Search Results (1,080)

This study explores the application of a cobalt–manganese oxide catalyst supported on coal gangue (CoMnOx@CG) for peroxymonosulfate (PMS) activation to degrade phenol in coal chemical wastewater (CCW). The synthesized CoMnOx@CG catalyst demonstrated remarkable catalytic activity, achieving above 90% phenol removal within 10 min at pH 9 and 11. More importantly, the catalyst exhibited excellent stability and reusability, maintaining over 85% phenol removal efficiency after four consecutive cycles and cobalt leaching below 100 μg/L. Quenching experiments and electron paramagnetic resonance (EPR) analyses revealed that singlet oxygen (¹O₂), sulfate radicals (SO₄·⁻), and hydroxyl radicals (·OH) contributed to the degradation process. When treating actual CCW, the system significantly reduced both phenol and fluorescent dissolved organic matter, demonstrating its effectiveness for complex wastewater matrices. CoMnOx@CG provides a sustainable and practical solution for alkaline refractory wastewater remediation. Full article

Growing environmental concern over pharmaceutical contaminants in water, combined with the limited effectiveness of conventional treatment methods in removing persistent antibiotics, creates a need for advanced remediation technologies. This study investigates the degradation of the cephalosporin antibiotic cefuroxime axetil using an electrochemical advanced oxidation process with a boron-doped diamond (BDD) anode. Experiments were conducted under varying pH levels and in natural water matrices, specifically river and lake water, to evaluate the process efficiency under realistic conditions. Significant differences were observed between matrices, with the best result obtained in river water, enabling complete degradation of cefuroxime axetil within 30 min. To clarify the factors influencing process efficiency, additional experiments examined the effects of dissolved organic matter (DOM) and chlorides. Cefuroxime axetil proved highly susceptible to electrooxidation, generally following pseudo-first-order kinetics, and chloride significantly accelerated its degradation. Using high-resolution mass spectrometry, ten transformation products were identified, including six not previously reported in the literature, representing a key novelty of this work. Their potential aquatic toxicity was subsequently evaluated in silico using fish and algae models. Finally, energy consumption analysis was conducted to evaluate the impact of various factors on the process’s economic efficiency. Full article

This study investigates the impact of tire wear particles (TWPs) and their dissolved organic matter (DOM) on soil DOM dynamics and heavy metal behavior. Through short-term incubation experiments under simulated natural conditions with TWPs of varying particle sizes, we analyzed ecological changes in soil. Using three-dimensional excitation–emission matrix (3D-EEM) spectroscopy coupled with parallel factor analysis, we monitored the photochemical properties and compositional evolution of soil dissolved organic matter. Results demonstrate that TWP amendment substantially alters soil DOM molecular characteristics, inducing a sharp decrease in protein-, carbohydrate-, and lipid-like components, the degradation of low-aromaticity unstable dissolved organic matter, and an overall increase in aromaticity. Furthermore, TWP input directly modified soil properties, triggering the transformation of soil aggregates: the proportion of large aggregates significantly decreased while that of small aggregates increased, thereby reducing overall aggregate stability. The bioaccessibility of heavy metals (HMs) (Cd, Cu, and Zn) extracted by CaCl₂ increased, primarily due to the release of endogenous metals from TWPs, compounded by the disruption of soil aggregates. In contrast, Pb tended to transform into more stable fractions under TWP stress, reducing its bioaccessibility. Further correlation analysis indicated that TWPs indirectly affected HM (Cd, Cu, and Zn) fractionation by influencing the soil dissolved organic matter properties and soil properties. This study provides a new perspective for elucidating the interplay between dissolved organic matter and HMs in urban soils, as mediated by tire wear particles (TWPs). Full article

During the 71st cruise of the R/V Akademik Oparin in the summer of 2024, we assessed the distributions of dissolved and particulate forms of ²¹⁰Pb and ²¹⁰Po in the Sea of Japan, the Sea of Okhotsk, and the northwestern Pacific Ocean. Quantitative estimates of vertical fluxes were derived based on measured concentrations of suspended particulate matter (SPM) and particulate organic carbon (POC). This study provides the first in situ measurements of these radionuclides and the first estimates of derived fluxes for the Sea of Okhotsk. The study confirmed the existence of two contrasting biogeochemical regimes: a sedimentation regime in the productive waters of the Sea of Okhotsk and a recycling regime in the oligotrophic waters of the open ocean, separated by the dynamic transition zone of the Kuril Islands. The calculated POC fluxes confirmed the high efficiency of the biological pump in the coastal seas. The identified anomalies in the distribution of radionuclides indicate a significant role of lateral transport and the sorption of organic carbon onto mineral particles in shaping vertical fluxes matter. Full article

