WATER RESEARCH
·
2021
·
IF 11.236
Shuai Wang,Kai Zheng,Heping Li,Xiaonan Feng,Luying Wang,Qingyou Liu
Arsenopyrite is a common metal sulfide mineral and weathers readily in the open environment, releases As, and pollutes the surrounding environment. Humic acid (HA) is ubiquitous in soils, sediments and waters, and contains various functional groups and complex with arsenic, iron and other metal ions that affect the weathering behavior of arsenopyrite. Because As, iron, and HA are redox-active compounds, electrochemical techniques, including polarization curves, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), were used to fundamentally investigate the weathering process and mechanism of arsenopyrite over a wide range of environmental relevant conditions. Polarization curves showed higher HA concentrations (0-1000 mg•L −1 ), higher temperatures (5-35°C) or acidities (pH 1.0-7.0) promoted arsenopyrite weathering; there was a linear relationship between the corrosion current density ( i corr ), temperature (T) and acidity (pH): i corr = -3691.2/ T + 13.942 and i corr = -0.2445pH + 2.2125, respectively. Arsenopyrite weathering readily occurred in the presence of HA as confirmed by its activation energy of 24.1 kJ•mol −1 , and EIS measurements confirmed that the kinetics were controlled by surface reaction as confirmed by decreased double layer resistance. CV and surface characterization (FTIR and XPS) showed that arsenopyrite initially oxidized to S 0 , As(III) and Fe 2+ , then S 0 and Fe 2+ were ultimately converted into SO 4 2− and Fe 3+ , while As(III) oxidized to As(V). Furthermore, the carboxyl (–COOH) and phenolic (–OH) of HA could bind with As(III)/(V) and Fe 3+ via a ligand exchange mechanism forming As(III)/(V)-HA and As(III)/(V)-Fe-HA complexes that hinders the formation of FeAsO 4 and decreases the bioavailability of As. Findings gained from this study are valuable for the understanding of the fate and transport of As in acidic conditions, and have powerful implications for the remediation and management of As-bearing sites affected by mining activities.
研究领域:
环境科学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Shuxin Huang,Jian Feng,Junxia Yu,Yi Wang,Jiequan Liu,Ruan Chi,Haobo Hou
Release of the remaining ammonium salts from the weathered crust elution-deposited rare earth ore (WCE-DREO) would pose a serious threat to the environment. Thus, in this study, the adsorption and desorption performances of the WCE-DREO and four minerals that composed it were investigated to select an efficient eluent for the remained ammonium removal. Results showed that the ammonium ion adsorbed on the WCE-DREO and the clay minerals as a monolayer, and the calculated adsorption capacities were as follows: montmorillonite > WCE-DREO > halloysite > illite > kaolinite due to their different structure. pH experiment showed that it had great effects on ammonium adsorption on both the WCE-DREO and the investigated clays. Kinetic experiments showed that ammonium sorption and desorption process were both a fast process. Co-ions experiments showed that Mg 2+ showed the highest inhibition effect on the ammonium adsorption on the WCE-DREO due to its ionic character. Based on this data, magnesium salt was chosen as the eluent, and results showed that more than 93 % of the remaining ammonium ion could be removed from the WCE-DREO in the batch and column experiments.
研究领域:
环境科学
·
矿物学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Jackson Nkoh Nkoh,Ke-wei Li,Yang-xiao-xiao Shi,Jiu-yu Li,Ren-kou Xu
Phosphorus (P) availability in highly weathered soils is significantly influenced by the contents of iron (Fe)/aluminum (Al) oxides, clay minerals, and organic matter. With the increasing interest in biofertilizers (e.g. chitosan), it is important to understand how they affect P adsorption profiles on colloids of weathered soils rich in Fe/Al oxides. Thus, the effect of chitosan on the adsorption of P to colloids of hematite, gibbsite , Oxisol , and Ultisol was studied through electrokinetic measurements, spectroscopic analysis , and adsorption edge/isotherm profiles. The presence of chitosan significantly improved the surface positive charge and the decreasing trend of surface positive charge was slower for chitosan-treated colloids compared to the control with increasing pH. At pH 5.0, all the colloids were positively charged, with the oxides containing more positve charges than the soil colloids. At this pH value, the surface coverage capacity of P was 99.1, 61.6, 50.5, and 37.5 mmol kg⁻ 1 for Oxisol, Ultisol, hematite, and gibbsite, respectively. This suggests that clay minerals in soil colloids were vital in enhancing P adsorption. In the presence of chitosan, the surface coverage capacity of P was increased by 111%, 173%, 647%, and 488% for Oxisol, Ultisol, gibbsite, and hematite, respectively. Drawing inferences from spectroscopic analysis, citric acid desorption profile, and zeta potential analysis, we suggest that chitosan (CH) enhanced P adsorption by promoting the formation of (i) citric acid “undisplaceable” inner-sphere P complexes such as [Colloid-OP- O -CH] and [Colloid-OP- N -CH] , (ii) citric acid “displaceable” outer-sphere P complexes such as {[Colloid- O -CH]-OP} and {[Colloid- N -CH]-OP} , and (iii) water “leachable or soluble” P complexes such as {[Colloid-CH] + PO 4 ³⁻} and {[Colloid-OP]⁻CH + } . Thus, applying chitosan as a biofertilizer (source of N) along with P in highly weathered soils could improve P availability while reducing P leaching .
