WATER AIR AND SOIL POLLUTION
·
2016
·Vol. 228
·期 1
·1-12
·
IF 1.551
Jiang Meng,Qi Yun,Cui Yuan-Lu,Zhao Lin,Liu Shejiang
A rutin-Cr(III) loaded alginate microspheres, which can act as reduction-adsorption microreactor, was designed to reduce Cr(VI) to Cr(III) and recover it. Different from the rutin-Cr(III) complex in alginate-chitosan microcapsule we previously reported, which can sustained release rutin-Cr(III) and reduce Cr(VI) to Cr(III), this microreactor can not only reduce Cr(VI) but also adsorb/recover Cr(III) in aqueous solution. This microreactor was prepared by loading metal complex of rutin into alginate microsphere. It was found that Cr(VI) was initially reduced to Cr(III) by rutin-Cr(III), and then the product Cr(III) was absorbed in the microspheres. Both Cr(VI) reduction rate and Cr(III) adsorption rate were pH-dependent. Cr(VI) can be completely reduced to Cr(III) at pH 1–4 with a reduction capability of 1.27 (±0.078) mmol/g (pH 1, 4 h). The highest blank alginate microsphere adsorption capacity was 1.82 (±0.042) mmol/g at pH 4. It was assumed that reduction-adsorption was the mechanism of total Cr removal by the reduction-absorption microreactor. Recovery experiment showed that 93% and 98% of Cr(III) can be recovered by EDTA and sodium citrate, respectively.
研究领域:
环境科学
·
生物化学
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产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2019
·
IF 3.019
Dayan Xie,Kuibao Zhang,Weiwei Li,Baozhu Luo,Haibin Zhang
Lanthanum chromite (LaCrO 3 ) is a promising functional material because of its high melting point, high thermal conductivity and excellent fire resistance. In this study, LaCrO 3 was successfully prepared by self-propagating high-temperature synthesis (SHS) method using CrO 3 and Cr as the oxidant and reductant. The optimum mole ratio of La 2 O 3 , Cr and CrO 3 was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result shows that the LaCrO 3 powder with acceptable purity and good morphology was obtained when Cr and CrO 3 are 10% excess over La 2 O 3 . The real temperature of SHS system reaction was recorded by paperless recorder. The particle size distribution of the SHS prepared LaCrO 3 powder demonstrates median diameter of 1040 nm according to laser particle size spectrometer.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2020
·
IF 4.872
Teng Xu,Feng Nan,Xiaofeng Jiang,Yuling Tang,Yunhang Zeng,Wenhua Zhang,Bi Shi
This work was conducted to study the effect of soil pH (4.0, 6.0, and 8.0) on the transport, fractionation, and oxidation of trivalent chromium [Cr(III)]. Variation in pH altered soil chemical and mineralogical properties such as zeta potential, cation exchange capacity and redox potential of natural soil. Breakthrough curves and batch sorption experiments coupled with fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses demonstrated that the easy mobility of Cr(III) in pH 4.0 soil was dominated by the limited coordination effect. The high retention of Cr(III) in pH 8.0 soil was mainly ascribed to the hydrolysis. Incubation experiments indicated that the proportions of Cr in exchangeable fraction decreased with increasing of soil pH and incubation time, and kinetics analysis revealed that the time dependent transformation was controlled by mass transfer and chemical processes (e.g., hydrolysis, ion association). The XPS confirmed the oxidation of Cr(III) in pH 8.0 soil during the incubation period. Furthermore, the content of toxic hexavalent chromium [Cr(VI)] was positively associated with time and initial concentration of Cr(III) released. These results revealed the hazardousness of Cr(III) in soil contaminated simultaneously by inorganic acid and alkali.
研究领域:
环境科学
·
土壤化学
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DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Jing Yang,Ruixue Wang,Ziyi Cheng,Yucheng Chen,Lei Li,Xingrun Wang
Current technologies for removal of Cr(VI) are generally fit for acidic wastewater. In this study, a new ferrite process for removal and recycling of Cr(VI) from alkaline wastewater to produce the valuable chromium ferrite has been developed. The results show that this new ferrite method is a one-step process which can be divided into two successive reactions including Cr(VI) reduction to form coprecipitation (Cr 0.25 Fe 0.75 (OH) 3 ) and subsequently magnetic conversion of Cr 0.25 Fe 0.75 (OH) 3 induced by Fe 2+ under the same alkaline condition. The total Fe/Cr mole ratio of 5:1 is at least required for the chromium ferrite transformation. Increasing temperature and pH can enhance the interaction of Fe 2+ with Cr 0.25 Fe 0.75 (OH) 3 and further promote the formation of chromium ferrite, while suppressing the generation of nonmagnetic by-product goethite. Almost pure chromium ferrite is formed under proposed optimum conditions (Fe/Cr = 7:1, 65 °C and pH of 9) with Cr(VI) removal ratio around 100%. The Cr(VI) remained in the filtrate can be reduced to 0.01 mg/L which is much lower than the limits concentration for surface water (≤0.05 mg/L). The chromium ferrite product whose molecular formula can be expressed as Cr 0.5-x Fe 2.5+x O 4 (where 0 ≤ x < 0.5) presents good magnetic properties and has the potential to be recycled as a useful material.
