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Chromium steel from chromite ore processing residue----A valuable construction material from a waste

Jay N. MEEGODA, Wiwat KAMOLPORNWIJIT

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 159-166 doi: 10.1007/s11783-011-0325-3

摘要： As species we humans generate excessive amounts of waste and hence for sustainability we should explore innovative ways to recover them. The primary objective of this study is to demonstrate an efficient and optimum way to recover chromium and iron from chromite ore processing residues (COPR) for the production of chrome steel and stainless steel. In Hudson County, New Jersey, there are more than two million tons of leftover COPR. Part of COPR was used as fill materials for construction sites, which spread the problem to a larger area. With high solubility along with their toxicity leached chromate from COPR is threatening the environment as well as human health. In this research, COPR was thermally treated to recover iron with chromium by applying techniques used in steel manufacturing. An extensive experimental program was performed using a Thermo-Gravimetric Analyzer (TGA) and bench scale tests to thermally treat the processed chromium contaminated soils with carbon and sand at varying temperatures and under reducing environment. The optimum chemical composition of COPR and additives to be used in the melts were evaluated based upon the thermodynamic properties of the mixture to ensure good phase separation, least amounts of iron and chromium oxides in the slag and minimum variability of final product (steel or iron with chromium). The impact of other oxides on the steel making process was evaluated to minimize the adverse impact on the process. The research demonstrated the feasibility of recovering a valuable construction material (chrome steel) from a waste (COPR).

关键词： chromite ore processing residue     chromium steel     reduction     thermal treatment     beneficial use    

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Biogenic palladium prepared by activated sludge microbes for the hexavalent chromium catalytic reduction

Luman Zhou, Chengyang Wu, Yuwei Xie, Siqing Xia

《环境科学与工程前沿（英文）》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1206-4

摘要： • Pd nanoparticles could be reduced and supported by activated sludge microbes. • The effect of biomass on Pd adsorption by microbes is greater than Pd reduction. • More biomass reduces Pd particle size, which is more dispersed on the cell surface. • When the biomass/Pd add to 6, the catalytic reduction rate of Cr(VI) reaches stable. Palladium, a kind of platinum group metal, owns catalytic capacity for a variety of hydrogenations. In this study, Pd nanoparticles (PdNPs) were generated through enzymatic recovery by microbes of activated sludge at various biomass/Pd, and further used for the Cr(VI) reduction. The results show that biomass had a strong adsorption capacity for Pd(II), which was 17.25 mg Pd/g sludge. The XRD and TEM-EDX results confirmed the existence of PdNPs associated with microbes (bio-Pd). The increase of biomass had little effect on the reduction rate of Pd(II), but it could cause decreasing particle size and shifting location of Pd(0) with the better dispersion degree on the cell surface. In the Cr(VI) reduction experiments, Cr(VI) was first adsorbed on bio-Pd with hydrogen and then reduced using active hydrogen as electron donor. Biomass improved the catalytic activity of PdNPs. When the biomass/Pd (w/w) ratio increased to six or higher, Cr(VI) reduction achieved maximum rate that 50 mg/L of Cr(VI) could be rapidly reduced in one minute.

关键词： Palladium nanoparticles     Activated sludge     Hexavalent chromium    

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Stabilization of hexavalent chromium with pretreatment and high temperature sintering in highly contaminated

Haiyan Mou, Wenchao Liu, Lili Zhao, Wenqing Chen, Tianqi Ao

《环境科学与工程前沿（英文）》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1353-7

摘要： Abstract • Separate reduction and sintering cannot be effective for Cr stabilization. • Combined treatment of reduction and sintering is effective for Cr stabilization. • Almost all the Cr in the reduced soil is residual form after sintering at 1000°C. This study explored the effectiveness and mechanisms of high temperature sintering following pre-reduction with ferric sulfate (FeSO4), sodium sulfide (Na2S), or citric acid (C6H8O7) in stabilizing hexavalent chromium (Cr(VI)) in highly contaminated soil. The soil samples had an initial total Cr leaching of 1768.83 mg/L, and Cr(VI) leaching of 1745.13 mg/L. When FeSO4 or C6H8O7 reduction was followed by sintering at 1000°C, the Cr leaching was reduced enough to meet the Safety Landfill Standards regarding general industrial solid waste. This combined treatment greatly improved the stabilization efficiency of chromium because the reduction of Cr(VI) into Cr(III) decreased the mobility of chromium and made it more easily encapsulated in minerals during sintering. SEM, XRD, TG-DSC, and speciation analysis indicated that when the sintering temperature reached 1000°C, almost all the chromium in soils that had the pre-reduction treatment was transformed into the residual form. At 1000°C, the soil melted and promoted the mineralization of Cr and the formation of new Cr-containing compounds, which significantly decreased subsequent leaching of chromium from the soil. However, without reduction treatment, chromium continued to leach from the soil even after being sintered at 1000°C, possibly because the soil did not fully fuse and because Cr(VI) does not bind with soil as easily as Cr(III).