研究领域:
土壤学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
STUDIES IN CONSERVATION
·
2023
·
IF 0.8
Dan Li,Feigao Xu
The ability of hydroxyapatite (HAp)/collagen to consolidate tortoise shell relics was assessed. The chromatic parameters and hardness index of simulated weathered tortoise shells were measured before and after treatment to assess the effect of the application of HAp/collagen material. The HAp particles formed stable colloids under the proper conditions, and their average size was approximately 35 nm. SEM images showed that the HAp/collagen material was effective at filling and bonding the openings of the weathered tortoise shell. Compared with the control materials HAp and DAP/Ca(OH)2, HAp/collagen exhibited the best ability to consolidate simulated weathered tortoise shells. These results suggest a promising new and compatible method for the preservation of tortoise shell relics.
研究领域:
文物保护
·
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 12
·126401
·
IF 1.929
Jianrui Zha,Shuya Wei,Huarui Han,Feng Wang,Qinlin Ma
Calcium oxalate film was prepared by a novel two-step method on the surface of the marble substrate. The seed film was coated by a chemical reaction process, providing a good connection to the marble surface. Meanwhile, calcium oxalate solution was interwoven into the seed film to form a continuous network at room temperature. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results indicated that the calcium oxalate film prepared by the two-step method showed a more intensive crystallinity degree and homogenous than that by the traditional oxalate treatment method (a scattered seed film). Subsequently, it was found such calcium oxalate film is feasible for preventing the marble substrate from chemical weathering. Furthermore, the change of the chromatic value, water absorption properties and adhesion strength of the marble substrates by the film is minimal. This method overcomes the limitations of traditional oxalate treatment process and has great potential for the protection of marble artifacts.
研究领域:
材料科学
·
文物保护
✓ 已验证
DOI
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2018
·
IF 3.974
Qingyou Liu,Heping Li,Guoheng Jin,Kai Zheng,Luying Wang
Galena weathering often occurs in nature and releases metal ions during the process. Humic acid (HA), a critical particle of natural organic matter, binds metal ions, thus affecting metal transfer and transformation. In this work, an electrochemical method combined with spectroscopic techniques was adopted to investigate the interfacial processes involved in galena weathering under acidic and alkaline conditions, as well as in the presence of HA. The results show that the initial step of galena weathering involved the transformation Pb 2+ and S°, regardless of whether the solution was acidic or alkaline. Under acidic conditions, S° and Pb 2+ further transform into anglesite, and HA adsorbs on the galena surface, inhibiting the transformation of sulfur. HA and Pb (II) ions form bridging complexes. Under alkaline conditions without HA, the sulfur produced undergoes no transformation, whereas Pb 2+ will transform into PbO. The presence of HA changes the galena weathering mechanism via ionization effect, and Pb 2+ is ultimately converted into anglesite. Higher acidity in acidic conditions or higher alkalinity in alkaline conditions causes galena corrosion when the electrolyte does not contain HA. Conversely, higher pH always accelerates galena corrosion when the electrolyte contains HA, whether the electrolyte is acidic or alkaline. At the same acidity/alkalinity, increasing the concentration of HA inhibits galena weathering. Galena will release 134.7 g m −2 ·y −1 Pb 2+ to solution at pH 2.5, and the amount decreases to 28.09 g m −2 ·y −1 in the presence of 1000 mg/L HA. This study provides an in situ electrochemical method for the assessment of galena weathering.
