Acid mine drainage (AMD) originates from mineral extraction and processing operations, exhibiting high acidity and containing elevated concentrations of metals and sulphates, which frequently pose significant environmental challenges. This study combined biochar with clay minerals to prepare two magnetic biochar-montmorillonite composites (FMBC1 and FMBC2) via coprecipitation-pyrolysis and impregnation-pyrolysis methods for investigating their removal efficiency and mechanisms for Cu, Pb, and Cd from metal solutions. Adsorption results indicate that at a dosage of 1.5 g/L, both FMBC1 and FMBC2 achieve removal efficiencies exceeding 99% for Cu (100 ppm), Pb, and Cd (50 ppm). Material characterization revealed that functional group complexation, crystallization-precipitation, possible ion exchange and reduction precipitation were the mechanisms by which FMBC1 and FMBC2 interact with Cu, Pb, and Cd in solution. Furthermore, FMBC1 and FMBC2 effectively removed Cu, Pb, and Cd from synthetic wastewater and could be recovered rapidly via magnetic attraction. Following desorption with EDTA-HCl, adsorbed FMBC1 and FMBC2 can be reused. The findings of this study provide potential theoretical foundation for treating heavy metals in AMD.

Lithium slag (LS) is difficult to utilize due to potential environmental risks. The current utilization of LS is focused on building materials and mine backfilling, and there are no reports on the preparation of environmental remediation materials (ERMs). A synergistic modification strategy combined calcination and hydrothermal activation was applied to transform LS into ERMs (TLs and Mn@TLs) for the adsorption of heavy metals in aqueous solution. TLs and Mn@TLs were rich in gehlenite (Ca2Al2SiO7) and dicalcium silicate (Ca2SiO4). The effects of pH, adsorbent dosage, contact time, temperature, and coexisting ions on the adsorption of Cd2+ and Pb2+ were systematically studied. At higher concentration ranges, the removal efficiency can exceed 98%. Both adsorbents showed excellent performance across a broad pH range (3-10). The Langmuir model fitting results indicate that the maximum adsorption capacity of TLs for Cd2+ was 245.1 mg/g at 318 K, and Mn@TLs demonstrated a capacity of 652.0 mg/g for Pb2+ at 298 K. The adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm model, specifically indicating monolayer chemisorption, mainly driven by ion exchange, chemical precipitation, and surface complexation. Compared to other mineral materials, activated carbon, biochar and activated sludge, TLs and Mn@TLs has better adsorption performance. The synergistic modification has successfully achieved heavy-metal detoxification and provides a technically feasible method for high-value utilization of LS.

Blast furnace slag (BFS) is an industrial by-product that generates large volumes of waste and poses potential environmental risks, necessitating its safe utilization. In this study, iron (hydr)oxide modified blast furnace slag (FBFS) was prepared by loading iron (hydro)oxides onto BFS for the remediate of lead (Pb) and cadmium (Cd) from aqueous solutions and soil. This adsorbent not only provides a novel approach for valorizing BFS but also prevents the agglomeration of iron (hydr)oxide particles, resulting in more surface functional groups (such as Fe–O and –OH) and an increased specific surface area. The results showed that the adsorption process of Pb fit the PSO and Langmuir models, and that of Cd followed the Elovich and Langmuir models. The maximum adsorption capacities of Pb and Cd by FBFS2 and FBFS6 in single-component system were 352.93, 395.15, and 112.34, 119.04 mg·g−1, respectively. In binary system, Pb exhibited a stronger inhibitory effect on Cd adsorption. The underlying mechanisms, including ion exchange, complexation, precipitation, and flocculation. In addition, FBFS significantly reduced the bioavailability of Pb, Cd and Zn in the soil, decreased by 20.03

