From pollution to action: How soil extraction methods for potentially harmful elements influence human health risk estimates.

Application of red mud-derived materials: integrated analysis of synergistic heavy metal remediation in soil and aquatic systems based on interfacial processes and molecular mechanisms

The sustainable mitigation of antibiotic and herbicide residues requires materials that integrate effective contaminant sequestration with soil quality improvement. Here, we present a novel, scalable strategy for synthesizing artificial humic substances (AHS) from poplar bark via alkaline hydrothermal humification, which accelerates natural humification pathways and generates a supramolecular structure rich in carboxyl, pHenolic, and quinone functional groups. The engineered AHS was assessed for selective removal of tetracycline (TC), sulfamethoxazole (SMX), and atrazine (ATZ). Under optimized neutral conditions (pH 7.0, ambient temperature), AHS achieved adsorption capacities of 65.8, 10.7, and 10.8 mg/g for TC, SMX, and ATZ, respectively, driven primarily by hydrogen bonding, π–π stacking, and electrostatic forces. Kinetic analysis followed a pseudo-second-order model, and equilibrium data were consistent with the Langmuir isotherm (R 2 ≥ 0.985), indicating monolayer adsorption on a mesoporous surface. Competitive adsorption experiments demonstrated strong selectivity toward TC (K TC/SMX = 5.21; K TC/ATZ = 2.56). Soil amendment with AHS significantly enhanced pollutant immobilization, achieving >95% removal of TC and SMX after four weeks of aging. Dynamic leaching experiments demonstrated that a layered AHS-soil configuration functions as a superior reactive barrier compared to homogeneous mixing. Collectively, these results demonstrate that poplar bark-derived AHS offers a robust, bifunctional platform for integrated water purification and soil remediation, providing a practical and environmentally sustainable approach to mitigate organic pollutants. • Artificial humic substance synthesized from poplar bark via hydrothermal treatment. • AHS effectively adsorbed antibiotics and herbicides from aqueous and soil systems. • Adsorption followed the pseudo-second-order kinetics and Langmuir isotherm model. • AHS-amended soils demonstrated contaminant removal after four weeks of incubation. • Layered AHS configuration exhibited superior leaching control and pollutant retention.

Fe3O4-based nano-fertilizers for simultaneous nutrient supply and remediation of contaminated soils.

Nanoplastics migration in hydroxyapatite-amended porous media: Integration of XDLVO theory and two-site kinetic modeling.

Enhanced resistance of ants (Formica japonica) reared on biochar-enriched soil to stress induced by heavy metals: Programming of the molecular defense system.

Carbonisation of rare earth elements hyperaccumulator (Dicranopteris pedata) for remediation of heavy metal contaminated Soil: A Case study.

The escalating generation of urban lignocellulosic waste poses significant environmental and resource management challenges, necessitating sustainable valorization strategies. This article critically examines the conversion of urban lignocellulosic biomass into molecularly tailored nanomaterials for targeted soil and wastewater remediation. Emphasis is placed on the synthesis methodologies, molecular engineering approaches, and the intrinsic physicochemical properties governing their remediation performance. Key factors influencing material characteristics, including pyrolysis temperature, heating rate, residence time, and feedstock composition, are systematically analyzed. Tailored nanomaterials produced at elevated pyrolysis temperatures exhibit enhanced microporosity, increased specific surface area, and greater hydrophobicity, favoring the adsorption of non-polar organic contaminants.Conversely, low-temperature derived nanomaterials, enriched with oxygenated functional groups, demonstrate superior affinity towards polar organic and inorganic pollutants via surface complexation, electrostatic attraction, and precipitation mechanisms. The review further addresses critical challenges such as feedstock variability, process scalability, environmental risks, and regulatory considerations associated with field-scale applications.Future research directions emphasize the precision design of nanomaterials for contaminantspecific remediation, process optimization for large-scale deployment, and comprehensive environmental impact assessments. Overall, this study highlights the transformative potential of urban biomass-derived nanomaterials in advancing sustainable environmental remediation technologies and contributing to circular economy frameworks.

