ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2014
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IF 2.482
Xinghao Wang,Ruijuan Qu,Zhongbo Wei,Xi Yang,Zunyao Wang
Mercury (Hg) compounds are widely distributed toxic environmental and industrial pollutants and they may bring danger to growth and development of aquatic organisms. The distribution of Hg species in the 3 percent NaCl solution was calculated using the chemical equilibrium model Visual MINTEQ, which demonstrated that Hg was mainly complexed by chlorides in the pH range 5.0–9.0 and the proportions of HgCl 4 2− , HgCl 3 − and HgCl 2 (aq) reached to 95 percent of total Hg. Then the effects of cations (Ca 2+ , Mg 2+ , K + and H + ), anions (HCO 3 − , NO 3 − , SO 4 2− and HPO 4 2− ) and complexing agents (ethylene diamine tetraacetic acid (EDTA) and dissolved organic matter (DOM)) on Hg toxicity to Photobacterium phosphoreum were evaluated in standardized 15 min acute toxicity tests . The significant increase of 6.3-fold in EC 50 data with increasing pH was observed over the tested pH range of 5.0–8.0, which suggested the possible competition between hydroxyl and the negatively charged chloro-complex. By contrast, it was found that major cations (Ca 2+ , Mg 2+ and K + ) have little effect on Hg toxicity to P. phosphoreum . An interesting finding was that the addition of HPO 4 2− significantly increased Hg toxicity, which may imply that the addition of phosphate increased the soluble Hg–chloro complex species. Additions of complexing agents (EDTA and DOM) into the exposure water increased Hg bioavailability via complexation of Hg. Finally, a model which incorporated the effect of pH, HPO 4 2− , HCO 3 − , SO 4 2− and DOM on Hg toxicity was developed to predict acute Hg toxicity for P. phosphoreum , which may be a useful tool in setting realistic water quality criteria for different types of water.
研究领域:
环境生物学
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毒理学
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DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2021
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IF 5.909
Binliang Wang,Junli Zheng,Yingying Li,Adel Zaidi,Yiwei Hu,Baowei Hu
Exploitation of algal biochar is a profitable opportunity for the utilization of filamentous green algae due to its sustainable growth and ease of harvest. In this study, Rhizoclonium -derived biochar (CB) and δ-MnO 2 -modified biochar (MnO 2 /CB) were fabricated for uranium (U(VI)) removal. The results showed that the δ-MnO 2 modification increased the BET surface area and decreased the isoelectric point. The maximum sorption amount of U(VI) by the MnO 2 /CB reached up to 100.2 mg/g (pH = 6.0, 289 K, and 0.01 M NaCl), which was two times higher than that of the CB. After five consecutive sorption/desorption cycles, the affinity of the MnO 2 /CB for U(VI) maintained in 94.8%. According to the analysis of X-ray photoelectron spectroscopy, it confirmed that the U(VI) sorption was mainly ascribed to the surface complexation between U(VI) and oxygen-containing functional groups on the surface of the MnO 2 /CB. Therefore, this investigation not only encourages the development of algal biochar derived from the filamentous green algae but also provides a novel adsorbent for U(VI) removal from aqueous solutions.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Metals
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2021
·Vol. 11
·期 6
·919
·
IF 2.351
Feng Feng,Jiamei Liu,Mingxing Zhao,Lu Yu,Haixin Wang,Chunshan Lu,Qunfeng Zhang,Jia Zhao,Yanxia Sun,Jie Cen,Xiaonian Li
Gold as a precious metal resource has high recycling significance. However, the current extraction methods cannot achieve the both efficiency and environmental friendliness. In this paper, we propose a new gold leaching agent, which can leach gold under light condition by mixing iodoform (CHI3) with 1-butyl-3-methylimidazolium dicyanamide (BmimN(CN)2) ionic liquid. Under 25 °C and 13 W incandescent lamp irradiation, the leaching yield of gold can achieve 100 wt%, and the average leaching rate is 945 mg Au/(h·mol·CHI3) (18.9 times of that of the cyanidation method). Through the analysis of the results of radical inhibition experiment, UV-Vis and XPS, a possible leaching mechanism is proposed: the iodine radical generated by light oxidizes Au0to Au+, and then forms AuN(CN)2by coordinating with N(CN)2−. Subsequently, the ionic liquid and Au N(CN)2form a stable [Bmim]·[Au(N(CN)2)2] ion pair structure, further promoting the dissolution reaction. The leaching yield of gold can reach 81.9 wt% and 100 wt%, respectively, when applied to ore and waste electrical and electronic equipment (WEEE); the leaching yield of gold can also reach 100 wt% when applied to a waste catalyst by adding a Soxhlet extraction. The results show that this method is not only efficient, mild, and environmentally friendly, but also has strong adaptability and wide application prospects.Keywords:gold recovery;ionic liquid;free radical;waste catalyst;oxidation-complexation
研究领域:
化学