研究领域:
环境科学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
GEOMICROBIOLOGY JOURNAL
·
2015
·
IF 1.44
Hongliang Liu,Jun Huang,Shengzhe Zhang,Biao Xu,Gejiao Wang
This study was conducted to determine the microbe-chromate [Cr(VI)] interaction and the effect of quinoid analogue anthraquinone-2-sulfonate (AQS) on aerobic Cr(VI) reduction by Intrasporangium chromatireducens Q5-1. The addition of redox mediator AQS, which might expedite the electron transfer, promoted Cr(VI) bioreduction. Addition of carbon sources, such as maltose, acetate, sucrose and lactose stimulated the AQS-promoted Cr(VI) reduction of strain Q5-1. Induction experiment clarified that the enzyme involves in the Cr(VI) reduction is constitutive. Energy-dispersive spectroscopy (EDS) spectra showed the existence of trace Cr distributed on the cell surface. X-ray photoelectron spectroscopy (XPS) analysis revealed that the Cr(III) complex was bound to the cell surface (0.87%, atomic percent). The spectra shifts detected by Fourier transform infrared (FTIR) spectroscopy indicated that Cr(III) was bound to the carbonyl and amide groups. In addition, Cr(VI) reduction by different cell fractions showed that Cr(VI) reduction was occurred extracellularly rather than intracellularly. The results disclosed that Cr(VI) detoxification of strain Q5-1 was mainly associated with extracellular Cr(VI) reduction process in combination with trace Cr(III) adsorption on the cell surface. A schematic figure depicting the interactions between strain Q5-1 and Cr(VI) was presented. This study enhanced the understanding of the microbe-Cr(VI) interaction mechanism and revealed the AQS-promoted aerobic Cr(VI) reduction of strain Q5-1. Such strain and quinoid analogue-mediated bacterial Cr(VI) reduction may facilitate the bioremediation for Cr(VI)-polluted environment.
研究领域:
微生物学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Yun Guo,Hong-Yi Li,Shuo Shen,Jie Cheng,Jiang Diao,Bing Xie
Chromium sludge is a hazardous solid waste which cannot be effectively treated but only piled up and abandoned, causing serious environment pollution and resource wasting. This work proposes an effective novel process to separately recover all resources in chromium sludge via a sustainable way. The obtained acid solving liquid from chromium sludge is desiliconized by cationic flocculant (PCAM) to induce coprecipitation of polysilicate gel and PCAM , which mixture is calcinated to generate the product of white carbon black in purity of 94.35% with a recovery of 92.58%. After desiliconization, V in the solving liquid is selectively extracted by microemulsion (ME), which is recovered as V 2 O 5 in purity of 99.34% with a recovery of 95.53% by the subsequent procedure of stripping-precipitation-calcination. The Fe 3+ in raffinate is reduced to Fe 2+ cations by Na 2 SO 3 , and is then recovered by H 2 C 2 O 4 precipitation to generate the FeC 2 O 4 product in purity of 99.12% with a recovery of 98.25%. Cr 3+ cations in residual solution are recovered by alkaline precipitation and calcination to generate the Cr 2 O 3 product in purity of 98.25% with a recovery of 92.68%. This work provides fresh penetrations into the synchronous detoxification, resource recovery and value-added utilization of hazardous industrial solid wastes.