The contrasting geochemical properties of heavy metals and metalloids pose a substantial challenge to their simultaneous removal and stabilization. In this study, a novel iron-manganese oxide-modified montmorillonite composite (FMO-Mt) was synthesized via co-precipitation to achieve the simultaneous removal and stabilization of Pb, Cd, and As in contaminated water and soil. Loading Fe/Mn oxides onto montmorillonite created multifunctional reactive site that combine cation exchange, surface complexation, and redox activity. The maximum adsorption capacities of FMO-Mt for Pb, Cd, and As were 193.6, 59.5, and 49.1 mg·g-1, respectively. In multi- component system systems, Pb and Cd exhibited competitive adsorption, whereas the coexistence of As with Pb or Cd produced synergistic removal. FMO-Mt effectively reduced metal(loid) mobility and bioavailability in soil. After 150 days with 3% FMO-Mt under the optimized conditions (30% soil moisture and 30 °C), the TCLP-leachable concentrations of Pb, Cd, and As decreased by 76.00%, 50.91%, and 94.97%, respectively, and the bioavailable concentrations decreased from 12.1, 1.9, and 47.4 mg·kg-1 to 7.38, 0.9, and 27.5 mg·kg-1. Besides, FMO-Mt exhibited environmental stability under simulated acid rain leaching. After 14 cycles, the reducing Pb, Cd, and As release by 88.75%, 94.12%, and 92.32%, respectively. Additionally, FMO-Mt enhanced soil enzyme activities and microbial metabolic activity, and decreased Pb, Cd, and As concentrations in ryegrass shoots by 86.9%, 65.5%, and 74.6%, respectively. The mechanisms of FMO-Mt including, Pb and Cd primarily through ion exchange and coordination complexation, whereas As was oxidized by Mn oxides and subsequently immobilized through inner-sphere As-O-Fe/Mn complexes. Overall, FMO-Mt provides an effective strategy for the simultaneous remediation of Pb, Cd, and As contaminated water and soil, and is a promising amendment.

Heavy metal ions such as Pb(II) and Cd(II) in aquatic environments and contaminated soils pose severe risks to ecosystems and human health, thereby necessitating their effective removal and immobilization. In this study, a phosphate-functionalized attapulgite material (C-ATP) was synthesized through a calcination-assisted modification strategy, achieving efficient phosphate incorporation while preserving the intrinsic crystalline framework of attapulgite (ATP). The resulting C-ATP exhibited significantly enhanced maximum adsorption capacities for Pb(II) and Cd(II), with increases of 80.89 % and 21.44 %, respectively, compared to unmodified ATP. Moreover, C-ATP exhibited remarkable adsorption stability over wide variations in pH and temperature, while sustaining high adsorption performance even under elevated concentrations of competing Ca(II) ions. In soil remediation experiments, C-ATP achieved immobilization efficiencies of 77.9 % for Pb(II) and 35.59 % for Cd(II) within 7 days, which were 2.8 and 1.5 times higher than those of unmodified attapulgite, and it maintained stable solidification performance after 56 days. X-ray photoelectron spectroscopy (XPS) analysis verified that the phosphate functionalities were actively involved in the adsorption of heavy metal ions through the generation of inner-sphere coordination complexes at the material surface. Atomic force microscopy (AFM) further revealed that phosphate groups exhibited stronger binding affinity toward Pb(II) than the original hydroxyl groups on the attapulgite surface, providing a molecular-level explanation for the superior performance of C-ATP. This work provides a simple and cost-effective strategy for fabricating phosphate-modified attapulgite, elucidating the molecular mechanism by which phosphate groups enhance adsorption performance, and offering new insights into efficient heavy metal removal and contaminated soil remediation.

The low efficiency of mine tailings utilization in alkali-activated cemented backfill is commonly attributed to the adoption of universal mix designs that overlook the chemical heterogeneity of tailings. This study investigates the role of the tailings Ca/Si ratio in controlling reaction mechanisms, gel chemistry, and engineering performance of high-Ca/Si alkali-activated materials (AAMs) for backfill applications. High-calcium iron ore tailings (IOT) and high-silica nickel smelting slag (NSS) were incorporated into a high-Ca/Si AAM system. Mechanical strength, water resistance, pore structure, phase assemblage, and gel composition were systematically characterized using unconfined compressive strength (UCS) tests, softening coefficient measurements, XRD, FT-IR, SEM-EDS, and leaching analysis. The results demonstrate two distinct activation mechanisms governed by the effective Ca/Si ratio. IOT participates in an incremental optimization pathway, where calcium-rich tailings promote the formation of a dense C-(A)-S-H gel matrix, resulting in a 28-day UCS of up to 5.25 MPa, low total porosity (16.66%), and excellent water resistance with a softening coefficient exceeding 0.97. In contrast, NSS follows a reconstitutive activation pathway characterized by extensive dissolution and reorganization of silicate phases into N-A-S-H-dominated gels, leading to rapid early strength development, with a 73.57% increase in UCS from 3 to 7 days at a binder-to-tailings ratio of 1:6. SEM-EDS statistical analysis confirms that the Ca/Si ratio governs the transition between C-(A)-S-H- and N-A-S-H-dominated gel systems, which directly determines pore structure and strength evolution. These findings indicate that mine tailings act as chemically active components rather than inert aggregates, and that Ca/Si ratio is a critical parameter for the tailored design of alkali-activated cemented backfill using diverse tailings.