Exopolysaccharide (EPS) synthesis of halophilic microorganisms is often reported as an adaptation to high-salt environments, and the unique structural and functional characteristics of these EPSs make them valuable biomaterials with promising application potential. A moderately halophilic strain, Vreelandella sp. DT-Z4, was isolated from Qinghai saline soil, and its EPS yield reached 3.09g/L after fermentation optimization. The polysaccharide fraction (designated EPS-Z4) was partially purified using ethanol precipitation, deproteinization, and dialysis processes, and subsequently characterized for monosaccharide composition, spectroscopic features, and morphological properties. Analytical results revealed that EPS-Z4 was a fructose-rich polysaccharide composed of 97.6% fructose, 1.4% glucose, and 0.5% uronic acid. Functional group analysis confirmed the presence of absorption peaks characteristic of polysaccharides. The polysaccharide showed a degradation temperature (Td = 275.9°C), water solubility (85.8%), and oil-holding capacity (321%). Morphological observations revealed a dense, layered network structure. Based on these physicochemical properties, the fructose-rich polysaccharide fraction EPS-Z4 may merit further investigation as a stabilizer in high-temperature food processing or as a biological agent for the remediation of saline-alkali soils.

Microwave-assisted pyrolysis of kraft lignin was used to produce highly porous carbonaceous materials for environmental applications (biochars). LignoForce hardwood (LFHL) and softwood (LFSL) lignins were mixed with 30% potassium phosphate (K3PO4) and pyrolyzed at 450 °C to produce 45-47% biochar after 25 min of microwave irradiation. A 10 L min-1 nitrogen flow was used for purging during the pyrolysis and cooling. Elemental analysis (CHNS-O) revealed that kraft lignins were highly deoxygenated, but nearly 26% of their original oxygen content remained after pyrolysis, suggesting retention of oxygenated compounds in the biochar structure. Nitrogen adsorption (BET), scanning electron microscopy (SEM), and X-ray diffraction (XRD) demonstrated the formation amorphous micro- and mesoporous carbonaceous materials with a high potential for water and soil remediation. Significant specific surface areas (142 and 202 m2 g-1 for LFHL-B and LFSL-B, respectively) were obtained for these lignin biochars, which were tested for methylene blue (MB) adsorption at pH 4.5, 6.0, 7.5, and 9.0. LignoForce lignin biochars presented an adsorption capacity of approximately 15.5 mg g-1 and a removal efficiency higher than 94%, especially at higher pH levels (>4.5). However, MB adsorption was slightly faster for LFHL-B compared to LFSL-B. These results position kraft lignin as a valuable carbon-accumulating raw material for environmental applications and establish MAP as a fast and energy-efficient route for their thermal conversion.

Permeation grouting is a ground improvement technique utilised to mitigate geotechnical disasters such as soil liquefaction. This study focuses on the use of suspension-type grout due to its potential for additional soil densification and material versatility. While centrifuge modelling can be utilised to assess permeation behaviour, testing under increased gravitational acceleration creates complications, including the accelerated settling of grout particles and challenges concerning remote operation. To overcome these limitations, a novel permeation setup was developed, featuring a modified bladder tank that enables remote permeation while preventing grout sedimentation. This was paired with a two-dimensional permeation apparatus designed to visualise the process while minimising boundary effects. Results confirm that controlled permeation was successfully initiated and sustained within the centrifuge field. This allowed for a clear assessment of grout flow, including the clogging mechanism and sedimentation. Image analysis further revealed that unclogging events led to an increased permeation area and that the particles remained stable and confined to the target zone post-permeation. The study successfully establishes a geotechnical centrifuge methodology for permeation experiments, generating foundational data that will enable future complex investigations into depth and soil variables necessary to enhance the efficiency of grouting as a soil remediation technique.

Zeolite-AMF application enhances wheat productivity, cadmium immobilization, and saline soil health under Cd-contaminated wastewater irrigation.

Remediation of thiamethoxam polluted soil by FeS2/Fe3O4 alkali-modified biochar: performance and mechanisms.