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环境科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Pengfei Qi,Rong Luo,Thomas Pichler,Jianqiang Zeng,Yan Wang,Yuhua Fan,Kunyan Sui
Removal of trivalent species of As and Sb from wastewater is crucial due to their more toxic and mobile properties. In this study, a novel magnetic core-shell microsphere Fe 3 O 4 @TA@UiO-66 was developed via in-situ crystal growth of UiO-66 around the magnetic Fe 3 O 4 modified by Tannic Acid (TA). Characterization of the microsphere by transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD) confirmed that UiO-66 was adhered on the surface of Fe 3 O 4 functionalized by TA. Adsorption experiments showed that the magnetic Fe 3 O 4 @TA@UiO-66 had high adsorption capacity for As(III) and Sb(III) and could be rapidly separated from aqueous media within two minutes after treatment. The adsorption kinetics and adsorption isotherms were described well by the pesudo-second order model and Langmuir model, respectively. In addition, the composite exhibited excellent removal performance for As(III) and Sb(III) in a broad solution chemistry environment, including pH and co-existing anions. Based on X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) measurement, we proposed that the removal mechanism was mainly controlled through a synergistic interaction of surface complexation and hydrogen bonding. This study indicates the potential of the magnetic microsphere to be used as an effective material for the removal of As(III) and Sb(III) from water.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
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2015
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IF 2.711
Shu-Cui Ma,Ji-Lin Zhang,De-Hui Sun,Gui-Xia Liu
Removal of noxious heavy metal ions (e.g. Pb(II)) by surface adsorption of minerals (e.g. diatomite) is an important means in the environmental aqueous pollution control. Thus, it is very essential to understand the surface adsorptive behavior and mechanism. In this work, the Pb(II) apparent surface complexation reaction equilibrium constants on the calcined diatomite and distributions of Pb(II) surface species were investigated through modeling calculations of Pb(II) based on diffuse double layer model (DLM) with three amphoteric sites. Batch experiments were used to study the adsorption of Pb(II) onto the calcined diatomite as a function of pH (3.0–7.0) and different ionic strengths (0.05 and 0.1 mol L −1 NaCl) under ambient atmosphere. Adsorption of Pb(II) can be well described by Freundlich isotherm models. The apparent surface complexation equilibrium constants (log K ) were obtained by fitting the batch experimental data using the PEST 13.0 together with PHREEQC 3.1.2 codes and there is good agreement between measured and predicted data. Distribution of Pb(II) surface species on the diatomite calculated by PHREEQC 3.1.2 program indicates that the impurity cations (e.g. Al 3+ , Fe 3+ , etc.) in the diatomite play a leading role in the Pb(II) adsorption and dominant formation of complexes and additional electrostatic interaction are the main adsorption mechanism of Pb(II) on the diatomite under weak acidic conditions.
研究领域:
环境科学
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化学
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产品关联
DOI
高影响因子
MINERALS ENGINEERING
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2022
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IF 5.479
Xinzhuang Fu,Ya Gao,Haisheng Han,Zhiyong Gao,Li Wang,Wei Sun,Tong Yue
The deep integration of modern information technology and mineral processing, the establishment and application of a database, and fast, efficient and accurate selection of beneficiation technology and flotation reagent system, which is a development trend of modern mineral processing. In this study, the flotation system with hematite, quartz and dodecylamine (DDA) as collector was used as an example to quantify the types and densities of active sites on the surfaces of hematite and quartz, as well as the reaction equilibrium constants of their hydration reactions and the adsorption equilibrium constants of DDA. Protonation and adsorption experiments were simulated using the Surface complexation model (SCM) with single site ( ≡SiOH or ≡FeOH ) and monodentate surface complexation. The protonation and adsorption reaction equations were established based on the material and charge equilibrium under experimental conditions, and the equilibrium constants of the surface reactions were obtained by numerical optimization. Results of surface complexation model indicate that the adsorption ability of DDA on the quartz surface is stronger than that of hematite. DDA adsorption can be successfully predicted using SCM in pH and different mineral ratios system. Overall, this work reveals the quantitative expression of the mineral inherent characteristic and the affinity with reagents, forming a model for predicting the adsorption capacity of the reagent and providing an optimal solution for flotation.