Magnetite-modified attapulgite (ATP@MG) composites with different MG/ATP mass ratios were synthesized for the simultaneous removal of Pb(II), Cd(II), and As(III) from aqueous solutions. Among them, ATP@MG-0.5 exhibited the highest adsorption capacities of 194.90, 47.58 and 41.73 mgg(-1) for Pb(II), Cd(II), and As(III), respectively. Adsorption isotherms followed the Redlich-Peterson model for Pb(II) and Cd(II) and the Freundlich model for As(III), while kinetics conformed to the Elovich model. In multiple systems, the affinity order was Pb(II)>As(III)>Cd(II). The characterization results explicated the related mechanisms, including electrostatic attraction, surface complexation, precipitation and redox processes. Density functional theory (DFT) calculation revealed adsorption energies of -2.29, -0.815, and -1.43 eV for Pb(II), Cd(II), and As(II), respectively. In addition, Pb(II) and Cd(II) were coordinated with O atoms, whereas As(III) formed bidentate complexes with Fe atoms. This study enhances the understanding of the molecular mechanism of the selective adsorption of magnetite modified attapulgite and demonstrates its potential for treating co-contaminated waters containing both cationic and anionic metal(loid)s.

The low activity and expansion risk of steel slag limit its large-scale utilization in cementitious systems. This study developed an alkali-sulfate synergistic activation method to prepare binder with steel slag content exceeding 50 wt%. The effects of alkali activator dosage, modulus, steel slag and flue gas desulfurization gypsum content on the mechanical properties and workability were systematically investigated. With a mix of 60% steel slag, 30% fly ash, 10% desulfurization gypsum and activated by additional 20% alkali activator with modulus 1.0, the 28-day compressive strength reached 12.85 MPa, along with excellent volume stability. Microstructural characterization revealed that the main hydration products are C-A-S-H and ettringite, which jointly form a dense microstructure. When used to solidify lead-zinc tailings for backfill, the binder yielded satisfactory strength and effectively immobilized heavy metals (Pb, As, Cd, Zn), with leaching concentrations meeting environmental standards and immobilization efficiencies > 80%. Heavy metals were primarily immobilized through physical encapsulation, ion exchange, and co-precipitation. This study elucidates the hydration and mechanisms of high-content steel slag systems under alkali-sulfate synergistic activation, providing a sustainable technical framework for large-scale utilization of steel slag and tailings management.

The co-occurrence of arsenic (As), lead (Pb), and cadmium (Cd) in smelting soils presents major challenges due to their contrasting geochemical behaviors. This study investigates the efficacy of Fe-modified clay minerals (ATP@MG) in simultaneous stabilization of As, Pb, and Cd co-contaminated soil, and revealed the impact on soil bacterial community succession. The results showed that ATP@MG amendment substantially altered soil iron speciation, particularly increasing amorphous (Fe0) by 3.04-fold at a 5% dosage. The TCLP extractable of As, Pb, and Cd decreased by 83.46%, 75.02%, and 18.40%, respectively, accompanied by marked increases in their residual fractions (84%, 84% and 69%), compared with the control. Simulated acid-rain leaching confirmed that ATP@MG strengthened Fe-metal(loid) associations and significantly reduced long-term leaching risks. Multi-mechanistic immobilization involved electrostatic attraction, complexation (C=O, -OH and Fe-O), Fe(II)/Fe(III)-mediated redox and physical encapsulation within soil aggregates. ATP@MG also enhanced microbial metabolic activity and reshaped bacterial community composition. ATP@MG selective specific functional bacterial (e.g. Proteobacteria (55.81%), Chloroflexi (13.19%)), followed by ecological succession toward a more stable community structure. Redundancy analysis and PLS-PM indicated that ATP@MG-induced changes in soil pH, EC, Fe0, and Fed were the dominant drivers shaping microbial composition and reducing metal(loid)s bioavailability. Besides, ATP@MG reduced network complexity to enhanced cooperative interactions, and toward ecological recovery to improve the nutrient cycling capacity. Overall, Fe-modified clay minerals demonstrated strong potential for simultaneous stabilization of As, Pb and Cd, while promoting microecological recovery in co-contaminated soils.