研究领域:
环境科学
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材料科学
·
化学工程
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Jing Zhang,Wenyu Xie,Shasha Chu,Zhangbin Liu,Zhen Wu,Yingying Lan,Vladimir V. Galvita,Lijuan Zhang,Xintai Su
Chromium ore processing residue (COPR) is a hazardous waste generated during the production of chromate. Currently, approximately 10% of Cr 2 O 3 cannot be extracted after chromite sodium roasting and remains in COPR, wasting valuable Cr resources. In this study, Mg was selectively removed by using (NH 4 ) 2 SO 4 roasting in combination with H 2 SO 4 leaching. The results showed that the selective removal of 79.55% Mg from COPR could be achieved under the optimum (NH 4 ) 2 SO 4 roasting conditions (80 mmol (NH 4 ) 2 SO 4 , 800 °C, 2 h). During the subsequent sodium roasting and acid leaching stages, the Cr extraction rate was 84.63% for the COPR direct roasting and 95.39% for the Mg removal residue roasting. The increased Cr extraction efficiency is attributed to the transformation of Mg-rich spinel and diopside (the Mg & Cr coexisting phases) in COPR converted into easily extractable (Fe,Cr) 2 O 3 and Cr 2 O 3 after the Mg treatment. This study investigated that the phase transformation of the Cr host phases is crucial for the sufficient extraction of Cr and provides inspiration for the development of efficient and practical Cr extraction techniques. Moreover, the method can be extended to the effective extraction of Cr from other Cr-containing wastes.
研究领域:
冶金工程
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2021
·
IF 4.837
Bin Li,Caizhu Chen,Yuwei Zhang,Le Yuan,Hong Deng,Wenmin Qian
In order to solve the problem of chrome slag returning to yellow and Red Mud accumulating in large amounts, this study proposes to use Red Mud and chromite ore process residue instead of clay to make glass-ceramics, and seal chromium, so as to achieve the purpose of waste control by waste and high-valued of final product. The Red Mud (RM), Chromite ore process residue (COPR) and silicon dioxide were homogenized in ethanol and fired at 1200 ℃ for 2 h. The results of XRD and SEM-EDS show that part of chromium enters the lattice, and the rest is wrapped in silicate glass . The leaching toxicity test data of solidified samples showed that the leaching concentrations of hexavalent chromium and total chromium were below the detection limit. In the process of sintering, solidification and preparation of glass-ceramics, Red Mud is not only used as one of the raw materials of glass-ceramics, but also plays the role of fluxing agent and nucleating agent, which greatly reduces comprehensive energy consumption and the production cost of glass-ceramics. This study provides a new way to solve the environmental problems caused by RM and COPR.
研究领域:
材料科学
·
环境科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Teng Xu,Xiaofeng Jiang,Yuling Tang,Yunhang Zeng,Wenhua Zhang,Bi Shi
The kinetics and mechanisms of the oxidation of Cr(III) in soil contaminated by unsaturated oils were investigated. Batch experiments were performed with unsaturated oils, namely, fish oil, hydrogenated lard oil, rapeseed oil, and caster oil. Impacts of environmental parameters, including temperature, soil pH, UV irradiation, oil content, and soil moisture content were examined. Results showed that oxidation of Cr(III) in oil-treated soils was accompanied by the formation of Cr(VI), which first increased and then decreased. Changes in the peroxide values of oils and the production of hexanal in the soil indicated that hydroperoxide was closely related to the formation of Cr(VI). tert -Butylhydroperoxide, as a model molecule of hydroperoxide, significantly enhanced the oxidation of Cr(III) in water. This result further showed that hydroperoxides were responsible for the oxidation of Cr(III). Native soil substances, such as organic matter, Fe(II), and microbes, and the decomposition products of hydroperoxides, such as aldehydes, could reduce Cr(VI). The change in Cr(VI) content in the soil resulted from the competition between the oxidation of Cr(III) and the reduction of Cr(VI). High temperature, high soil pH, UV irradiation, and low soil moisture content could facilitate the oxidation of Cr(III), which is of environmental significance.