This study evaluated how different additives—Lactiplantibacillus plantarum (LP), Lentilactobacillus buchneri (LB), and a composite enzyme (CE)—affect the fermentation quality, nutritional value, and microbial community of Leymus chinensis silage. Fresh forage was wilted to 65% moisture, treated with additives (dissolved in distilled water), and vacuum-sealed in polyethylene bags for 60 days of ensiling. Fermentation parameters and nutritional composition were analyzed using standard methods (e.g., HPLC for organic acids, Kjeldahl for crude protein), and the microbial community was profiled via Illumina MiSeq sequencing of the 16S rRNA gene V3-V4 region. Data were subjected to one-way ANOVA and Duncan’s test in SAS. All additives significantly improved key fermentation parameters (p < 0.05). The LP treatment yielded the most favorable profile, with the lowest pH (4.26) and the highest lactic acid (6.52 g/kg DM) and acetic acid (2.58 g/kg DM) contents. LP also best preserved nutrients, showing the highest dry matter (581.62 g/kg FW), water-soluble carbohydrates (24.76% g/kg DM), and crude protein (7.09% DM) (p < 0.05). The CE treatment most effectively degraded fiber, resulting in the lowest acid detergent fiber (428.87% g/kg DM) and neutral detergent fiber (628.43% g/kg DM) (p < 0.05). Additives significantly reduced bacterial alpha-diversity but enriched beneficial phylum such as Bacillota and genus such as Lentilactobacillus spp. LB), while suppressing harmful genera. Correlation analysis confirmed LP was positively correlated with lactic acid and water-soluble carbohydrates (p < 0.0001). In conclusion, additives, particularly LP, enhance silage quality by modulating the microbial community. Full article

This study uses high-frequency monitoring across a river–barrier lake–reservoir continuum in the upper Minjiang River, southwestern China, to quantify the spatiotemporal dynamics and drivers of aquatic CO₂ partial pressure (pCO₂) and to identify the dominant controls under contrasting lotic and lentic conditions. River reaches were CO₂-supersaturated throughout the year, with higher pCO₂ in the wet season (mean 521 ppm) than in the dry season (421 ppm), indicating persistent CO₂ evasion to the atmosphere. In contrast, the downstream canyon-type reservoir showed a pronounced seasonal reversal. During the wet season, surface-water pCO₂ averaged 395 ppm, about 24% lower than that of the river and below atmospheric levels (~419 ppm); more than 55% of observations were undersaturated, with minima as low as 141–185 ppm, indicating temporary CO₂-sink behavior. In the dry season, mean pCO₂ increased to 563 ppm, exceeding both riverine and atmospheric levels and returning the reservoir to a CO₂ source. The reservoir pCO₂ variability was governed by the interaction of hydrology and metabolism: rising water levels and longer residence times likely enhanced CO₂ accumulation from the decomposition of inundated organic matter, while warm temperatures, high light and monsoon-driven nutrient inputs promoted phytoplankton growth that removed dissolved CO₂ and elevated dissolved oxygen, producing temporary sink behavior. In the river, short residence time and strong turbulence limited in-stream biological regulation, and pCO₂ variability was mainly driven by catchment-scale carbon inputs along the elevation gradient. Overall, our results demonstrate that dam construction and impoundment can substantially modify carbon cycling in high-mountain rivers. Under specific conditions (warm water, sufficient nutrients, high algal biomass), lentic environments may strengthen photosynthetic CO₂ uptake and temporarily transform typical riverine CO₂ sources into sinks, with important implications for carbon-budget assessments and reservoir management in mountainous basins. Full article