Research on the metabolic activity of sulfate-reducing bacteria (SRB), traditionally classified as strict anaerobes in oxygen-containing environments, has received much attention. A popular hypothesis is that oxygen is toxic to SRB; however, the relationship between SRB and oxygen is more complex than imagined. Oxygen can also be beneficial to SRB. This review examines the strategies SRB employs to thrive in oxygenated environments, including defense, detoxification, and energy metabolism. We compiled evidence from physiological and biochemical research conducted over the past three decades, as well as the latest published findings from genomic and transcriptomic studies. The present paper provides an overview of the behavioral mechanisms of SRB, gene expression reprogramming, molecular mechanisms for defending against oxygen toxicity, and DNA and protein repair mechanisms after oxidative damage. An innovative summary of the growth and metabolic potential of SRB in oxidative environments is provided. Some SRB can undergo oxygen metabolism to generate energy and support growth. For SRB, toxic oxygen concentrations can be decreased by reduction, and the residual oxygen could be utilized as a substrate for SRB energy metabolism. This review offers a new perspective on the relationship between SRB and oxygen and discusses the role of SRB’s oxygen-resistance mechanism in environmental site remediation and wastewater treatment. This information is of great significance for understanding and developing environmental biotechnology applications related to SRB.

In this study, lead-zinc smelting slag (LZSS) was innovatively used as a Mn-based catalyst in combination with the biodegradable picolinic acid (PICA) to construct an activated periodate (PI) system for the degradation of the emerging pollutant benzotriazole (BTA). The LZSS/PI/PICA system generated multiple reactive species (highvalent metal species, IO3 center dot, center dot OH), but oxidation of BTA occurred mainly through a Mn(V)-mediated nonradical process. The combined experimental and density functional theory calculations elucidate the critical steps in MnPICA/PI interactions, revealing Mn(III) species as critical metastable precursor of the Mn(V)-oxo species were involved in the oxidation process. PICA serves two functions in the combined system via a heterogeneoushomogeneous coupled process: 1) chelates inert Mn oxides on the LZSS surface and transforms into Mn-PICA complex with a catalytic activity; 2) prevents disproportionation of transient Mn species (Mn(III)), promoting the redox cycling of Mn species. LZSS/PICA (i.e. Mn-PICA) acts as an electron relay that shuttles electrons from BTA to PI in the reaction process to achieve the pollutant removal. Notably, the Mn species on the LZSS surface that can be complexed by PICA are related to the geochemical fractions of LZSS, which further influences the oxidative performance of the system. Because of the dominant role of selective Mn(V), the LZSS/PI/PICA system exhibited resilience to water matrices (except for high concentrations of HCO3-) and high efficiency in real waters. Overall, this study sheds light on the previously unrecognized role of the functional ligand PICA-assisted heterogeneous catalytic system and broadens the application of LZSS in the field of environmental remediation.