关键词： Chromium     Heavy contaminated soil     Reduction     Sintering     Stabilization     Speciation    

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Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon

《环境科学与工程前沿（英文）》 2022年 第16卷 第5期 doi: 10.1007/s11783-021-1491-6

摘要：

• A high-efficiency N-doped porous carbon adsorbent for Cr(VI) was synthesized.

关键词： Chromium(VI)     Nitrogen-doped porous carbon     Adsorption     Reduction     Loofah sponge    

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Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

Shucai LI, Tingting LI, Gang LI, Fengmei LI, Shuhai GUO

《环境科学与工程前沿（英文）》 2012年 第6卷 第6期   页码 869-874 doi: 10.1007/s11783-012-0437-4

摘要： As a new technology used for the cleaning of chromium-contaminated soil, worldwide interest in eletrokinetic (EK) remediation has grown considerably in recent times. However, owing to the fact that chromium exists as both cationic and anionic species in the soil, it is not an efficient method. This paper reports upon a study in which a process using approaching anodes (AAs) was used to enhance the removal efficiency of chromium by eletrokinetics. Two bench-scale experiments to remove chromium from contaminated soil were performed, one using a fixed anode (FA) and the other using AAs. In the AAs experiment, the anode moved toward the cathode by 7 cm every three days. After remediation, soil pH, total chromium, and fractionation of chromium in the soil were determined. The average removal efficiency of total chromium was 11.32% and 18.96% in the FA and AAs experiments, respectively. After remediation, acidic soil conditions throughout the soil were generated through the use of AAs, while 80% of the soil remained neutral or alkalic when using the FA approach. The acidic soil environment and high field intensity in the AAs experiment might have favored chromium desorption, dissolution and dissociation from the soil, plus the mobility of chromium in the soil was also enhanced. The results demonstrate that AAs used in the process of EK remediation can enhance the efficiency of chromium removal from soil.

关键词： approaching anodes     chromium-contaminated soil     electrokinetics     chromium fractionation    

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Effects of irradiation on chromium’s behavior in ferritic/martensitic FeCr alloy

Xinfu HE, Wen YANG, Zhehao QU, Sheng FAN

《能源前沿（英文）》 2009年 第3卷 第2期   页码 181-183 doi: 10.1007/s11708-009-0025-x

摘要： The effects of irradiation on chromium performance under different temperatures in Fe-20at%Cr were modeled by modified Marlowe code. Chromium precipitation was observed in FeCr alloy after irradiation; interstitial Chromium atoms are the preferred formation of mixed Fe-Cr dumbbells in the direction of<110>and<111>; interstitial chromium atoms congregated on {111} and {110} plane. The results are compared with experiment observations and are useful to understanding the irradiation performances of FeCr alloy.

关键词： irradiation     Fe-20at%Cr alloy     chromium segregation    

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Electroreduction of hexavalent chromium using a porous titanium flow-through electrode and intelligent

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1697-x

摘要：

● Titanium-based flow-through electrode achieved high Cr(VI) reduction efficiency.

关键词： Flow-through electrode     Hexavalent chromium     Heavy metals     Neural network     Artificial intelligence    

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Hexavalent chromium in drinking water: Chemistry, challenges and future outlook on Sn(II)- and photocatalyst-based