研究领域:
矿物加工工程
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物理化学
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DOI
高影响因子
MOLECULES
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2022
·Vol. 27
·期 11
·3395
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IF 4.927
Changli Ma,Taisen Zuo,Zehua Han,Yuqing Li,Sabrina Gärtner,Huaican Chen,Wen Yin,Charles C. Han,He Cheng
The atomic picture of cellulose dissolution in alkali/urea aqueous solution is still not clear. To reveal it, we use trehalose as the model molecule and total scattering as the main tool. Three kinds of alkali solution, i.e., LiOH, NaOH and KOH are compared. The most probable all-atom structures of the solution are thus obtained. The hydration shell of trehalose has a layered structure. The smaller alkali ions can penetrate into the glucose rings around oxygen atoms to form the first hydration layer. The larger urea molecules interact with hydroxide groups to form complexations. Then, the electronegative complexation can form the second hydration layer around alkali ions via electrostatic interaction. Therefore, the solubility of alkali aqueous solution for cellulose decreases with the alkali cation radius, i.e., LiOH > NaOH > KOH. Our findings are helpful for designing better green solvents for cellulose.Keywords:neutron total scattering;cellulose;dissolution mechanism;layered structure;complexation
研究领域:
化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
·
IF 14.224
Shiwei Xie,Chang Li,Hui Zhan,Wei Shao,Yuanxin Zhao,Peng Liu,Peng Liao
Fe-based replacement and precipitation are promising methods for removal of copper ethylenediaminetetraacetic acid (Cu(II)-EDTA) but are limited by the necessity of controlling pH and dissolved oxygen. The details of the decomplexation mechanism also remain unclear. The present work investigated an anoxic iron electrocoagulation process capable of automatically modulating anoxic conditions and solution pH during exposure to air and thus promoting the rapid and thorough decomplexation of Cu(II)-EDTA. Dissolved Fe (II), rather than Fe(II)-bearing minerals, was found to be primarily responsible for the reduction of Cu(II)-EDTA to Cu(I)-EDTA and for the subsequent replacement reaction to generate free Cu(I) ions within the initial pH range of 2–7. The Cu(I) was primarily precipitated as Cu 2 O on the surface of green rust and magnetite as the pH was increased. The aeration of these Fe-containing precipitates released free Cu(I) ions instead of chelated Cu into solution, allowing for recycling of the Cu. This release of Cu(I) was likely induced by the pH decrease during aeration. This study provides important insights regarding the reductive decomplexation of chelated Cu(II) and the recovery of Cu via anoxic iron electrocoagulation, which is a promising green approach to recycling Cu from wastewater.
研究领域:
环境科学
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废水处理
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DOI
PubMed
高影响因子
WATER RESEARCH
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2022
·
IF 13.4
Siqi Liu,Andrey M. Kuznetsov,Weiqing Han,Alexei N. Masliy,Gregory V. Korshin
Methylated arsenic species are ubiquitous in the environment and resistant to removal by conventional treatment technologies. This study addressed this challenge based on the examination of the removal of dimethylarsinic acid (DMA) in a system that combines zerovalent iron (ZVI) and powdered activated carbon (PAC). The removal of DMA in the ZVI/PAC system was compared to that by coagulation, adsorption, electrochemical and Fenton oxidations, and other conventional methods. While only the electrochemical oxidation using a PbO 2 /Sb-SnO 2 /Ti anode allowed removing up to 60% DMA at several hours-long treatment times, the removal of DMA in the ZVI/PAC system containing 10 g/L ZVI and 2.5 g/L PAC with an initial pH of 2.0 was 95% for a 30 min reaction time. Specific roles of PAC, ZVI and its oxidation products in DMA removal were examined based on the spectroscopic data and quantum chemical modeling for the DMA/Fe(II) and DMA/Fe(III) systems. These methods demonstrated the formation of moderately strong DMA/Fe(II) and DMA/Fe(III) complexation. These results and relevant kinetic data were interpreted to indicate that the removal of DMA is governed by the rapid generation of Fe 2+ ions released as a result of accelerated ZVI corrosion in the galvanic ZVI/PAC microcells and ensuing formation of DMA/ Fe 2+ complexes that are readily adsorbed by PAC.