Real-time monitoring is essential for maintaining water quality and optimizing aquaculture productivity. Ion-selective electrodes (ISEs) are widely used to measure key parameters such as pH, nitrate, and dissolved oxygen in aquatic environments. However, these sensors are prone to fouling, the non-specific adsorption of organic, inorganic, and biological matter, which leads to potential drift (e.g., 1–10 mV/h), loss of sensitivity (e.g., ~40% in 20 days), and reduced lifespan (e.g., 3 months), depending on membrane formulation and environmental conditions. This review summarizes current research from mostly the last two decades with around 150 scientific studies on fouling phenomena affecting ISEs, as well as recent advances in fouling detection, cleaning, and antifouling strategies. Detection methods range from electrochemical approaches such as potentiometry and impedance spectroscopy to biochemical, chemical, and spectroscopic techniques. Regeneration and antifouling strategies combine mechanical, chemical, and material-based approaches to mitigate fouling and extend sensor longevity. Special emphasis is placed on environmentally safe antifouling coatings and material innovations applicable to long-term monitoring in aquaculture systems. The combination of complementary antifouling measures is key to achieving accurate, stable, and sustainable ISE performance in complex water matrices. Full article

Oil and grease (O&G) pollution in municipal effluents represents a critical environmental challenge. This study contributes a novel experimental assessment of how pressure and recirculation time influence oxygen transfer, microbubble generation, and pollutant removal in a pilot-scale DAF system, providing new insights into process optimization for municipal wastewater treatment. This study evaluated the efficiency of a DAF system in removing organic pollutants and solids from municipal effluent by varying gauge pressure (1–5 bar) and recirculation time (1–20 min). The initial concentrations present in the effluent were 800 mg/L total solids (TS), 590 mg/L total suspended solids (TSS), 450 mg/L oil and grease (O&G), 360 mg/L biochemical oxygen demand (BOD₅), and 710 mg/L chemical oxygen demand (COD). The concentration of dissolved air (interpreted as dissolved oxygen supersaturation) reached 102.3 mg/L and removal efficiencies of 84.4% for O&G, 88.9% for BOD₅, 88.7% for COD, and 85% for TSS were achieved, while pH and dissolved solids (DS) remained stable. The saturation factor (f = 0.8) confirmed efficient oxygen-liquid transfer, attributed to the use of Raschig rings in the absorption column. The significance of this work lies in demonstrating that operating conditions directly enhance oxygen dissolution and flotation performance, highlighting an optimization pathway rarely reported for municipal effluents. The results demonstrate that DAF is a robust, stable, and energy-efficient technology capable of effectively removing organic and lipid loads from municipal effluent, providing a sustainable alternative for the pretreatment and reuse of urban wastewater. Full article

Continuous cropping affects soil health, microbial diversity, and organic matter dynamics, but its long-term impacts on soils under Aralia continentalis Kitag. (a medicinally important Northeast China-native plant) remain unclear. This study evaluated effects of 2-, 6-, and 12-year continuous cropping on soil microbial communities, physicochemical properties, and dissolved organic matter (DOM) of bulk soils, and elucidated links between cropping duration and soil health indicators. Results showed that key physicochemical properties (total organic carbon, TOC) and available nutrients (available nitrogen, AN; available phosphorus, AP; available potassium, AK) declined with cropping duration: AN, AP, and AK decreased from 75.24 ± 1.2, 16.39 ± 0.05, and 104.8 ± 0.27 mg·kg⁻¹ (2 years) to 63.47 ± 1.53, 13.38 ± 0.16, and 88.71 ± 0.94 mg·kg⁻¹ (12 years), respectively. Microbial diversity increased initially but stabilized after 6 years, with communities shifting from copiotrophic taxa (e.g., Proteobacteria) to oligotrophic taxa (e.g., Acidobacteria). Partial Least Squares Path Modeling (PLS-PM) revealed strong positive correlations between dissolved/organic carbon (DOC/TOC) and microbial diversity, highlighting organic matter’s role in sustaining microbial richness. UV-visible and 3D fluorescence spectroscopy indices correlated significantly with microbial diversity, confirming their utility for monitoring DOM quality and microbial dynamics. This study clarifies dynamic interactions between soil properties, microbial diversity, and organic matter under continuous cropping, providing insights for sustainable cultivation of A. continentalis. Full article