The incorporation of high-silica silicic gangue tailings into ordinary Portland cement (OPC) backfill significantly depresses the Ca/Si ratio, which inhibits the formation of strength-giving hydration products like C-S-H gel and leads to poor mechanical properties. To resolve this fundamental issue, this study pioneers a high-Ca/Si ratio design via a novel "waste-treats-waste" strategy. A novel high Ca/Si ratio all-solid waste-based cementitious material (ACM)-synthesized from blast furnace slag, steel slag, carbide slag, and gypsum (Ca/Si = 2.95)-was integrated with iron tailings (IOT) and nickel smelting slag (NSS) to establish a fully waste-derived backfill system. Through systematic optimization of slurry concentration (74-80 %) and binder-to-tailings ratios (1:2-1:8), the hydration dynamics, mechanical performance, and environmental safety were evaluated. Key findings include: (1) The tailored Ca/Si ratio (2.0-3.0) activated silicic components in tailings via alkaline dissolution and Ca2+-mediated depolymerization, promoting dense C-(A)-S-H/AFt gel networks. (2) The 28-day unconfined compressive strength (UCS) reached 3.66 MPa (IOT) and 3.55 MPa (NSS) at 76 % slurry concentration and 1:6 binder ratio, surpassing conventional cement-based systems by 15-30 %. (3) Elevated Ca/Si ratios enhanced environmental safety, suppressing heavy metal leaching (compliant with GB/T 14848-2017) while reducing CO2 emissions by 92 % and material costs by 60 % compared to cement. (4) NSS exhibited selfcompacting microstructures (fractal dimension D = 1.84) with exceptional stability (settling rate <= 2.2 %), whereas IOT achieved optimal hydration at 76 % concentration. The study resolves critical bottlenecks in ultrafine tailings utilization, offering a scalable "waste-treats-waste" solution for low-carbon mining. Limitations in Fe leaching thresholds (IOT76-18) and thermal management strategies warrant further machine learning-driven optimization. This work pioneers a paradigm for multi-waste synergy, balancing mechanical robustness, ecoefficiency, and industrial feasibility in backfill engineering.

Waste-derived geopolymers have garnered widespread attention for heavy metal immobilization in contaminated soils, but the simultaneous solidification of cationic heavy metals and As(III) remains challenging. As(III) exists as arsenic acid (H3AsO3) and/or anionic species (e.g., H2AsO3-), which exhibit low affinity for the negatively charged geopolymer matrix and are difficult to immobilize during hydration. Potassium permanganate (KMnO4), as a strong oxidant and arsenic-affinity reagent, is expected to significantly improve As(III) immobilization, yet its effects on the speciation, occurrence, and fate of As in geopolymer systems remain unclear. This study develops a novel, sustainable strategy by combining a waste-derived steel slag-based geopolymer (SSG) with KMnO4 and ferrous sulfate (FeSO4) for the effective treatment of Pb-Cd-As co-contaminated soil. After 28 days of curing, the composite system (20% SSG + 0.1% KMnO4 + 1% FeSO4) yields exceptionally low leaching concentrations of 12.15 μg/L for Pb, 14.96 μg/L for Cd, and 21.63 μg/L for As, all complying with stringent Chinese regulatory limits. Mechanistic investigations reveals that the geopolymer gel effectively immobilizes Pb and Cd through physical encapsulation, ion exchange, and chemical bonding within its aluminosilicate network. Critically, the chemical additives plays a vital synergistic role: KMnO4 oxidizes highly mobile and toxic As(III) to As(V), which is subsequently sequestered via adsorption and co-precipitation with iron (oxy)hydroxides formed from FeSO4 hydrolysis. Furthermore, this approach reduces the treatment cost by 31.19% and decreases carbon emissions compared to ordinary Portland cement. This work provides a cost-effective and environmentally benign "waste-treats-waste" paradigm for the remediation of complexly contaminated soils.

Arsenic (As) contamination threatens soil ecological security and human health due to its high toxicity and mobility. In this study, an As-tolerant fungus, Trichoderma viride YP-24, was isolated from As-contaminated soil and used to construct a synergistic remediation system with ryegrass (Lolium perenne L.). Pot experiments demonstrated that the synergistic system significantly promoted ryegrass growth, decreased As accumulation in plant tissues by 49 ± 4.20%, and achieved an As immobilization efficiency of 54 ± 3.86%. Meanwhile, soil enzyme activities were significantly enhanced. The synergistic system shifted As from mobile to stable fractions, decreasing mobile fractions (F1+F2) from 20 ± 0.13% to 16 ± 0.45%, while increasing stable fractions (F4+F5) from 28 ± 0.73% to 36 ± 1.31%, thereby reducing As mobility and bioavailability. Co-occurrence network analysis based on 16S rRNA gene and ITS1 metabarcoding revealed increased microbial diversity and enrichment of Ohtaekwangia and Fusarium, which are associated with metal(loid) immobilization and carbon and nitrogen cycling. The shifts in microbial community structure were closely associated with As fraction transformation and soil enzyme activities (Mantel test, P < 0.05). Overall, the synergistic system reshaped rhizosphere microbial communities, promoted As stabilization, and improved soil quality, providing mechanistic insights into microbial-enhanced phytoremediation of As-contaminated soils.