研究领域:
地球化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MARINE POLLUTION BULLETIN
·
2021
·
IF 5.553
Huixin Du,Hongzhu Ma,Baoshan Xing
Here, naturally weathering plastics were collected and identified to understand the effect of the weathering conditions on their properties. The adsorption and desorption of crystal Violet (CV), a candidate of cationic organic pollutant , on microplastics (MPs) under various environmental conditions were simultaneously explored. The first type was the aged polyethylene (PE-MPs), which exhibited a fibrous structure with a smoother and uniform surface attached some flaps, while the second type was recognized as the aged polypropylene (PP-MPs), which showed a lamellar structure with less smooth and distorted texture surface attached with fragments and small grains. The experiment data fitted well with the pseudo-second-order kinetic and Freundlich isotherm models. The possible interactions between CV and MPs included electrostatic attraction, hydrogen bonding and hydrophobic interactions. This study demonstrates that the high possibility of transport ionic pollutants from fresh water to ocean by the naturally weathering microplastics, highlighting their potential risk in various environments.
研究领域:
环境科学
·
生态学
✓ 已验证
DOI
高影响因子
Minerals
·
2024
·Vol. 14
·期 4
·360
·
IF 2.2
Gaofeng Wang,Bowen Ling,Xiaoliang Liang,Jie Xu,Shichang Kang,Jingming Wei,Wei Tan,Runliang Zhu,Jianxi Zhu,Hongping He
Electrokinetic mining (EKM) is a novel method for rare earth element (REE) mining that can achieve green and efficient recovery of REEs. However, as yet, there is no accurate model for describing the electrokinetic transport of REEs in weathering crusts, and this hinders the wider application of EKM. The conventional model fails to capture the microscale transport physics occurring in the nanochannels that exist ubiquitously in weathering crusts. Consequently, the existing models cannot distinguish the mobilities of different REEs. Here, we report a new model for a more faithful description of the electrokinetic transport of REEs in weathering crusts that considers the ionic size, which has previously been neglected. We reveal that the electrokinetic transport of heavy REEs (HREEs) is faster than that of light REEs (LREEs) in weathering crusts, which is contrary to the predictions of conventional models. Our model was validated experimentally by measurements of the electrokinetic transport of two LREEs (La and Sm) and an HREE (Er) in weathering crusts. The speed of electrokinetic transport follows the order Er > Sm > La. Our findings suggest that the ionic size is a non-negligible factor affecting the electrokinetic transport of REEs in weathering crusts containing nanochannels. This work offers a constitutive model to describe the electrokinetic transport of REEs in weathering crusts, which promotes both theoretical developments and practical applications of EKM.
研究领域:
环境科学
·
矿物工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2022
·
IF 5.479
Fang Zhou,YiXin Zhang,Qi Liu,Suhua Huang,Xiaoyan Wu,Zhiwei Wang,Lisen Zhang,Ruan Chi
Weathered crust elution-deposited rare earth ores tailings are mainly composed of clay minerals, which can be used as efficient adsorption materials. In order to explore the possibility of recovering rare earth ions using tailings from mine waste liquid, the weathered crust elution-deposited rare earth ores tailings were modified to adsorb La 3+ and Y 3+ with respect to initial concentrations of La 3+ and Y 3+ , temperatures and impurity ions, and the adsorption kinetics and thermodynamics were further discussed to analyze the adsorption behavior. The results show a higher adsorption capacity of heavy rare earth Y 3+ than that of light rare earth La 3+ . The presence of impurity ions does not adversely affect adsorption of rare earth ions by the modified tailings. The adsorption performance is well fitted with the Langmuir adsorption isotherm model rather than the Freundlich adsorption isotherm model, and the maximum adsorption capacity is 0.0226 mmol/g and 0.0197 mmol/g for Y 3+ and La 3+ , respectively. Pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich model were applied to fit the adsorption results. The results show that the adsorption process of modified tailings for La 3+ and Y 3+ is more in line with the pseudo-second-order kinetic model, suggesting the dominated chemical adsorption. The adsorption activation energies of La 3+ and Y 3+ on modified tailings are 11.60 KJ/mol and 7.60 KJ/mol, respectively. Thermodynamic studies show that the adsorption process of modified tailings for La 3+ and Y 3+ is a spontaneous endothermic reaction in the experimental temperature range. The recovery of rare earth ions form the modified tailings can be carried out by the leaching solution of weathered crust elution-deposited rare earth ores, 0.2 mol/L (NH 4 ) 2 SO 4 solution. In addition, the modified tailings are reversible and keep functionality to reuse in several cycles after elution process.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2024
·
IF 5.2
