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To reveal the enrichment characteristics and health risks of potential harmful heavy metal elements (PTEs) in the soil-vegetable system around different antimony mine waste residue areas, three villages around different types of waste residue storage yards (antimony ore waste rock, antimony ore smelting slag, antimony ore tailings) and a village downstream of Lianxi River under the joint influence of waste residues are selected as the sampling areas, and taking the soil-vegetable system within the sampling areas as the research object. The enrichment characteristics and health risk assessment of six types of PTEs, including Sb, As, Hg, Pb, Cd, and Zn, in soil and vegetable samples are discussed using methods such as statistics, transfer coefficient analysis, and in vitro digestion simulation. The results shows that the average content of six PTEs in the soil exceed the soil background value and risk screening value of Hunan Province. All vegetable samples show weak uptake of soil PTEs with mean bioaccumulation coefficient values below 0.12. The biological transfer coefficients of Pb, Cd, and Zn in PTEs of vegetable samples all exceed 1.0. The exposure risk index for antimony is greater than 1.0 in all four sampling areas, presenting a significant health risk to humans. The index HI used to evaluate the hazard of composite pollution is greater than 2.0 in all four sampling areas, and the main PTEs pollutants are Sb and Pb, the composite pollution has been a health risk to human beings. Research has shown that the soil in the four sampling areas has been contaminated and enriched by various PTEs, and vegetables pose health risks to local residents, requiring special attention. [ABSTRACT FROM AUTHOR]

In this study, a renewable and reusable immobilized Microcystis aeruginosa microsphere loaded with magnetic Nano-Fe3O4 composite adsorbent material is designed to study the treatment of wastewater containing heavy metal Sb(III). Through static absorption experiments combined with various characterization methods, this article studies the absorption process and mechanism of Sb(III), and investigates the optimal preparation conditions and environmental influencing factors. The results show that the optimal preparation conditions for immobilized Microcystis aeruginosa microspheres loaded with magnetic Nano-Fe3O4 adsorbent materials are 50.0% mass fraction of Microcystis suspension, 1.5% mass fraction of Nano-Fe3O4, and 2.5% mass fraction of sodium alginate. When the pH of the solution is 4, the reaction temperature is 25 °C, and the adsorbent dosage is 8.5 g/L, the removal rate of Sb(III) is the highest, reaching 83.62% within 120 min. The adsorption process conforms to the pseudo-second order kinetic model and Langmuir adsorption isotherm model, mainly characterized by chemical adsorption and surface complexation. Therefore, the composite material has been proven to be an efficient Sb (III) adsorption material. [ABSTRACT FROM AUTHOR]

With the development of industry, the concentration of lead (Pb) in water bodies is gradually increasing, the forms of Pb pollution in water are becoming increasingly diversified, and the environmental and human health hazards caused by Pb pollution are receiving increasing attention. A HCO–(Fe3O4)x composite adsorbent prepared by the coprecipitation method of Fe3O4 mixed in cerium-rich grinding and polishing sludge was used to remove Pb from water. The effects of Ce/Fe molar ratio, pH, dosing amount, and time on the adsorption of HCO–(Fe3O4)x for Pb removal were investigated and the adsorption isotherm model, adsorption kinetics, and adsorption mechanism were studied. The results showed that the maximum adsorption capacity of HCO–(Fe3O4)x on Pb(II) was 35.93 mg·g−1 at a Ce/Fe molar ratio of 1.5:1, pH 4–5, and temperature of 25 °C, and the removal rate could reach 96.05%; the process of Pb(II) adsorption by HCO–(Fe3O4)x was in accordance with the Langmuir isothermal adsorption model and the pseudo-second-order reaction kinetic model; chemisorption was dominant. Characterization results, such as EDS, XRD, and XPS, showed that the composite preparation of HCO with Fe3O4 increased the specific surface area of HCO–(Fe3O4)x and generated amorphous iron oxides, such as FeCe2O4, FeOOH, Fe3O4, and Fe2O3, which provided conditions for the formation of Fe-O-Pb and Ce-O-Pb complexes during the adsorption process, thus facilitating the adsorption removal of Pb(II). [ABSTRACT FROM AUTHOR]

