Release Characteristics of Manganese in Soil under Ion-absorbed Rare Earth Mining Conditions

Liu, Zuwen; Lu, Chenbin; Shi, Yang; Zeng, Jinfeng; Yin, Shiyun

doi:10.1080/15320383.2020.1771273

Cited by 8 publications

(3 citation statements)

References 20 publications

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“…The XRD results showed that the main minerals of Cambisol were quartz, orthoclase, and kaolinite (Figure 4a) (Lu, 2020), and that acidification had a minor influence on phase transformation which mainly occurred at 2θ range of 20–30°, as indicated by raw subtracted XRD patterns (Figure 4b). The diffraction peak of orthoclase decreased whereas that of kaolinite and quartz increased with soaking time (Figure 4b), indicating that acidification induced, to some extent, the decomposition of primary minerals, accompanied by some phase transformation which might be associated with the reduction of Mn (III/IV) to Mn (II) oxides.…”

Section: Resultsmentioning

confidence: 98%

Manganese reduction regulates soil organic carbon loss from an acidified Cambisol

Zhou

Kong

Song

et al. 2022

European J Soil Science

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Soil acidification has occurred and accelerated in Jiaodong Peninsula, China, causing serious problems, such as manganese (Mn) toxicity and soil organic carbon (SOC) losses. However, the relationships between SOC and soil Mn are still unclear. This study aimed to explore the changes of Mn fractions and SOC under soaking conditions and the acidification‐induced positive coupled relationship between them. A sequential extraction for Mn species after acid soaking of a Cambisol was conducted, and the soil (pre‐ and post‐soaking) was characterised by X‐ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that acidification of a Cambisol (from pH 6.48 to pH 2.79) induced SOC losses (15.8% of initial SOC). Meanwhile, lower mobile or immobile Mn (especially oxide‐Mn) significantly decreased, accompanied by an increase in readily soluble Mn. It was further shown that the amount of decrease in free Mn reached 268.7 mg kg−1, accounting for 93.8% of the total loss of soil Mn, indicating that the reductive dissolution of amorphous Mn (III/IV) oxides is the dominant reaction in acidified Cambisols. This result was also supported by XRD and SEM. Correlation analysis showed that under soil acidification, the reductive dissolution of amorphous Mn (III/IV) oxides drove losses of both SOC and soil Mn. Therefore, a possible reaction mechanism was proposed: at neutral and alkaline pH, immobile complexes of Mn (III/IV) and particulate organic carbon (POC) formed; and, at acidic pH, readily mobile complexes of Mn (II) and dissolved organic carbon (DOC) formed. Our research suggested that Mn‐organic carbon complexes regulated the transport, transformation, and leaching of soil Mn and SOC, and future research should focus on the soil acidification‐driven Mn reduction‐carbon oxidation processes. Highlights Acidification accelerated soil organic carbon losses. Acidification induced reductive dissolution of amorphous Mn (III/IV) oxides. A positive couple relationship between SOC and soil Mn existed in acidified soils.

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Section: Resultsmentioning

confidence: 98%

Manganese reduction regulates soil organic carbon loss from an acidified Cambisol

Zhou

Kong

Song

et al. 2022

European J Soil Science

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“…Excessive amounts of heavy metals released by the geochemical cycle [1,2] and human production activities (domestic sewage [3], industrial production [4], mining [5,6]) pose a major threat to the ecological environment system and may have a negative impact on the health of humans, plants, and microorganisms [7,8]. At present, there is no effective degradation pathway for heavy metals in the water environment, and the most common method is centralized recovery treatment after adsorption and desorption [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

The Removal of Pb2+ from Aqueous Solution by Using Navel Orange Peel Biochar Supported Graphene Oxide: Characteristics, Response Surface Methodology, and Mechanism