研究领域:
环境科学
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化学工程
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水处理
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DOI
PubMed
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Jian Liu,Xueren Huang,Zhengji Yi
Complexing agents (CAs) can be used for the removal of Cr(VI) via nanoscale Fe 0 (nZVI) reduction in cost-effective manner. However, nZVI is prone to aggregation and passivation, and some conventional CAs are toxic and difficult to biodegrade, potentially causing secondary pollution. Therefore, selecting an environmentally friendly CA for assisting in the removal of Cr(VI) via supported nZVI is imperative. Herein, NaA molecular sieve membrane-supported nZVI (nZVI/NaA-NF) was prepared via the secondary growth and liquid-phase reduction method using nickel foam (NF) as the carrier. The physicochemical characteristics of nZVI/NaA-NF before and after reaction were analysed via SEM, EDS, and XPS. A CA-improved nZVI/NaA-NF was used for the effective removal of Cr(VI) in a continuous fixed-bed system. Furthermore, the influences of various experimental factors including the CA type, CA concentration, solution pH, space velocity, and inlet Cr(VI) concentration on Cr(VI) removal were systematically investigated. The results demonstrated that nZVI particles were homogeneously immobilized on the NaA molecular sieve membrane/NF for fresh nZVI/NaA-NF, and tetrasodium iminidisuccinate (IDS-4Na) inhibited the aggregation of Cr(III)/Fe(III) (hydr)oxide precipitates during the reaction. IDS-4Na demonstrated excellent promotive effect on Cr(VI) removal via nZVI/NaA-NF. The breakthrough time for Cr(VI) in the addition of IDS-4Na was considerably longer than that of nZVI/NaA-NF alone. The breakthrough concentration of Cr(VI) only reached 1.1% and 9.9% of the inlet concentration at 220 and 240 min, with an IDS-4Na concentration of 4 mM, a pH of 2.5, and a space velocity of 0.265 min −1 . The Bohart–Adams model was appropriate to predict the initial part of Cr(VI) breakthrough curves in the nZVI/NaA-NF fixed bed. The saturated concentration ( N 0 ) increased with an increase in inlet Cr(VI) concentration. The Yoon–Nelson model afforded good fitting results for all breakthrough curves of Cr(VI). The k′ value increased with an increase in space velocity, and the τ value decreased.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2024
·
IF 4.9
Xinzhuang Fu,Ya Gao,Chuanxi Peng,Haisheng Han,Wei Sun,Tong Yue
The interaction of surfactants at minerals-water interfaces in flotation system plays an important role in minerals separation. Although the increasing number of reports have been published on the sodium oleate (NaOL) adsorption at the mineral–water interface, there has been little development in describing and predicting its adsorption behaviors from a quantitative molecular insight. In this study, based the adsorption experiments, the adsorption characteristics of NaOL on the hematite/quartz-water interfaces were quantitatively depicted using the surface complexation model (SCM). There was a monodentate binding form between the function group on NaOL and the hematite and quartz surface sites during SCM fitting. The binding constants (logK) of NaOL are 10.72 (≡Fe-OL) and 8.03 (≡Si-OL), respectively. Notably, there are more positive ≡FeOH 2 + site on the hematite surface, and it has strong adsorption capacity with anionic surfactant NaOL. Moreover, the minerals surface potentials, NaOL adsorption capacity and flotation recovery in mixed ore systems were successfully predicted by the model. This study provides a credible evaluation of the adsorption characteristics of NaOL under a broad scope of pH and concentration conditions. Meanwhile, quantitative analysis of surfactants adsorption at minerals-water interfaces is beneficial for the intelligence of mineral processing technology and efficient separation of minerals.
研究领域:
矿物加工工程
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界面化学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2025
·
IF 11.3
Cuili Xing,Xinyi Yao,Kaiwei Zheng,Yang Liu,Yuankui Sun,Xiaohong Guan
Efficient removal of recalcitrant Cr(III)-organic complexes is always challenged by slow decomplexation process and the possible accumulation of highly toxic Cr(VI). Herein, a sulfidated zero-valent iron coupled ozonation strategy (S-ZVI/O 3 ) was proposed to achieve efficient decomplexation and simultaneous abatement of Cr(III)-EDTA without Cr(VI) accumulation. Results revealed that S-ZVI could catalyze O 3 to enhance removal of Cr(III)-EDTA and total organic carbon. Moreover, 88.3 % of total Cr was sequestrated by S-ZVI/O 3 and the corresponding kinetic constant was 3.1 times higher than that of ZVI/O 3 . Mechanistically, electron paramagnetic resonance and probing tests verified HO • was the dominant reactive oxidation species for decomplexation of Cr(III)-EDTA in both S-ZVI/O 3 and ZVI/O 3 . More attractively, it was found that structural Fe(II) was the major O 3 activator in S-ZVI/O 3 , whereas dissolved Fe 2+ accounted for O 3 catalyzation in ZVI/O 3 . The X-ray absorption spectroscopy analysis revealed that sulfidation treatment could enhance corrosion of ZVI with the formation of sufficient Fe(II) species. The in-situ formed Fe(II) could not only transform undesired Cr(VI) back to Cr(III) but also co-precipitate with Cr(III) to form solid Fe-Cr hydroxides. Besides Cr(III)-EDTA, S-ZVI/O 3 is also applicable to other EDTA complexed heavy metals. This work would provide a new method for the heavy metal complexes removal from water.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
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