Aoyang Sha,Huifang Yang,Meiling Jiang,Zhengyan He,Zhenhu Liu,Zhigao Xu,Yaguang Du,Wu Ming,Ru'an Chi
Weathered crust elution-deposited rare earth ores (WREOs) are rich in medium and heavy rare earth. In order to improve the in-situ leaching process, which is prone to landslides and poor permeability, cationic hydroxyethyl cellulose (PQ-10) was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate ((NH 4 ) 2 SO 4 ) to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion. Adding PQ-10 can inhibit the hydration swelling of WREOs, promote the percolation effect of the leaching agent, improve the rare earth (RE) leaching efficiency, and reduce the impurity aluminum (Al) leaching efficiency. Compared with the conventional leaching agent 2 wt% (NH 4 ) 2 SO 4 , the percolation time is reduced by 50% by using the composite leaching agent (0.02 wt% PQ-10+2 wt% (NH 4 ) 2 SO 4 ). PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups, which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding, weakening the electrostatic repulsion between mineral particles, reducing the WREOs interlayer spacing, compressing the double electric layer thickness at the solid-liquid interface, weakening the mineral hydration swelling and increasing the percolation rate. The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them, increasing their particle size and reducing their hydration dispersion, and preventing blockage of the percolation pores caused by migration of the fine particles through the ore body with the solution. PQ-10 molecules also insert the mineral interlayer and expulsion of the internal water, further inhibiting the swelling of WREOs. Adding PQ-10 reduces the surface tension of (NH 4 ) 2 SO 4 solution, improving the spreading and spreading ability of the solution, reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor. It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs. In addition, PQ-10 expands the leaching pore size and seepage channels, further improving the percolation rate.
研究领域:
矿物学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2019
·
IF 5.714
Kai Zheng,Heping Li,Liping Xu,Shengbin Li,Luying Wang,Xiaoying Wen,Qingyou Liu
Pyrite weathering often occurs in nature and causes heavy metal ion pollution and acid mine drainage during the process. Humic acid (HA) is a critical natural organic material that can bind metal ions, thus affecting metal transfer and transformation. In this work, in situ electrochemical techniques combined with spectroscopic analysis were adopted to investigate the interfacial processes involved in pyrite weathering with/without HA. The results showed that the pyrite weathering mechanism with/without HA is FeS 2 → Fe 2+ + 2S 0 + 2e − . The presence of HA did not change the pyrite weathering mechanism, but HA adsorbs on the pyrite surface and inhibits the further transformation of sulfur. Furthermore, HA and Fe(II) ions can form complex at 45.0 °C. Increased concentration of HA, decreased HA solution acidity or decreased environmental temperature would all weaken the pyrite weathering, for the above conditions cause pyrite weathering to have a larger resistance of the double layer and a larger passive film resistance. Pyrite will release 73.7 g m −2 ·y −1 Fe 2+ to solution at pH 4.5, and the amount decreases to 36.8 g m −2 ·y −1 in the presence of 100 mg/L HA. This study provides an in situ electrochemical method for the assessment of pyrite weathering.
研究领域:
环境科学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ARCHAEOMETRY
·
2021
·Vol. 64
·期 4
·997-1012
·
IF 1.886
Lina Xie,Xue-Qiang Chen,Bingjian Zhang,Yulan Hu
The consolidation of weathered sandstone has been an important subject in cultural heritage conservation. Due to the loss of cementing materials, the structure of sandstone becomes loose, thus mechanical strength decreases dramatically. To restore cohesion between sand grains, a novel nano-MgO-based consolidant (MMH dispersion) is studied. In this paper, the MMH dispersions with different concentrations and number of applications are applied on artificial weathered sandstone specimen with trickling infiltration treatment to select the optimal consolidation method. The consolidation products that formed in the pores between sand grains are characterized through XRD analysis and SEM observation. The effectiveness of consolidation treatment is evaluated in terms of mechanical properties (i.e., compressive strength and surface hardness) and compatibility (i.e., color variation and capillary water absorption). Due to the formation of 5 Mg(OH) 2 ·MgCl 2 ·8H 2 O, sand grains are more effectively bonded. Therefore, the treated specimens experience a significant improvement in mechanical strength. Finally, the specimens are subjected to a salt crystallization test, the results of which show that the MMH consolidant increased the durability of the specimens. After treatment, the intermediate concentration of MMH consolidant with five applications reveals the best potential to act as a promising consolidation method for the conservation of the weathered sandstone.
研究领域:
文物保护
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）