Haizhou Liu, Xuejun Yu

《环境科学与工程前沿（英文）》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1267-4

摘要： Abstract • Wide occurrence of Cr(VI) in US source drinking water. • A strong dependence of occurrence on groundwater sources. • Elucidate Redox and equilibrium chemistry of Cr(VI). • Sn(II)-based and TiO2-based reductive treatments hold extreme promise. • Key challenges include residual waste, Cr(VI) re-generation and socioeconomic drivers. Chromium (Cr) typically exists in either trivalent and hexavalent oxidation states in drinking water, i.e., Cr(III) and Cr(VI), with Cr(VI) of particular concern in recent years due to its high toxicity and new regulatory standards. This Account presented a critical analysis of the sources and occurrence of Cr(VI) in drinking water in the United States, analyzed the equilibrium chemistry of Cr(VI) species, summarized important redox reaction relevant to the fate of Cr(VI) in drinking water, and critically reviewed emerging Cr(VI) treatment technologies. There is a wide occurrence of Cr(VI) in US source drinking water, with a strong dependence on groundwater sources, mainly due to naturally weathering of chromium-containing aquifers. Challenges regarding traditional Cr(VI) treatment include chemical cost, generation of secondary waste and inadvertent re-generation of Cr(VI) after treatment. To overcome these challenges, reductive Cr(VI) treatment technologies based on the application of stannous tin or electron-releasing titanium dioxide photocatalyst hold extreme promise in the future. To moving forward in the right direction, three key questions need further exploration for the technology implementation, including effective management of residual waste, minimizing the risks of Cr(VI) re-occurrence downstream of drinking water treatment plant, and promote the socioeconomic drivers for Cr(VI) control in the future.

关键词： Chromium     Chemistry     Treatment     Future outlook    

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Effects of reducing agent and approaching anodes on chromium removal in electrokinetic soil remediation

Xiaona WEI,Shuhai GUO,Bo WU,Fengmei LI,Gang LI

《环境科学与工程前沿（英文）》 2016年 第10卷 第2期   页码 253-261 doi: 10.1007/s11783-015-0791-0

摘要： A soil remediation method combining in situ reduction of Cr(VI) with approaching anodes electrokinetic (AAs-EK) remediation is proposed. EK experiments were conducted to compare the effect of approaching anodes (AAs) and fixed electrodes (FEs) with and without sodium bisulfite (NaHSO ) as a reducing agent. When NaHSO was added to the soil before EK treatment, 90.3% of the Cr(VI) was reduced to Cr(III). EK experiments showed that the adverse effect of contrasting migration of Cr(III) and Cr(VI) species, which limits the practical application of this technique, was eliminated in the presence of the reducing agent. Furthermore, Tessier fractionation analysis indicated that the reducing agent changed the distribution of the chemical forms of Cr. The AAs-EK method was shown to acidize the soil as the anode moved toward the cathode and this acid front pushed the “focusing” region toward the cathode. After remediation, the pH of the soil was between 1.8 and 5.0 in AAs-EK experiments. The total Cr removal efficiency was 64.4% (except in the “focusing” region) when the reduction reaction was combined with AAs-EK method. We conclude that AAs-EK remediation in the presence of NaHSO is an appropriate method for Cr-contaminated soil.

关键词： chromium     reduction reaction     contrasting migration     approaching anode     electrokinetic    

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from metagenomic, metatranscriptomic, and molecular ecological network analyses into the effects of chromium

Quan Zheng, Minglu Zhang, Tingting Zhang, Xinhui Li, Minghan Zhu, Xiaohui Wang

《环境科学与工程前沿（英文）》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1239-8

摘要： Abstract • Cr NPs significantly promoted the denitrifying process and phosphorus removal. • The quantities of denitrifying and phosphorus genes greatly increased. • The transcription of denitrifying and phosphorus genes greatly increased. • The networks associated with nitrogen and phosphorus removal became complicated. • Cr NPs decreased some genera related to GAOs. The objectives of this study were to investigate the influence of chromium nanoparticles (Cr NPs) on the nitrogen and phosphorus removal performance and the bacterial structures of an activated sludge (AS) system. Also, we through molecular ecological networks (MENs) discussed the bacterial interactions. At last we researched the change of the functional genes and their expression patterns related to nitrogen and phosphorus removal in an AS system. The results showed that long-term exposure to 1 mg/L Cr NPs significantly promoted the denitrifying process and phosphorus removal in the AS system. The relative abundance of denitrifying and phosphorus removal microorganisms, such as Denitratisoma, Thauera, Dechloromonas, and Defluviicoccus, increased significantly. Candidatus Accumulibacter, well-known as polyphosphate-accumulating organisms (PAOs), increased significantly; the relative abundance of Candidatus Competibacter, known as glycogen-accumulating organisms (GAOs), decreased significantly. Furthermore, metagenomic and metatranscriptomic analysis revealed that most of the genera related to denitrifying and phosphorus removal had greatly increased, according to the quantities of denitrifying and phosphorus genes, and the corresponding transcription likewise greatly increased. Lastly, MENs analysis showed that although the overall network became smaller and looser in the presence of Cr NPs, the microbial connections among members related to nitrogen and phosphorus removal were enhanced. The abundance increases of denitrifiers and PAOs, and their increased transcription of functional genes, together with the enhanced interactions may be associated with the promotion of the denitrifying process and phosphorus removal.