Chromium is a common contaminant in mineral soils and poses a severe threat to ecosystems and human health. Immobilization/stabilization is an efficient approach for in-situ remediation of Cr-contaminated soil, but more cost-effective and efficient immobilizing materials, particularly for soils with high Cr concentration, are still urgently needed. Herein, a novel carbon-based composite was developed using nitrogen-modified porous carbon (U-PC) and chitosan/zero-valent iron-modified porous carbon (CS-nZVI-PC). Stabilization experiment showed that CS-nZVI-PC exhibits better performance than U-PC in remediating Cr (VI) contaminated soil. The immobilization efficiencies of U-PC and CS-nZVI-PC after 28 d of treatment are 46.68% and 99.61%, respectively. Additionally, the active exchangeable and carbonate-bound forms of Cr reduce from 36.23% in the untreated group to 16.80% in the CS-nZVI-PC-treated group, while the stable organic combined and residue fractions of Cr increase from 63.77 to 83.20%. Mechanism studies for CS-nZVI-PC revealed that a combination of surface functional groups and reduction of hexavalent chromium plays the synergistic interaction between chitosan/carbon and zero-valent iron material during immobilizing. The main role in the immobilization process is the N-containing and O-containing functional groups of chitosan and carbon materials, as well as the enhanced reduction effect of zero-valent iron and Fe (II).

Contamination by potentially toxic elements (PTEs) in soil-rice systems poses serious threats to food safety and human health. A total of 225 soil samples and 90 rice samples were collected from typical rice-growing areas in Chongqing, Southwestern China, to investigate PTE sources and transfer in the soil-rice system. The concentrations of 11 PTEs (As, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se, and Zn) were determined, and their sources and migration behaviors were investigated using a Positive Matrix Factorization (PMF) model combined with enrichment and transfer indices. Results showed that Zn and Mn dominated in soils, while As, Cd, and Hg exhibited pronounced spatial heterogeneity and signals of exogenous disturbance. PMF identified five pollution sources in soils: geological background (39.5%), agricultural sources (34.8%), light industrial activities & sewage irrigation (17.8%), arsenic-enriched urban disturbance mixed source (5.7%), and industrial emissions & atmospheric deposition (2.2%). Within rice plants, Cd, As, and Se were notably enriched in roots (BCF > 2.6), while grain translocation was limited, indicating a protective barrier. PMF source analysis for rice identified industrial activities & traffic (40.8%), agriculture & irrigation water (34.5%), and coal combustion & waste disposal (24.7%) as major contributors. Transfer coefficient patterns suggested element-specific translocation within rice plants, with Cd showing relatively stronger upward movement, Zn preferentially enriched in stems, and grain accumulation remaining low for most elements. This study provides insights into PTE source-associated patterns and transfer dynamics in soil-rice systems, providing a theoretical basis for paddy soil remediation and agricultural product safety management.

Combined organic amendments reduce Cd accumulation in double-cropping rice by restructuring soil bacterial communities.

Total petroleum hydrocarbons (TPHs) are major components of crude oil and pose long-term environmental risks due to their persistence and toxicity in soil, water, and air. Although phytoremediation and bioaugmentation are promising remediation strategies, limited published studies have explored the combined effects of integrating plant, microbial, and mineral systems to enhance hydrocarbon degradation. This study for the first time investigates the combined application of Parthenium hysterophorus, hydrocarbon-degrading Pseudomonas aeruginosa RS6, and zeolite for the remediation of TPH-contaminated soil. Key physiological responses of the plants including chlorophyll content, shoot/root length, and biomass as well as soil properties (pH, moisture, EC, macronutrients) were determined. The combined treatment achieved the highest TPH reduction (85.52%) followed by P. hysterophorus + P. aeruginosa RS6 (80.37%), zeolite alone (29.61%), P. hysterophorus alone (20.39%), and the control (16.6%). These findings suggest that integrating mineral and microbial amendments enhances the phytoremediation efficiency of P. hysterophorus, likely by improving plant tolerance and soil conditions. This novel treatment combination offers a cost-effective, scalable strategy for remediating petroleum-contaminated soil.

Fe/Mg-LDH modified biochar for heavy metal soil remediation: Effects on microbial community structure and metabolic activity.

Potentiated remediation of imazethapyr-contaminated soil by phosphate-doped biochar immobilized with Bacillus cereus MZ-1.

Phosphorus immobilization in biosolids-impacted soils: Influence of amendment type and soil chemistry on environmental and agronomic outcomes.