Wastewater-derived microplastics (WW-MPs) are increasingly recognised as reactive vectors for aromatic organic contaminants (AOCs), yet their role in contaminant fate remains insufficiently constrained. This review synthesises current knowledge on the transformation of microplastics in wastewater treatment plants, including fragmentation, oxidative ageing, additive leaching, and biofilm formation, and links these processes to changes in sorption capacity toward phenols, PAHs and their derivatives, and organochlorine pesticides (OCPs). We summarise the dominant adsorption mechanisms-hydrophobic partitioning, π-π interactions, hydrogen bonding, and electrostatic and, in some cases, halogen bonding-and critically evaluate how wastewater-relevant parameters (pH, ionic strength, dissolved organic matter, temperature, and biofilms) can modulate these interactions. Evidence in the literature consistently shows that ageing and biofouling enhance WW-MP affinity for many AOCs, reinforcing their function as mobile carriers. However, major gaps persist, including limited data on real wastewater-aged MPs, lack of methodological standardisation, and incomplete representation of ageing, competitive sorption, and non-equilibrium diffusion in existing isotherm and kinetic models. We propose key descriptors that should be incorporated into future sorption and fate frameworks and discuss how WW-MP-AOC interactions may influence ecological exposure, bioavailability, and risk assessment. This critical analysis supports more realistic predictions of AOC behaviour in wastewater environments. Full article

Microplastics (MPs) and nanoplastics (NPs) are emerging aquatic contaminants that pose environmental and public health risks due to their persistence, ubiquity, and ability to adsorb co-contaminants. This scoping review synthesises findings from 57 experimental studies and five review studies published between 2019 and 2025 on the use of biochar-based materials for the removal of microplastics from water and wastewater. Guided by the hypothesis that surface-modified biochars, such as magnetised, surfactant-coated, or chemically activated forms, achieve high removal efficiencies through multimodal mechanisms (e.g., electrostatic attraction, hydrophobic interactions, π–π stacking, and physical entrapment), this review applies PRISMA-based protocols to systematically evaluate biochar feedstocks, pyrolysis conditions, surface modifications, polymer types, removal mechanisms, and regeneration approaches. Scopus, Web of Science, and PubMed were searched until 30 May 2025 (English-only), and 62 studies were included. The review was not registered, and no protocol was prepared. The results confirm a high removal efficiency (>90%) in most experimental studies, particularly under controlled laboratory conditions and using pristine polystyrene. However, the performance declines significantly in complex matrices (e.g., wastewater and surface water) owing to dissolved organic matter, ionic competition, and particle heterogeneity, thus supporting the guiding hypothesis. This review also identifies critical methodological gaps, including narrow plastic typologies, a lack of standardised testing protocols, and limited field-scale validation. Addressing these gaps through environmentally realistic testing, regeneration optimisation, and harmonised methods is essential for transitioning biochar from a promising sorbent to a practical water treatment solution. Full article

In July–August 2024, a severe dystrophic process occurred in the Orbetello lagoon (Italy). This study reports the following: (1) the macroalgal biomass and the sediment labile organic matter (LOM) between 2018 and 2024; (2) the water temperature and dissolved oxygen values between June and September 2024 and the T-mean, T-max, and T-min in July and August between 2013 and 2024; (3) the list of microphyte taxa that occurred during the dystrophy; (4) satellite images documenting the evolution of the dystrophic process. The results suggest that the dystrophy was caused by the decay of a large macroalgal mass and high accumulations of LOM in the sediment, which triggered anaerobic processes, particularly intense sulphate-reductive activity. This virulent process was facilitated by a record increase in temperatures (with T-min and T-max higher than those of the previous years), in a context of poor hydrodynamics, typical of non-tidal lagoons. Microphyte blooms, which occurred during the dystrophy, were at the basis of the evolution of the phenomenon, allowing for the most critical phase to be overcome through intense oxygen production. Microphytic blooms, with intense water colouring, although constituting an evident sign of a eutrophic/hypertrophic state of the lagoon, could lead to a rapid evolution of the dystrophy and mitigate the environmental conditions. Full article