研究领域:
环境科学
·
化学
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产品关联
DOI
PubMed
高影响因子
CURRENT MICROBIOLOGY
·
2013
·Vol. 68
·期 4
·448-456
·
IF 1.52
Huang Zhiwei,Kuang Xin,Chen Zhongxiang,Fang Zhijia,Wang Song,Shi Ping
Chromium is a significant mutagen and carcinogen in environment. We compared the effects of tri- and hexavalent chromium on cytotoxicity and oxidative stress in yeast . Cell growth was inhibited by Cr 3+ or Cr 6+ , and Cr 6+ significantly increased the lethal rate compared with Cr 3+ . Both Cr 3+ and Cr 6+ can enter into the yeast cells. The percent of propidium iodide permeable cells treated with Cr 3+ is almost five times as that treated with the same concentration of Cr 6+ . Levels of TBARS, O 2
− , and carbonyl protein were significantly increased in both Cr 6+ - and Cr 3+ -treated cells in a concentration- and time-dependent manner. Moreover, the accumulation of these stress markers in Cr 6+ -treated cells was over the Cr 3+ -treated ones. The decreased GSH level and increased activity of GPx were observed after 300 μM Cr 6+ -exposure compared with the untreated control, whereas there was no other change of GSH content in cells treated with Cr 3+ even at very high concentration. Exposure to both Cr 3+ and Cr 6+ resulted in the decrease of activities of SOD and catalase. Furthermore, the effect of Cr 6+ is stronger than that of Cr 3+ . Null mutation sensitivity assay demonstrated that the gsh1 mutant was sensitive to Cr 6+ other than Cr 3+ , the apn1 mutant is more sensitive to Cr 6+ than Cr 3+ , and the rad1 mutant is sensitive to both Cr 6+ and Cr 3+ . Therefore, Cr 3+ can be concluded to inhibit cell growth probably due to the damage of plasma membrane integrality in yeast. Although both tri- and hexavalent chromium can induce cytotoxicity and oxidative stress, the action mode of Cr 3+ is different from that of Cr 6+ , and serious membrane damage caused by Cr 3+ is not the direct consequence of the increase of lipid peroxidation.
研究领域:
环境科学
·
微生物学
·
毒理学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2022
·
IF 11.357
Dashi Lei,Chunli Gou,Chunli Wang,Juanqin Xue,Zhongshen Zhang,Weizhen Liu,Zhang Lin,Jing Zhang
The reduced chromite ore processing residue (rCOPR) deposited in environments is susceptible to surrounding factors and causes reoccurrence of Cr(VI). However, the impact of natural sunlight on the stability of rCOPR is still unexplored. Herein, we investigated the dissolution and transformation behaviors of Cr(III)–Fe(III) hydroxide, a typical Cr(III)-containing component in rCOPR, under visible light. At acidic conditions, the release rate of Cr(III) under illumination markedly increased, up to 7 times higher than that in the dark, yet no Cr(VI) was produced. While at basic conditions, only Cr(VI) was obtained by photo-oxidation, with an oxidation rate of ∼7 times higher than that by δ-MnO2 under dark conditions at pH 10, but no reactive oxygen species was generated. X-ray absorption near-edge structure and density functional theory analyses reveal that coexisting Fe in the solid plays a critical role in the pH-dependent release and transformation of Cr(III), where photogenerated Fe(II) accelerates Cr(III) produced at acidic conditions. Meanwhile, at basic conditions, the production of intermediate Cr(III)–Fe(III) clusters by light leads to the oxidation of Cr(III) into Cr(VI) through the nonradical “metal-to-metal charge transfer” mechanism. Our study provides a new insight into Cr(VI) reoccurrence in rCOPR and helps in predicting its environmental risk in nature.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2017
·Vol. 9
·期 30
·4471-4475
·
IF 1.9
L. F. Tian,D. S. Zou,Y. C. Dai,L. L. Wang,W. Gao
Quantification of chromium in V–Cr–Ti ternary alloys, used as candidate structural materials for fusion reactors, is essential in view of its significant effect on the properties of these vanadium-based alloys. Various methods have already been used for the determination of chromium in common alloys, but most of these methods are based on complicated and expensive instruments or suffer from the serious matrix interference of vanadium. In this study, a simple, rapid and accurate spectrophotometric method was developed for the determination of chromium in V–Cr–Ti alloys without any prior separation and chromogenic agent. The alloy samples were dissolved in diluted sulphuric acid and concentrated nitric acid, and chromium was oxidized with persulphate in the presence of Ag(I) ions as a catalyst. After alkalization of the solution with sodium hydrate, greenish-yellow coloured chromate (CrO42−) ions were formed in the alkaline solution and had a maximum absorption peak at 374 nm. Beer's law was obeyed in the range of 0.15–12.0 μg mL−1 Cr(VI) at 374 nm and the molar absorptivity was 4.8 × 103 L mol−1 cm−1. All the variables were studied in order to optimize the analytical conditions. Vanadium and titanium seriously interfered with the determination of Cr(VI) and their interference can be eliminated by addition of ammonium tartrate. The proposed method is simple, fast, accurate and of low cost, and has been satisfactorily used for the determination of chromium in V–Cr–Ti alloys. The results are in good agreement with data given by inductively coupled plasma optical emission spectrometry (ICP-OES) and the relative standard deviation is found to be lower than 0.4%.
研究领域:
分析化学
·
材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）