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The release of metals from a mine tailings pond to groundwater is an important pathway to assess the environmental impact of mining residues and implications for wider environmental risk. We research the impact of manganese ore area in Heling Town, Xiangtan City, Hunan Province, central China. The focus is to assess the migration of manganese (Mn) using the Visual MODFLOW model of groundwater flow and the MT3DMS software platform to model solute transport. The modelling objective focuses on evaluating the migration of the pollution plume of manganese over a 20 year time period. The results show the sustained release and transport of Mn from the tailing pond. The concentration of Mn in the central pollution halo is 1.97 mg/L, and the maximum detectable range is at 2291 m, with the concentration range exceeding the third level of national groundwater standard is 1280 m. The result provides a basis for the development and utilization of the mining area and the pollution prediction and protection of the tailings pond. [ABSTRACT FROM AUTHOR]

Since waste residues of antimony ores are piled in a disorderly way long-term, heavy metal elements of the residues are dissolved and precipitated under the eluviation effect of snow and rain, causing serious pollution to the surrounding soil. This paper takes the antimony ore of Hunan stannary as the research area, and the surrounding soil of the storage yard of antimony ores as the research object, and carries out research on the migration rules of Sb in the leachate of waste residues of antimony ores in soil by means of spot sampling, lab analysis, and test and simulation, and simulates the migration of Sb in the surrounding soil of mining areas. The results show that through the dynamic penetration experiment of indoor soil columns, the hydrodynamic dispersion coefficient (D = 2.485 cm2 /h), adsorption distribution coefficient (Kd = 48.826 cm3/g), retardation factor (Rd = 78.50), and other parameters of Sb migrating in soil are obtained; the study makes use of the HYDRUS-1D model to conduct dynamic simulation of Sb in the soil nearby the antimony mine areas on the stannaries of Hunan Province, and the results indicate that the measured value is quite close to the fitted value, and in the correlation analysis of double variables, R is equal to 0.986, indicating that the simulation effect is fairly good. This study aims to provide a theoretical foundation and scientific basis for evaluating, controlling, curbing, and repairing the surrounding ecological environment of antimony mine areas. [ABSTRACT FROM AUTHOR]

Antimony ore tailings slag was used analyze heavy metals, chemical speciation, and leaching characteristics. The results show that the residual silicate phases account for 65.44% of Sb, 77.22% of As, 87.94% of Hg, 58.53% of Pb, 71.27% of Cd, and 96.34% of Zn. Although the exchangeable and carbonate phases account for 7.71% of Sb, 0.71% of As, 3.77% of Hg, 4.82% of Pb, 1.83% of Cd, and 1.73% of Zn, the water-or-acid-soluble phases contribute more to the chemical speciation of heavy metals. Concentrations of Sb, As, and Hg in the leachates increased with increasing solid-liquid ratio, decreasing particle size and increasing temperature. In simulated rainfall conditions, the total quantity increased in the order Sb > As > Hg and were 42.508 mg, 52.940 μg, and 0.876 μg, respectively, at 500 g antimony ore tailings. Under different rainfall intensity simulations, the maximum quantity in the leachates of Sb, As, and Hg were 93.894 mg, 255.451 μg, and 1.690 μg, respectively, and increased in the order of moderate > heavy > rainstorm. Finally, the cumulative leaching of Sb at pH 6.0 is 42.025 mg/L (higher than at 4.0 and 5.0), and the As and Hg at pH 4.0 are 107.097 μg/L and 0.989 μg/L, respectively. [ABSTRACT FROM AUTHOR]

A cubic crystal form Co3O4 was synthesized using the sol-gel method and applied as catalyst in the visible light-driven photocatalytic degradation of 1,2,4-trichlorobenzene (1,2,4-TCB). 1,2,4-TCB removal efficiency initially increased and was followed by a gentle decrease as the Co3O4 dosage increased, with the optimal dosage of 2.0 g/L. The degradation rate changed positively with light intensity and reaction temperature. However, pH exerted only a slight effect on 1,2,4-TCB degradation. Strong acidic and basic conditions were conducive to the photocatalytic degradation of 1,2,4-TCB. The optimal parameters for the photocatalytic degradation of 1,2,4-TCB were found at a Co3O4 dosage of 2.0 g/L, 350 W of illumination intensity, initial 1,2,4-TCB concentration of 7.5 mg/L at 30ºC, with 1,2,4-TCB removal efficiency of 90.13% after 6.0 hours photocatalytic degradation. The Co3O4 synthesized in the study with high-purity and stable properties guaranteed its high catalytic activity and stability. The possible mechanisms of visible light-driven photocatalytic degradation of 1,2,4-TCB with synthesized Co3O4 photocatalyst were also proposed. [ABSTRACT FROM AUTHOR]

The prediction of heavy metal pollution load at the soil-water interface of a mining area was studied through an improved soil and water assessment tool (SWAT) model. The Red Flag Mining Area of Xiangtan Manganese Mine in Hunan Province, China, was selected as the research district. GPS, ARCGIS, RS technology, and field experiments were employed in this study. A modified one-dimensional migration model was embedded in the sediment migration source module of SWAT in order to establish an Improved SWAT model for the prediction of manganese pollution load at the soil-water interface. The key pollution areas identified by the improved model were consistent with actual mine pollution, with the Nash-Sutcliffe efficiency Ens and regression R² coefficients of 0.88 and 0.91, respectively. The tudy would provide the theoretical foundation and scientific basis for management and repair at the site. [ABSTRACT FROM AUTHOR]

In this study, adsorption behaviors and mechanisms of Sb(III) ions onto Fe(III)-treated humus sludge adsorbent (FTHSA) from aqueous solutions was investigated using batch adsorption techniques, Fourier transform infrared (FT-IR) spectra and scanning electron microscopy were coupled to an energy-dispersive spectrometer (EDS). FTHSA was prepared via immersion with 1 mol/L FeCl3. The effects of dosage, contact time, Sb(III) initial concentration, and pH on the adsorption of Sb(III) onto FTHSA were investigated. Sb(III) adsorption was favored at pH with 2.0 and decreased dramatically with increasing pH. The description of equilibrium data of Sb(III) adsorption by Langmuir, Freundlich, and Dubbin-Radushkevich isotherm models showed that Langmuir model provided the best fit for Sb(III) adsorption with maximum adsorption amount of 9.433 mg/g. Pseudo first-order, pseudo second-order, Elovich, and intraparticle diffusion model were applied to describe the adsorption process of Sb(III) ions onto FTHSA. The results showed that the pseudo second-order model described well how Sb(III) adsorption and chemical adsorption played a dominant role in the adsorption process. The FT-IR spectra also indicated that the chemical interactions as ion exchange among the metal ions and N-H, O-H, C=O, COO, and C-O were mainly involved in the adsorption process. Therefore, FTHSA has a suitable potential removal for Sb(III) ions in the practical process. [ABSTRACT FROM AUTHOR]