p-Chloroaniline (PCA), a persistent and toxic pollutant in mine tailings, necessitates cost-effective remediation strategies. This study evaluates the degradation of PCA by Fe2+/Fe3+-catalyzed sodium persulfate (SPS) and sodium percarbonate (SPC) oxidation enhanced by UVA-B irradiation. Among the systems tested, the UVA-B/ Fe2+/SPS system achieved 96.2% PCA removal within 180 min, outperforming other configurations. Radical scavenging experiments and density functional theory (DFT) calculations suggested that SO4 center dot- and center dot OH radicals were the primary reactive species in SPS systems, while center dot OH and O2 circle- were identified as the major reactive species in SPC systems. DFT further revealed vulnerable sites on PCA for radical attack, supporting proposed degradation pathways. ECOSAR toxicity assessment revealed that although PCA acute toxicity decreased, certain intermediates (e.g., azo-compounds) retained high chronic toxicity, highlighting the importance of process optimization. This study provides novel insights into the degradation mechanisms of PCA, establishing a mechanistic foundation for designing solar-enhanced, iron-coupled advanced oxidation processes for industrial-scale remediation of halogenated aromatics in mining environments.

UV filters, commonly found in personal care products, undergo chlorination in swimming pools, forming disinfection by-products (DBPs) with potential toxicological and health impacts. This study aimed to evaluate the cytotoxic, genotoxic, and biochemical effects of three UV filters - 2-hydroxy-4-methoxybenzo-phenone (benzophenone-3 or BP3), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), and 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone) - and their chlorinated by-products in human lung epithelial (A549) cells and investigate their interaction with lipid membranes under visible and UV light conditions. Parent UV filters exhibited moderate cytotoxicity at higher concentrations (BP-3: 167 μM; DHHB and avobenzone: 16.7 μM), whereas their chlorinated derivatives demonstrated enhanced cytotoxic effects, particularly 3,5-dichloro BP3 (BP3-Cl: 16.7 μM; BP3-diCl: 33.3 μM) and 2-chloro avobenzone (16.67 μM). Significant increases in glutathion-S-transferase (GST) activity were observed for 3,5-dichloro BP3 at concentrations of 74.5 μM and 166.67 μM, indicating possible oxidative stress responses, but no genotoxic effects were observed suggesting other mechanism of toxicity. Membrane interaction studies showed that 3,5-dichloro BP3 caused vesicle deformation under UVA exposure (385-400 nm), highlighting the potential of chlorinated by-products to alter membrane stability. Chlorination enhances the cytotoxic potential of UV filters, likely through oxidative stress and membrane disruption. These findings emphasize the need for further research on the environmental and health implications of UV filter DBPs, particularly in contexts of prolonged UV exposure such as swimming pool environments.

All-solid waste cementitious materials (ACM) offer sustainable solid waste valorization but face composition optimization challenges. This study pioneers a hydration-phase-precursor-directed design strategy by classifying wastes into functional components: alkali activators (e.g., carbide slag, steel slag), aluminosilicate precursors (e. g., blast furnace slag), and auxiliaries (e.g., gypsum). This functional classification enables precise control over precursors governing hydration phases. Through simplex centroid optimization, ACM achieved dominant formation of target hydration products: calcium aluminosilicate hydrate (C-(A)-S-H) gel and ettringite (AFt). Key performance metrics include 21.73 MPa uniaxial compressive strength (28d), 138 mm fluidity, setting time compliance with GB 175-2023, water resistance exceeding T/CBMF 36-2018 requirements, and heavy metal leaching below Class II groundwater limits. Multi-scale characterization confirmed precursor-directed formation of Al-substituted C-(A)-S-H (via XPS) and interlaced AFt-C-(A)-S-H microstructures (via SEM). Crucially, ACM reduced energy intensity by 55-63 %, carbon emissions by 92 %, and costs by 57-70 % versus Portland cement, demonstrating scalable pathways for low-carbon construction.

