ML classifiers, among which the Random Forest model showed the best performance, reaching accuracies of 80% for H-donor cleavage and 93% for radical hydrogenation on the held-out test sets. SHapley Additive exPlanations (SHAP) analysis further showed that descriptors associated with Fe active-site identity were among the most influential variables in both tasks. Overall, this work provides a mechanistically informed and interpretable computational framework for understanding FeS-catalyzed DCL chemistry and for the preliminary screening of catalyst motifs within the chemical space covered by the present FeS cluster library. Full article

Heavy metal pollution remains a major global environmental challenge due to persistent ecological risks and potential threats to food safety. Microbial remediation and phytoremediation represent sustainable alternatives to conventional treatments; however, their effectiveness is strongly influenced by number of factors including nutrient availability. This review critically examines how nutritional regulation governs microbial metabolism, plant physiological responses, and rhizosphere interactions to enhance heavy metal transformation and removal. Metal bioavailability depends on type, concentration, soil pH, redox potential, and microbial processes. Interventions including fertilizers, chelating agents, inoculation with arbuscular mycorrhizal fungi and plant-growth-promoting rhizobacteria enhance phytoremediation processes through regulating plant nutrient and heavy metal uptake, while selection between ammonium/nitrate changes rhizosphere pH consequently affects plant metal uptake. Similarly, nutrients, i.e., phosphate, iron, zinc and manganese competitively affect metal uptake. Organic amendments enhance phytostabilization, especially for selenium and mercury, while enhancing chromium reduction. Sulfur-reducing bacteria precipitate metals as insoluble sulfides with 90% efficiency. In addition, soil amendments including plant-growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and metal-chelating agents can be strategically used to enhance the phytoextraction from metal from contaminated soils. We suggest that the future integration of modern approaches such as multi-omics and cisgenesis supported by artificial intelligence tools can help to accurately predict the efficiency of nutrient regulation strategies and their remediation outcomes, thereby supporting evidence-based soil management. Full article

This article presents the results of developing a hydrometallurgical method for processing polymetallic sublimates containing arsenic, zinc, copper, and lead. Using sublimates from “BalkhashPolymetal” LLP (Kazakhstan) as an example, the optimal conditions for sulfuric acid leaching were determined as follows: t = 80–85 °C, H₂SO₄ = 25 g/dm³, τ = 60 min. Under these conditions, extraction of arsenic was 93%, zinc 80%, and copper 42% was achieved. Iron(II) hydroxide was used to remove arsenic from the solution, which made it possible to reduce the residual As content in the solution to 0.02 g/L and return approximately 97% of copper to the process cycle. Eh–pH analysis of the Fe–As–Cu–H₂O system confirmed the thermodynamic stability of Fe(II/III) arsenates in the selected pH range 3–5. The obtained results can be used to develop safe and resource-saving technologies for processing technogenic raw materials. Full article

In the present study, a kinetic model was developed for the process of oxidative desulfurization of light gas oil with 7329 ppm sulfur using a newly synthesized nanocomposite catalyst. The batch reactor experiments were conducted at different thermal conditions (313–373 K) and reaction times (30–90 min) to explain this endeavor of desulfurization performance as a function of these variables, targeting the design of a reliable reactor system. Carbon nanofibers (CNFs) were integrated into the support γ-Al₂O₃ at various concentrations of 5%, 7.5%, and 10% to improve mechanical properties, surface area, and distribution of active metals. The nanocomposite support was impregnated with molybdenum trioxide (MoO₃) and iron oxide (Fe₂O₃) to form four variants of the catalyst: CAT-1 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 5% CNF, CAT-2 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 7.5% CNF, CAT-3 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 10% CNF, and CAT-4 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ with no CNF. CAT-3 had the best effectiveness for sulfur removal with 87.5% at 373 K and a reaction time of 90 min. The model predicts a maximum sulfur removal rate of 99.86% under optimal conditions of 550 K and 200 min (for an initial sulfur concentration of 7329 ppm). The experimental and modeling results therefore indicate the potential of the developed catalyst system, while the optimum condition at 550 K and 200 min should be interpreted as a model-predicted outcome. The development of such highly efficient nanocatalysts for deep desulfurization is a crucial advancement in green chemistry, directly contributing to the production of cleaner fuels to mitigate air pollution and supporting the aims of the United Nations Sustainable Development Goals (SDGs), particularly SDG 9 (Industry, Innovation, and Infrastructure) and SDG 12 (Responsible Consumption and Production). From a sustainability perspective, the proposed ODS system supports cleaner fuel production and reduced sulfur-derived emissions, while operating-condition optimization helps improve process efficiency in support of more sustainable refining strategies. Full article