关键词： Chromium nanoparticles (Cr NPs)     Metagenomic analysis     Metatranscriptomic analysis     Molecular ecological networks (MENs)     Nitrogen and phosphorus removal    

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Reduction of hexavalent chromium with scrap iron in a fixed bed reactor

Yin WANG, Xuejiang WANG, Xin WANG, Mian LIU, Siqing XIA, Daqiang YIN, Yalei ZHANG, Jianfu ZHAO

《环境科学与工程前沿（英文）》 2012年 第6卷 第6期   页码 761-769 doi: 10.1007/s11783-012-0413-z

摘要： The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time (EBCT), and initial Cr(VI) concentration on Cr(VI) reduction were studied. The results showed that the pH, EBCT, and initial Cr(VI) concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57 mg Cr(VI)·g Fe at pH 3, 5, and 7 (initial Cr(VI) concentration 4 mg·L , EBCT 2 min, and temperature 25°C), 0.51, 1.51, and 2.85 mg Cr(VI)·g Fe at EBCTs of 0.5, 2.0, and 6.0 min (initial Cr(VI) concentration 4 mg·L , pH 5, and temperature 25°C), and 2.99, 1.51, and 1.01 mg Cr(VI)·g Fe at influent concentrations of 1, 4, and 8 mg·L (EBCT 2 min, pH 5, and temperature 25°C), respectively. Fe(total) concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr(VI) ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr ·g Fe. Scanning electron microscope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron.

关键词： hexavalent chromium     scrap iron     reduction capacity     drinking water    

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Chromium phytoextraction and physiological responses of the hyperaccumulator Swartz to plant growth-promoting

《环境科学与工程前沿（英文）》 2023年 第17卷 第1期 doi: 10.1007/s11783-023-1609-0

摘要：

● Improved Cr phytoextration efficiency was achieved by B. cereus inoculation.

关键词： Hexavalent chromium     Hyperaccumulator     Rhizobacteria     Leersia hexandra Swartz     Bacillus cereus     Consortia    

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Kinetics of hexavalent chromium reduction by iron metal

QIAN Huijing, WU Yanjun, LIU Yong, XU Xinhua

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 51-56 doi: 10.1007/s11783-008-0010-3

摘要： The kinetics of Cr(VI) reduction to Cr(III) by metallic iron (Fe) was studied in batch reactors for a range of reactant concentrations, pH and temperatures. Nearly 86.8% removal efficiency for Cr(VI) was achieved when Fe concentration was 6 g/L (using commercial iron powder (< 200 mesh) in 120 min). The reduction of hexavalent chromium took place on the surface of the iron particles following pseudo-first order kinetics. The rate of Cr(VI) reduction increased with increasing Fe addition and temperature but inversely with initial pH. The pseudo-first-order rate coefficients () were determined as 0.0024, 0.010, 0.0268 and 0.062 8 min when iron powder dosages were 2, 6, 10 and 14 g/L at 25°C and pH 5.5, respectively. According to the Arrehenius equation, the apparent activation energy of 26.5 kJ/mol and pre-exponential factor of 3 330 min were obtained at the temperature range of 288–308 K. Different Fe types were compared in this study. The reactivity was in the order starch-stabilized Fe nanoparticles > Fe nano-particles > Fe powder > Fe filings. Electrochemical analysis of the reaction process showed that Cr(III) and Fe(III) hydroxides should be the dominant final products.

关键词： Different     process     surface     Electrochemical analysis     concentration    

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The biosorption of Cr(VI) ions by dried biomass obtained from a chromium-resistant bacterium

Paul Fabrice NGUEMA,Zejiao LUO,Jingjing LIAN

《化学科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 454-464 doi: 10.1007/s11705-014-1456-4

摘要： The biosorption potential of many different kinds of biomaterials has been widely studied. However, there is little data on the biosorption mechanism of Cr(VI) by dried biomass. So the bio-removal of Cr(VI) ions from aqueous solutions was investigated using dried biomass from a chromium-resistant bacterium. The bacterium was isolated from dewatered sludge samples that were obtained from a sewage treatment plant. Equilibrium and kinetic experiments were performed at different metal concentrations, pH values, and biosorbents dosages. The biomass was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The functional groups in the biomass which may play a role in the biosorption process were identified by Fourier transform infrared spectroscopy. The biosorption process was found to be highly pH dependent and the optimum pH for the adsorption of Cr(VI) was 2.0±0.3 at 30±2 °C. The experimental data fit well with Langmuir and Freundlich models as well as a pseudo-second order kinetic model. The mechanism for the biosorption was also studied by fitting the kinetic data with an intra-particle diffusion model and a Boyd plot. External mass transfer was found to be the rate-determining step for the adsorption process. Biosorption could be an alternative mechanism besides bio-oxidation and bio-reduction for the bioremediation of heavy metals.