Liu

Shi

Zhang

et al. 2022

IJERPH

Self Cite

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The value-added utilization of waste resources to synthesize functional materials is important to achieve the environmentally sustainable development. In this paper, the biochar supported graphene oxide (BGO) materials were prepared by using navel orange peel and natural graphite. The optimal adsorption parameters were analyzed by response surface methodology under the conditions of solution pH, adsorbent dosage, and rotating speed. The adsorption isotherm and kinetic model fitting experiments were carried out according to the optimal adsorption parameters, and the mechanism of BGO adsorption of Pb2+ was explained using Scanning Electron Microscope (SEM-EDS), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Compared with virgin biochar, the adsorption capacity of Pb2+ on biochar supported graphene oxide was significantly increased. The results of response surface methodology optimization design showed that the order of influence on adsorption of Pb2+ was solution pH > adsorbent dosage > rotating speed. The optimal conditions were as follows: solution pH was 4.97, rotating speed was 172.97 rpm, and adsorbent dosage was 0.086 g. In the adsorption–desorption experiment, the desorption efficiency ranged from 54.3 to 63.3%. The process of Pb2+ adsorption by BGO is spontaneous and endothermic, mainly through electrostatic interaction and surface complexation. It is a heterogeneous adsorption process with heterogeneous surface, including surface adsorption, external liquid film diffusion, and intra-particle diffusion.

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“…Numerous scholars (Bao et al 2008) have discovered that REEs attached to ion absorbed REM were easily desorbed through ion exchange when encountering with positive ions (such as Na+, NH 4 + and H + ). However, the leaching process of REM using ammonium sulfate in forms of the pool leaching, dump leaching and in-situ leaching (Liu et al 2014) might not only induced the release of associated toxic metals (Liu et al 2020), but also resulted in a series of environmental issues, such as copollution of associated toxic metals and REEs, soil fertility degradation, land deserti cation, headwater pollution and downstream farmland damage (Xie et al 2020, Feng et al 2012, Zhou et al 2015. Furthermore, these pollutants (ammonium nitrogen, associated toxic metals and REEs) remained in REM potentially polluted the surface water and groundwater through surface runoff and leakage, which posed serious health risks to humans (Huang et al 2009, Rao et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Accumulation and Distribution of Rare Earth Elements (REEs) and Non-REEs With Vetiver Grass in The Abandoned Ion-Absorbed Rare Earth Mine

Liang¹,

Cai²,

T³

et al. 2021

Preprint

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Overexploitation of rare earth elements (REEs) has caused serious desertification and environmental pollution, and ecological restoration of mines has attracted increasing national attention. In this paper, experiments involved land plowing, organic fertilizer broadcasting and vetiver cultivation were carried out to repair abandoned ion-absorbed rare earth mines (REM). Toxic metals content and pH in mining soil, distribution and transportation of toxic metals in the soil – vetiver grass system were investigated in detail.Results revealed that the abandoned REM soil was weakly acidic (pH=4.09) and rich in various toxic metals composed of REEs (La, Ce, Nd, Y, Gd, Dy) of 657.57mg/kg and Non-REEs (Pb, Cu, Se, As, Cd) of 109.98mg/kg. The distribution pattern in vetiver grass illustrated that toxic metals accumulation was mainly concentrated in the roots instead of shoot, and then the cumulative concentration of REEs in roots were much greater than that of Non-REEs. Furthermore, vetiver grass exhibited preferential accumulation of Cd, Se and REEs during the absorption process (from soil to root) and preferential accumulation of Pb, Cu and As during the translocation process (from root to leaf). The adsorption behavior of toxic metals by vetiver was confirmed due to these observed irregular particles in the scanning electron microscopy.

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Release Characteristics of Manganese in Soil under Ion-absorbed Rare Earth Mining Conditions

Cited by 8 publications

References 20 publications

Manganese reduction regulates soil organic carbon loss from an acidified Cambisol

Manganese reduction regulates soil organic carbon loss from an acidified Cambisol

The Removal of Pb2+ from Aqueous Solution by Using Navel Orange Peel Biochar Supported Graphene Oxide: Characteristics, Response Surface Methodology, and Mechanism

Accumulation and Distribution of Rare Earth Elements (REEs) and Non-REEs With Vetiver Grass in The Abandoned Ion-Absorbed Rare Earth Mine

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