Radionuclide contamination of surface water bodies poses a significant environmental challenge, particularly for low-productivity dystrophic systems where natural self-purification capacity is limited. This study aimed to assess the potential of phytoplankton and bottom sediments as biogeochemical barriers for radionuclides. Laboratory modeling of ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am accumulation was conducted using samples of Lake Dryazlo (Tver Oblast) water and bottom sediments as a representative dystrophic model system. Sorption onto phytoplankton biomass over a single growing season was estimated at 1.89 × 10⁴, 5.41 × 10⁴, 6.64 × 10⁴, and 4.04 × 10⁴ Bq g⁻¹ dry biomass for ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am, respectively. Actinide immobilization in bottom sediments depended on mineral composition and microbial community activity. Ammophos addition increased radionuclide removal from the liquid phase by 2–5-fold through enhanced phytoplankton productivity, and promoted actinide fixation via phosphate mineral phase formation and stimulation of anaerobic sulfur- and iron-cycling bacteria. These results demonstrate a viable biogeochemical barrier approach applicable to the decommissioning of radioactive waste storage ponds and remediation of radionuclide-contaminated water bodies. Full article

Bortezomib (BTZ), the first-generation proteasome inhibitor, has been approved for the treatment of relapsed, refractory, and newly diagnosed multiple myeloma. Despite its remarkable antitumor efficacy, BTZ treatment is severely limited by a high incidence of systemic adverse reactions, primarily due to its non-selective cytotoxicity toward rapidly dividing normal cells and its potent neurotoxic effects on peripheral neurons. Bortezomib-induced peripheral neurotoxicity (BIPN) manifests as neuropathic pain and sensory abnormalities, affecting up to 31% to 64% of patients and limiting BTZ’s clinical use. Currently, the underlying mechanisms of BIPN are poorly understood. To evaluate the effects of BTZ on the functions of peripheral nerves in mice, we administered an intraperitoneal injection treatment for four weeks. Results indicated that BIPN caused mechanical allodynia, gait abnormalities, and pathological changes in myelin and axons in mice. This study confirms that BTZ upregulates the expression of the activating transcription factor 3 (ATF3), which in turn mediates the increased expression of the copper transporter SLC31A1, causing dysregulation of intracellular copper ion homeostasis and subsequent copper accumulation, and ultimately inducing the development of peripheral neurotoxicity. Elevated intracellular copper concentration exerts a dual effect: it directly promotes the oligomerization of Dihydrolipoamide S-acetyltransferase (DLAT) and concurrently damages the iron–sulfur cluster protein ferredoxin 1 (FDX1), collectively triggering the onset of cuproptosis. Green tea has garnered attention for its rich content of catechins, with (−)-Epigallocatechin Gallate (EGCG) being the most abundant catechin present. This study uncovers the molecular mechanism by which EGCG inhibits BTZ-induced cuproptosis through targeted regulation of copper homeostasis. Analyses demonstrate that EGCG significantly downregulates the expression of the copper transporter SLC31A1, thereby effectively suppressing transmembrane influx of extracellular copper ions. This intervention markedly reduces intracellular copper overload, eliciting a dual regulatory effect: on one hand, the decreased copper concentration directly inhibits the oligomerization of DLAT; on the other hand, it effectively protects the iron–sulfur cluster protein FDX1 from damage. This study aims to systematically elucidate the molecular mechanisms underlying BIPN and to evaluate the therapeutic potential of EGCG in alleviating BIPN, offering a novel therapeutic strategy for the prevention and treatment of BIPN. Full article