关键词： Cr(VI)     biomass     Bacillus cereus Pf-1     biosorption capacity     biosorbents    

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含铬废水常温合成铬铁矿的结晶行为及稳定性 Article

吕晋芳, 全英聪, 童雄, 彭勇军, 郑永兴

《工程（英文）》 2022年 第9卷 第2期   页码 67-76 doi: 10.1016/j.eng.2020.12.018

摘要：

铁氧体法不仅能净化含重金属废水，而且能从废水中回收有价金属。因此，铁氧体法被认为是一种处理含铬废水最具潜力的技术。然而，由于高的合成温度，该技术尚未在工业上得到广泛应用。本文对常温合成铬铁矿的可行性进行全面研究。考查了关键因素对出水水质、合成产物结晶行为和稳定性的影响。结果表明，经过常温铁氧体法处理后，废水中铬的去除率超过99.0%，上清液中铬的浓度达到污水排放标准。提高充气速率、搅拌速率和反应时间有利于稳定铬铁矿的形成。通过常温铁氧体法获得的颗粒结构致密，最大粒径可达52 μm。在合成过程中，铬逐渐地进入尖晶石晶体结构，合成铬铁矿的分子式为Fe3-xCrxO4，其中x约0.30。为阐明常温环境下铬铁矿的合成机理，提出了微观反应路径。本研究为铁氧体法在含铬废水净化和综合利用方面的工业应用奠定了基础。

关键词： 含铬废水     铬铁矿合成     常温     结晶行为     稳定性    

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标题 作者 时间 类型 操作

Chromium steel from chromite ore processing residue----A valuable construction material from a waste

Jay N. MEEGODA, Wiwat KAMOLPORNWIJIT

期刊论文

Biogenic palladium prepared by activated sludge microbes for the hexavalent chromium catalytic reduction

Luman Zhou, Chengyang Wu, Yuwei Xie, Siqing Xia

期刊论文

Stabilization of hexavalent chromium with pretreatment and high temperature sintering in highly contaminated

Haiyan Mou, Wenchao Liu, Lili Zhao, Wenqing Chen, Tianqi Ao

期刊论文

Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon

期刊论文

Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

Shucai LI, Tingting LI, Gang LI, Fengmei LI, Shuhai GUO

期刊论文

Effects of irradiation on chromium’s behavior in ferritic/martensitic FeCr alloy

Xinfu HE, Wen YANG, Zhehao QU, Sheng FAN

期刊论文

Electroreduction of hexavalent chromium using a porous titanium flow-through electrode and intelligent

期刊论文

Hexavalent chromium in drinking water: Chemistry, challenges and future outlook on Sn(II)- and photocatalyst-based

Haizhou Liu, Xuejun Yu

期刊论文

Effects of reducing agent and approaching anodes on chromium removal in electrokinetic soil remediation

Xiaona WEI,Shuhai GUO,Bo WU,Fengmei LI,Gang LI

期刊论文

from metagenomic, metatranscriptomic, and molecular ecological network analyses into the effects of chromium

Quan Zheng, Minglu Zhang, Tingting Zhang, Xinhui Li, Minghan Zhu, Xiaohui Wang

期刊论文

Reduction of hexavalent chromium with scrap iron in a fixed bed reactor

Yin WANG, Xuejiang WANG, Xin WANG, Mian LIU, Siqing XIA, Daqiang YIN, Yalei ZHANG, Jianfu ZHAO

期刊论文

Chromium phytoextraction and physiological responses of the hyperaccumulator Swartz to plant growth-promoting

期刊论文

Kinetics of hexavalent chromium reduction by iron metal

QIAN Huijing, WU Yanjun, LIU Yong, XU Xinhua

期刊论文

The biosorption of Cr(VI) ions by dried biomass obtained from a chromium-resistant bacterium

Paul Fabrice NGUEMA,Zejiao LUO,Jingjing LIAN

期刊论文

含铬废水常温合成铬铁矿的结晶行为及稳定性

吕晋芳, 全英聪, 童雄, 彭勇军, 郑永兴

期刊论文