The use of all-solid waste cementitious materials (ACM) in coal mine grouting backfill offers substantial green, low-carbon, and energy-saving benefits. This study systematically examines the effects of combining carbide slag (CS), fly ash (FA), and ground granulated blast furnace slag (GGBS) on the strength, workability, hydration characteristics, and microstructure of ACM. The utilization of sulfur-containing CS was achieved. The detrimental effects of delayed FA reaction and prolonged setting time can be mitigated by the introduction of high alkalinity or an increase in the Ca/Si ratio. The compressive strength may also be enhanced. The addition of excessive alkalinity (10%) will result in a prolongation of the setting time. The primary hydration products include calcium aluminum silicate hydrate and magnesium-aluminum layered double hydroxide. Low Ca/Si ratios favor alkali metal ion charge balance, facilitating the transformation of silicate gels from single to double chains, while excessively high ratios reduce polymerization. Gmelinite forms when the (Ca+Na)/(Al+Si) ratio exceeds 1.6, and high NaOH concentrations inhibit ettringite formation. Validation shows that a GGBS:FA:CS=3:1:3 mix with 4% alkali binder (Group A2) meets mine grouting backfill criteria, with 80% lower carbon emissions, 68% lower energy intensity, and 50% lower cost than cement. This research offers a viable pathway for the comprehensive utilization of multi-solid waste in mining applications.

Aniline, a common derivative pollutant found in non-ferrous metal(loid) tailings due to the usage of flotation reagents, is a significant residual chemical and requires remediation in tailings waste management. This research identified a Staphylococcus aureus CUGB-LJL5 as a proficient aniline-degrading bacterium isolated from tailings soil. This strain was successfully used to establish a two-step strategy of microbiological treatment followed by an advanced oxidation process (AOP) to eliminate high concentrations of aniline (1000 mg/L). The results indicate that the combined microbial AOPs technique exhibits superior efficiency in degrading aniline at high concentration of 1000 mg/L, achieving a degradation rate of 99.89% with only 1.08 mg/L remaining. Optimal conditions for this process involved the addition of 5 mM peroxymonosulfate (PMS) and 1 mM Fe(II) after inoculating with a 3% bacterial culture for 96 h at a pH of 7 and a temperature of 30 degrees C. PCR and radical scavenger experiments suggest that the microbial phase primarily involves enzyme-mediated removal, while the subsequent AOPs phase was mainly driven by free radical (SO4 center dot-) reactions. Three different degradation pathways are proposed based on the aniline degradation byproducts determined by GC-MS. Including the elimination of aniline by the aniline dioxase pathway during microbial degradation and promotes further mineralization by Fe (II) or Co(II)/PMS by both, hydroxylation and acetylation. Additionally, results from the cost analysis also highlight the potential and economic feasibility of the combined technology. In general, microbiological treatment post Fe(II)/PMS process is a green, efficient and economical method for remediating high concentrations of aniline in non-ferrous(loid) tailings environments.

A magnetic field-assisted reduction method was employed to synthesize nano-Co-zeolite (NCZ) by controllable loading nanosized cobalt onto zeolite. Careful investigations suggest that the magnetic field applied during the synthesis process has significant influence on the morphology and crystal structure of NCZ. With the increasing of magnetic field, the morphology of the surface-coated cobalt gradually transitioned from irregular, smaller flakes to larger, more uniform flakes with a higher specific surface area, culminating in the formation of a short- chained, alternating stacked nanostructure. The synthesized NCZ samples were used to activate peroxomonosulfate for the catalytic degradation of ciprofloxacin. It is shown that the NCZ synthesized under magnetic field exhibited a much higher catalytic activity compared to those synthesized with no magnetic field, owing to the increase of specific surface area and change of structure of the samples. The highest ciprofloxacin removal of 88.4% was observed in NCZ-100, which was synthesized under 100 mT. Since NCZ has strong magnetism, efficient solid-liquid separation and recycling could be achieved. The catalytic mechanism of NCZ was discussed.