Rivers contaminated with metals and petroleum hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), are still a problem that threatens aquatic ecosystem function. This study describes iron- and sulfate-reducing bacteria, principal drivers of anaerobic organic matter decomposition in aquatic sediments. A polyphasic approach, including culture-dependent, i.e., enumeration by Most Probable Number (MPN), and independent, Sanger and Next Generation Sequencing (NGS) techniques, as well as analytical geochemical analyses, was employed. This study found exceptionally high levels of metals (Al, Mn, Zn, and Pb), PAHs, and sulfates compared to typical freshwater environments, likely due to co-contamination from past petroleum and steel production waste. Microbial communities were dominated by the Thermoproteobacteria. Analysis of the iron-reducing community determined that Geobacter, critical for degrading organic matter using iron, manganese, or arsenic, was the most prevalent genus. Additionally, the presence of diverse groups involved in sulfur cycling, represented by dsrAB genes, high numbers of viable sulfate reducers, a higher abundance of Geobacter, and high levels of sulfate and iron suggests that the cryptic sulfur cycle (CSC) may be operational in this system. In addition, sulfate and iron reducers are known to enhance biodegradation of organic pollutants in the presence of metal oxides and sulfate, and thus warrant further investigation in this co-contaminated system. Full article

Mangroves are widely recognized as climate-relevant ecosystems, yet the extent to which soils are incorporated into climate mitigation research remains unclear. This study conducted a hierarchical bibliometric analysis (Scopus, 1950–2025) across five progressively restrictive search levels, moving from general mangrove research (Level 1) to studies incorporating climate change (Level 2), mitigation (Level 3), and soil-related processes (Levels 4 and 5). Results show that although 30,084 articles addressed mangrove broadly, only 25 articles (0.08%) explicitly linked mangrove soils to climate change mitigation, with the majority published after the emergence of the blue carbon concept in 2009. Keyword evolution and network analyses indicate a shift from descriptive ecological themes (e.g., distribution and vegetation dynamics) toward carbon-related and soil-associated processes (e.g., blue carbon, carbon sequestration, soil organic carbon), particularly after the late 2000s, accompanied by gradual diversification into Environmental Science, Earth and Planetary Sciences, and chemistry-related domains associated with soil processes and mitigation mechanisms. Despite these conceptual advances, keyword analysis shows that mitigation-related studies (Levels 3 and 5) remain largely focused on terms such as “mangroves” (336 occurrences), “carbon sequestration” (187), “organic carbon” (82), and “carbon storage” (62), with limited representation of mechanistic soil processes (e.g., redox-processes, soil greenhouse gas fluxes, carbon–iron–sulfur coupled dynamic) in climate mitigation frameworks. Expanding this integration represents a key scientific frontier for improving the robustness and scalability of mangrove-based climate mitigation strategies. Full article

In this work, three sulfur-iron materials (sulfide-modified nanoscale zerovalent iron (S-nZVI), ferrous sulfide (FeS), and pyrite (FeS₂)) were employed to enhance the Fenton process for naphthalene (NAP) degradation. The enhancement performance and mechanisms of S-nZVI, FeS, and FeS₂ were investigated and compared. The results showed that NAP removal was enhanced from 56.4% in the H₂O₂/Fe(II) system to 88.6%, 83.0%, and 89.1% with the addition of S-nZVI, FeS, and FeS₂, respectively. Three sulfur-iron materials could all reduce Fe(III) produced in aqueous solution, regenerate Fe(II), and slow down the precipitation of dissolved iron. In addition, the addition of sulfur-iron materials could promote the generation of hydroxyl radical (HO•), thus intensifying the degradation of NAP. The results of scavenging tests indicated that HO• was the dominant reactive oxygen species (ROS) for NAP removal, while superoxide radical (O₂⁻•) also participated. The effect of complex water matrices on NAP degradation was evaluated, showing that sulfur-iron material-enhanced techniques had a wide pH application range and had great tolerance to inorganic ions and humic acid. Moreover, NAP degradation intermediates and their toxicity were elucidated. Finally, the obvious removal of various pollutants in sulfur-iron material-enhanced systems demonstrated that these technologies could be used to remediate organic-polluted groundwater. Full article