Dissolved organic matter (DOM) is a crucial carbon source for soil microorganisms and plays a vital role in nutrient cycling and carbon (C) sequestration in soils. However, the extent to which soil microbes mediate DOM transformation at the molecular level, and whether this is regulated by different organic fertilization, remains unclear. Here, we designed a field experiment to investigate the transformations of DOM under three types of organic fertilization (straw, biochar, and manure) using Fourier transform ion cyclotron resonance mass spectrometry and metagenomic analysis. Compared to the control, manure fertilization increased the molecular chemodiversity of DOM by 33.2%, with recalcitrant compounds (e.g., highly unsaturated phenolic compounds and lignins) increasing by 47.2%. In contrast, labile compounds (e.g., aliphatics) decreased by 73.5%. Compared to straw treatment, manure application significantly increased the average conversion rate of dissolved organic matter (DOM). This process was accompanied by a significant increase in the Shannon index of the soil microbial community (p < 0.05) and upregulation of ABC transporter-encoding genes (e.g., livK, livM). DOM composition directly governed transformation potential (p < 0.01), whereas functional genes enhanced transformation indirectly by modulating DOM composition. This study elucidates microbial-mediated DOM transformation mechanisms under varying organic fertilization practices, providing a scientific basis for optimizing soil organic matter management in paddy ecosystems. Full article

Understanding the long-term evolution of soil carbon pools and dissolved organic matter (DOM) is crucial for evaluating carbon cycling and soil fertility in paddy ecosystems. This study investigated the changes in soil organic carbon (SOC), dissolved organic carbon (DOC), and DOM optical characteristics across an 8–63-year rice cultivation chronosequence in the western Jilin irrigation district of northeastern China. Soil samples were collected from five depth intervals (0–10, 10–20, 20–30, 30–40, and 40–50 cm) to assess physicochemical properties, ultraviolet–visible (UV-Vis) absorption, and three-dimensional excitation–emission matrix (EEM) fluorescence features. The results showed that long-term rice cultivation reduced soil salinity and alkalinity while significantly increasing SOC and DOC contents. The UV–Vis indices (SUVA₂₅₄, SUVA₂₆₀, SUVA₃₀₀) increased with cultivation duration, whereas E2/E3, E4/E6, and SR decreased, indicating enhanced aromaticity, humification, and molecular weight of DOM. Fluorescence analysis revealed a gradual transformation from protein-like to humic-like components, supported by PARAFAC modeling that identified four dominant components (two humic-like and two protein-like). Correlation and PLS-SEM analyses demonstrated that cultivation duration positively influenced soil carbon accumulation and DOM humification, while soil depth exerted a negative effect. Soil carbon acted as the core mediator linking UV–Vis and EEM indices, explaining more than half of the observed variance. Overall, long-term rice cultivation promoted carbon stabilization and humic substance formation, improving soil quality and carbon sequestration potential in saline–alkaline paddy soils. These findings provide valuable insights into the spectroscopic mechanisms of DOM transformation and the sustainable management of carbon processes in temperate agroecosystems. Full article

Nutrient cycling has barely been studied in acidic environments and may have an important influence on the evolution of the microbial communities. In this research, we studied nutrient sources and fluxes in acidic metal-mine pit lakes to evaluate their relationship with the lakes’ microbial ecology. Nutrient concentrations (including phosphorus, nitrogen, and dissolved inorganic carbon) increase with depth in all the studied pit lakes. Phosphorus comes mainly from the leaching of the host rock and is rapidly scavenged from the aqueous phase in the oxygenic and Fe(III)-rich mixolimnion due to adsorption on ferric precipitates (schwertmannite, jarosite), which leads to an important P-limitation in the photic zone. Below the chemocline, however, the sum of phosphorus inputs (e.g., settling of algal biomass, desorption from the ferric compounds, microbial reduction of Fe(III)-sediments) sharply increases the concentration of this element in the anoxic monimolimnion. Nitrogen is very scarce in the host rocks, and only a limited input occurs via atmospheric deposition followed by N-uptake by algae, N-fixation by acidophilic microorganisms, sedimentation, and organic matter degradation in the sediments. The latter process releases ammonium to the anoxic monimolimnion and allows some nitrogen cycling in the chemocline. Soluble SiO₂ in the mixolimnion is abundant and does not represent a limiting nutrient for diatom growth. Differences in phytoplankton biomass and extent of bacterial sulfate reduction between relatively unproductive lakes (San Telmo) and the more fertile lakes (Cueva de la Mora) are likely caused by a P-limitation in the former due to the abundance of ferric iron colloids in the water column. Our results suggest that phosphorus amendment in the photic zone could be an efficient method to indirectly increase acidity-consuming and metal-sequestering bacterial metabolisms in these lakes. Full article