Effective elimination of heavy metals from complex wastewater is of great significance for industrial wastewater treatment. Herein, bimetallic adsorbent Fe 3 O 4 –CeO 2 was prepared, and H 2 O 2 was added to enhance Sb(V) adsorption by Fe 3 O 4 –CeO 2 in complex wastewater of Sb(V) and aniline aerofloat (AAF) for the first time. Fe 3 O 4 –CeO 2 showed good adsorption performance and could be rapidly separated by external magnetic field. After five adsorption/desorption cycles, Fe 3 O 4 –CeO 2 still maintained good stability. The maximum adsorption capacities of Fe 3 O 4 –CeO 2 in single Sb(V), AAF + Sb(V), and H 2 O 2 +AAF + Sb(V) systems were 77.33, 70.14, and 80.59 mg/g, respectively. Coexisting AAF inhibited Sb(V) adsorption. Conversely, additional H 2 O 2 promoted Sb(V) removal in AAF + Sb(V) binary system, and made the adsorption capacity of Fe 3 O 4 –CeO 2 increase by 14.90%. H 2 O 2 could not only accelerate the reaction rate, but also reduce the optimal amount of adsorbent from 2.0 g/L to 1.2 g/L. Meanwhile, coexisting anions had little effect on Sb(V) removal by Fe 3 O 4 –CeO 2 +H 2 O 2 process. The adsorption behaviors of Sb(V) in three systems were better depicted by pseudo-second-order kinetics, implying that the chemisorption was dominant. The complexation of AAF with Sb(V) hindered the adsorption of Sb(V) by Fe 3 O 4 –CeO 2. The complex Sb(V) was oxidized and decomposed into free state by hydroxyl radicals produced in Fe 3 O 4 –CeO 2 +H 2 O 2 process. Then the free Sb(V) was adsorbed by Fe 3 O 4 –CeO 2 mostly through outer-sphere complexation. This work provides a new tactic for the treatment of heavy metal-organics complex wastewater. [Display omitted] • Adsorbent Fe 3 O 4 –CeO 2 effectively removed Sb(V) in Sb(V) + AAF complex wastewater. • The adsorption behavior of magnetic Fe 3 O 4 –CeO 2 on Sb(V) was mainly chemisorption. • Novel Fe 3 O 4 –CeO 2 +H 2 O 2 process enhanced Sb(V) adsorption in Sb(V) + AAF wastewater. • Mechanisms of removing Sb(V) in complex wastewater by Fe 3 O 4 –CeO 2 +H 2 O 2 were revealed. [ABSTRACT FROM AUTHOR]

Sb release characteristics of blast furnace slag, mining waste rock and tailing sand were investigated in static immersion and dynamic leaching test. These three kinds of waste samples were collected from the antimony mine in Lengshuijiang, China, produced in mining smelting process. Effects of solid/liquid ratio, sample size and pH of leaching solution on Sb release characteristics were inspected based on the analysis of scanning electron microscope, pH and EC of leachate. The optimal parameters for Sb leaching of each sample were analyzed. For blast furnace slag and mining waste rock, Sb release contents increased along with the decline of solid/liquid ratio. The maximum accumulative release contents were 42.13, 34.26 mg/kg at the solid/liquid ratio of 1:20. While Sb release content for tailing sand decreased first and then increased with the reduction of solid/liquid ratio. When the solid/liquid ratio was 1:5, the accumulative Sb release content reached the most (24.30 mg/kg). Sb release content of mining waste rock increased with the drop of leaching solution pH, with the highest accumulative release content of 26.01 mg/kg at pH 2.0. Sb release contents of blast furnace slag and tailing sand showed positive correlation with the variation of leaching solution pH. The maximum accumulative release contents of these two samples were 215.91 and 147.83 mg/kg, respectively, when leaching solution pH was 7.0. In summary, Sb release capacity of the three samples in descending order was tailing sand, blast furnace slag and mining waste rock. pH and EC of the leachate in dynamic test varied independently with the initial pH of leaching solution while showing close relationship with mineral hydrolysis in the waste. [ABSTRACT FROM AUTHOR]