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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    

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    

Hyperbranched magnetic polymer: highly efficient removal of Cr(VI) and application in electroplating

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1568-1580 doi: 10.1007/s11705-023-2303-2

摘要: By using a two-step hydrothermal method and trithiocyanuric acid (TTCA), 2,4,6-trihydrazino-1,3,5-triazine (THT), and Fe3O4 as raw materials, a spherical magnetic adsorbent polymer (TTCA/THT@Fe3O4) was synthesized to achieve the efficient removal of Cr(VI) from wastewater. Under optimal adsorption conditions, the maximum adsorption capacity of TTCA/THT@Fe3O4 for Cr(VI) can reach 1340 mg∙g‒1. Notably, the removal efficiency can approach 98.9%, even at the lower concentration of 20 mg∙L‒1 Cr(VI). For actual wastewater containing Cr(VI), the Cr(VI) concentration was reduced from 25.8 to 0.4 mg∙L‒1, a remarkable 20% lower than the current industry discharge standard value. A mechanism for the high adsorption performance of Cr(VI) on TTCA/THT@Fe3O4 was investigated using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and density functional theory. It can be plausibly attributed to the formation of Cr/N and Cr/S coordination bonds. Additionally, surface electrostatic adsorption, reduction effects, and the spherical polymer structure increase the contact area with Cr(VI), maximizing adsorption. The synergistic effect of adsorption and reduction enhances the adsorption performance of TTCA/THT@Fe3O4 for Cr(VI) and total chromium in water. The resultant polymer has a simple preparation process, excellent adsorption performance, easy magnetic separation, and promising application for actual wastewater.

关键词: magnetic polymer     chromium removal     hydrogen bonding     recyclability     actual wastewater    

Effects of phosphorus concentration on Cr(VI) sorption onto phosphorus-rich sludge biochar

DING Wenchuan,PENG Wenlong,ZENG Xiaolan,TIAN Xiumei

《环境科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 379-385 doi: 10.1007/s11783-013-0606-0

摘要: To investigate effects of phosphorus content on Cr(VI) sorption onto phosphorus-rich biochar, sewage sludge of different phosphorus concentrations from 4 to 60 mg·g by dry weight were prepared and carbonized to make biochar for batch sorption experiments. Test results revealed that different phosphorous concentration of raw sludge had respective impacts on surface area, pore surface area, average pore diameter and pH value of derived biochar. The adsorption kinetics of phosphorus-rich biochar could be described by the pseudo-second-order model. The sorption isotherm data followed Langmiur model better than Freundlich model. Biochar produced from sludge with phosphorus concentration of 20 mg·g gave the largest chromium sorption capacity, which could be attributed to its largest surface area and pores surface area comparing with those of biochars from sludge with other phosphorus concentrations. The chromium loaded biochar was analyzed using Fourier Transform Infrared Spectroscopy and X-ray Diffraction measurement. The results indicated that chemical functional groups hydroxyl and methyl on surface of biochar were involved in Cr(VI) binding and its reducing to Cr(III). Then, a portion of Cr(III) in form of various phosphate precipitates was bound onto biochar surface and the rest was released into the solution. The experimental results suggested that phosphorus played an important role in pore and surface area development of sludge biochar during pyrolytic process. It also could react with Cr(III) on the biochar surface that impacted on capacity of Cr(VI) removal from solution by sludge biochar. Therefore, phosphorus concentration in sludge should be considered when sludge pyrolytic residue would be reused for heavy metals sorbing.

关键词: phosphorus     biochar     sewage sludge     hexavalent chromium     adsorption    

Na-P1 from coal fly ash produced by gasification and its application as adsorbent for removal of Cr(VI

Yixin Zhang, Lu Zhou, Liqing Chen, Yang Guo, Fanhui Guo, Jianjun Wu, Baiqian Dai

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 518-527 doi: 10.1007/s11705-020-1926-9

摘要: The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021. It has mainly been disposed as solid waste by landfill. There is lack of study focused on its utilization. In this paper, the coal fly ash produced by gasification was at first analyzed and then applied to synthesize zeolite as an adsorbent. The effects of synthesis conditions on the cation exchange capacity (CEC) of zeolite were investigated. The results from X-ray diffraction and scanning electron microscope indicated that the crystallinity of the synthesized zeolite is the most important factor to affect the CEC. When the synthesized zeolite with the highest CEC (275.5 meq/100 g) was used for the adsorption of Cr(VI) from aqueous solution, the maximum adsorption capacity for Cr(VI) was found to be 17.924 mg/g. The effects of pH, contact time and initial concentration on the adsorption of Cr(VI) were also investigated. The adsorption kinetics and isotherms can be well described by the pseudo-second-order model and Langmuir isotherm model, respectively.

关键词: coal fly ash     gasification     zeolite     Na-P1     chromium(VI)    

Dual-functional sites for synergistic adsorption of Cr(VI) and Sb(V) by polyaniline-TiO hydrate: Adsorption

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1526-7

摘要:

• PANI/Ti(OH)n(4n)+ exhibited excellent adsorption capacity and reusability.

