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1

Visible light-driven photocatalytic degradation of 1,2,4-trichlorobenzene with synthesized Co3O4 photocatalyst

100%

Wang C. , Ren B.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 5

EN

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.

2

Antimony ore tailings: heavy metals, chemical speciation, andleaching characteristics

80%

Zhou Y. , Ren B. , Hursthouse A. S. , Zhou S.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 1

EN

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.

3

Release law of Sb, As, and Hg in antimony smelting slag under simulated acid rain

80%

Zhou S. , Li N. , Ren B. , Zhang P.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 2

EN

This study takes the Southern antimony smelting slag depot in Xikuangshan (XKS) Sb mine in the city of Lengshuijiang, Hunan, China, as the research object and explores the release law of Sb, As, and Hg in smelting slag under different pH-value simulated acid rain by a semi-dynamic leaching experiment of simulating the local rain. The results show that the leachate pH value is positively correlated with the pH value of simulated acid rain, while the leachate conductivity is negatively correlated with it. The leaching rates of As and Hg are negatively correlated with the pH value of the simulated acid rain, while the leaching rate of Sb is positively correlated with it; in the leaching process, the leachate pH value goes downward slowly after shooting up, but the leachate conductivity is continuously reduced; the releasing process of Sb, As, and Hg consists of two stages, and their leaching rate forms such an order as Sb > Hg > As. The diffraction peak intensity of the main mineral composition of quartz and calcite decreases significantly after leaching; the smelting slag’s surface becomes less rough than before leaching, with fewer pores and edges, and the contents of S, Si, Al, Fe, Ca, and Sb on the slag surface decrease while the content of O, As, and Hg increases.

4

Study on the migration rules of Sb in antimony ore soil based on HYDRUS-1D

70%

Zhang Y. , Ren B. , Hursthouse A. S. , Deng R. , Hou B.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 2

EN

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.

5

Leaching and releasing characteristics and regularities of Sb and As from antimony mining waste rocks

70%

Zhang Y. , Ren B. , Hursthouse A. , Deng R. , Hou B.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 5

EN

This study collected waste rock samples during antimony mining and then probed into the releasing characteristics and regularities of heavy metals Sb and As under different factors (solid-to-liquid ratio, particle size, temperature, agitation intensity, pH value of leaching solution and leaching intensity) through indoor static soaking and dynamic leaching experiment. The results showed that: the smaller solid-to-liquid ratio, smaller particle size, or higher soaking liquid temperature could achieve the faster dissolution and precipitation rate of heavy metals; agitation could accelerate the dissolution and precipitation of heavy metals; the lower pH value could help to obtain more heavy metals deposited; the higher leaching intensity could make the rate of heavy metal reach the precipitation peak faster. Meanwhile, an equation fitting was conducted to the changing situation of Sb and As precipitation amount from antimony waste rocks with different influence factors under static and dynamic leaching, and the fitting results were good. This study was to reveal the releasing characteristics of heavy metal Sb and As in antimony mining waste rocks, so as to promote the harmonious development of metal mines.

6

An improved SWAT for predicting manganese pollution load at the soil-water interface in a manganese mine area

70%

Zhang Y. , Ren B. , Hursthouse A. S. , Deng R. , Hou B.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 5

EN

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 study would provide the theoretical foundation and scientific basis for management and repair at the site.

7

Optimization and evaluation of alkali-pretreated Paeonia ostii seed coats as adsorbent for the removal of MB from aqueous solution

70%

Liu Q. , Li T. , Zhang S. , Qu L. , Ren B.

Polish Journal of Chemical Technology

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2018

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tom Vol. 20, nr 3

29--36

EN

A novel efficient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g–1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g–1 for MB at 25°C. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was influenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an efficient adsorbent to remove MB from solution.

8

Spatiotemporal variations of growing-season NDVI associated with climate change in northeastern China’s permafrost zone

61%

Gua J. , Hu Y. , Xiong Z. , Yan X. , Ren B. , Bu R.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 4

EN

Vegetation is an essential component of terrestrial ecosystems, and it plays an important role in regulating climate change, the carbon cycle, and energy exchange. And permafrost is extremely sensitive to climate change. In particular, aboveground vegetation on permafrost has great sensitivity to that change. The permafrost zone of northeastern China, within middle and high latitudes of the northern hemisphere, is the second-largest region of permafrost in China. It is at the southern edge of the Eurasian cryolithozone. This study analyzes growing-season spatiotemporal variation of the normalization difference vegetation index (NDVI) in this permafrost zone and the correlation between NDVI and climate variables during 1981-2014. Mean growing-season NDVI significantly increased by 0.0028 yr⁻¹ over the entire permafrost zone. The spatial dynamics of vegetation cover in the zone had strong heterogeneity on the pixel scale. Pixels that showed increasing trends accounted for 80% of the permafrost area, and were mostly found in the permafrost zone with the exception of western steppe regions. Pixels that showed decreasing trends (approximately 20% of the permafrost area) were mainly in the cultivated and steppe portions of the study area. Our results indicated that temperature was the dominant influence on vegetation growth during the growing season in most permafrost zones.

9

Parameter optimization of double-excess runoff generation model

61%

Ren B. , Liang J. , Yan B. , Lei X. , Fu W. , Ni. X. , Guo J.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 2

EN

Research on the optimization of hydrological model parameters is an important issue in the field of hydrological forecasts, as these parameters not only directly impact the accuracy of forecast programs, but also relate to the development, application, and popularization of hydrological models. In this paper we selected the double-excess runoff generation model as the subject for research, and the data obtained from tens of flooding events in the Fen River Basin were used for the construction of these models. The SCE-UA and MOSCDE algorithms were then taken to optimize the models’ parameters. The results showed that: as compared with the SCE-UA algorithm, higher flood forecast accuracies were obtained through model parameter optimization using the MOSCDE algorithm. During the examination period, the compliance rate of the flood peak magnitude increased from 60% to 70%, while the compliance rate of the flood peak duration increased from 80% to 90%. The Nash-Sutcliffe efficiency (NSE) of the flood peak magnitudes increased from 0.664 to 0.878, which demonstrates an improvement in goodness-of-fit; the RMSE value of flood peak magnitudes also decreased from 399.8 to 236.84, thus showing a decrease in dispersion and an improvement in goodness-of-fit. With the continuous improvements made in hydrological parameter algorithms and the creation of new optimization algorithms, there is no doubt that the optimization of hydrological model parameters will become more reasonable.

10

Land use regression modelsusing satellite aerosol optical depth observations and 3D building data from the central cities of Liaoning Province, China

51%

Gong J. , Hu Y. , Liu M. , Bu R. , Chang Y. , Bilal M. , Li C. , Wu W. , Ren B.

Polish Journal of Environmental Studies

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2016

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tom 25

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nr 3