关键词: Polyaniline/TiO2     Chromium     Antimony     Adsorption     Desorption     Mechanism    

In situ synthesis of FeS/Carbon fibers for the effective removal of Cr(VI) in aqueous solution

Rongrong Zhang, Daohao Li, Jin Sun, Yuqian Cui, Yuanyuan Sun

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1247-8

摘要: Abstract • FeS/carbon fibers were in situ synthesized with Fe-carrageenan hydrogel fiber. • The double helix structure of carrageenan is used to load and disperse Fe. • Pyrolyzing sulfate groups enriched carrageenan-Fe could easily generate FeS. • The adsorption mechanisms include reduction and complexation reaction. Iron sulfide (FeS) nanoparticles (termed FSNs) have attracted much attention for the removal of pollutants due to their high efficiency and low cost, and because they are environmentally friendly. However, issues of agglomeration, transformation, and the loss of active components limit their application. Therefore, this study investigates in situ synthesized FeS/carbon fibers with an Fe-carrageenan biomass as a precursor and nontoxic sulfur source to ascertain the removal efficiency of the fibers. The enrichment of sulfate groups as well as the double-helix structure in ι-carrageenan-Fe could effectively avoid the aggregation and loss of FSNs in practical applications. The obtained FeS/carbon fibers were used to control a Cr(VI) polluted solution, and exhibited a relatively high removal capacity (81.62 mg/g). The main mechanisms included the reduction of FeS, electrostatic adsorption of carbon fibers, and Cr(III)-Fe(III) complexation reaction. The pseudo-second-order kinetic model and Langmuir adsorption model both provided a good fit of the reaction process; hence, the removal process was mainly controlled by chemical adsorption, specifically monolayer adsorption on a uniform surface. Furthermore, co-existing anions, column, and regeneration experiments indicated that the FeS/carbon fibers are a promising remediation material for practical application.

关键词: Carrageenan     FeS     Double-helix structure     Hexavalent chromium    

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    

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    

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    

Magnetic KIT-6 nano-composite and its amino derivatives as convenient adsorbent for U(VI) sequestration

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2037-2049 doi: 10.1007/s11705-023-2358-0

摘要: Although mesoporous silica with magnetically hybridized two-dimensional channel structures has been well studied in recent years, it remains a challenge to fabricate the counterpart with macroporous three-dimensional cubic structures since the highly acidic preparation conditions lead to dissolution of magnetic particles. Herein, we successfully prepared magnetic KIT-6 nano-composite and its amino derivatives by bearing acid-resistant iron oxide. The prepared materials exhibited excellent properties for U(VI) ions removal from aqueous solutions under various conditions. The experimental data show that the U(VI) adsorption features fast adsorption kinetics, high adsorption capacity and ideal selectivity toward U(VI). The adsorption process is of spontaneous and endothermic nature and ionic strength independence, and the adsorbents can be easily regenerated by acid treatment. Compared to pristine KIT-6, the introduction of magnetism does not reduce the efficiency of the material to remove U(VI) while exerting its role as a recovery adsorbent. The findings of this work further demonstrate the potential broad application prospects of magnetic hybrid mesoporous silica in radionuclide chelation.

关键词: magnetic nanoparticle     3D mesoporous silica     amino functionalization     adsorption of U(VI)     acid resistance    

Decontamination of Cr(VI) facilitated formation of persistent free radicals on rice husk derived biochar

Kaikai Zhang, Peng Sun, Yanrong Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1106-7

摘要:

PFRs were produced on biochar during Cr(VI) decontamination.

PFRs formation on biochar was owing to the oxidization of phenolic-OH by Cr(VI).

Appearance of excessive oxidant led to the consumption of PFRs on biochar.

Biochar charred at high temperature possessed great performance to Cr(VI) removal.

关键词: Biochar     Persistent free radicals     Phenolic hydroxyl groups     Cr(VI) reduction    

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    

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    

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    

标题 作者 时间 类型 操作

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

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

Hyperbranched magnetic polymer: highly efficient removal of Cr(VI) and application in electroplating

期刊论文

Effects of phosphorus concentration on Cr(VI) sorption onto phosphorus-rich sludge biochar

DING Wenchuan,PENG Wenlong,ZENG Xiaolan,TIAN Xiumei

期刊论文

Na-P1 from coal fly ash produced by gasification and its application as adsorbent for removal of Cr(VI

Yixin Zhang, Lu Zhou, Liqing Chen, Yang Guo, Fanhui Guo, Jianjun Wu, Baiqian Dai

期刊论文

Dual-functional sites for synergistic adsorption of Cr(VI) and Sb(V) by polyaniline-TiO hydrate: Adsorption

期刊论文

In situ synthesis of FeS/Carbon fibers for the effective removal of Cr(VI) in aqueous solution

Rongrong Zhang, Daohao Li, Jin Sun, Yuqian Cui, Yuanyuan Sun

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

Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

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

期刊论文

Magnetic KIT-6 nano-composite and its amino derivatives as convenient adsorbent for U(VI) sequestration

期刊论文

Decontamination of Cr(VI) facilitated formation of persistent free radicals on rice husk derived biochar

Kaikai Zhang, Peng Sun, Yanrong Zhang

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