ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 27
·28361-28371
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IF 2.914
Yi Yunqiang,Wei Yufen,Tsang Pokeung Eric,Fang Zhanqiang
Aging effects play a crucial role in determining applications of green-synthesised iron-based nanoparticles in wastewater treatment from laboratory scale to practical applications. In this study, iron-based nanoparticles (Ec-Fe-NPs) were synthesised using the extract of Eichhornia crassipes and ferric chloride. Scanning electron microscopy (SEM) revealed that the fresh Ec-Fe-NPs were spherical and had a narrow particle size range (50 to 80 nm). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) demonstrated that the Ec-Fe-NPs were mainly amorphous in nature and consisted of Fe 0 , FeO, Fe 2 O 3 and Fe 3 O 4 . As they aged, the particle size of the liquid Ec-Fe-NPs gradually increased and then tended to stabilise. Ec-Fe-NPs that were aged for 28 days were only 19% less efficient than fresh material at removing Cr(VI). Extracts aged up to 28 days were also tested, and their antioxidant capacity was found to be 15.4% lower than that of the fresh extracts. Furthermore, the removal efficiency of Cr(VI) using iron-based nanoparticles synthesised with the aged extracts was 67.2%. Finally, the active components of the extracts, which were responsible for the reactivity and stability of the iron-based nanoparticles, were identified by liquid chromatography–mass spectrometry. Overall, green-synthesised iron-based nanoparticles show promise for Cr(VI) removal from wastewater in practical applications.
研究领域:
环境科学
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材料科学
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植物学
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DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2024
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IF 5.4
Hao Shi,Haozhen Li,Xing Zhou,Chongqing Yang,Hengyong Tu,Jun Tong,Longkai Xiang,Chao Ma,Lei Zhu,Zhen Huang
Spinels have been widely employed as contact layers (CLs) on metallic interconnects for solid oxide cells (SOCs) with the required electrical conductivity and Cr block ability. In this work, MnCo2O4 spinels doped with different transition metals (Cu, Ni, and Zn) were deposited on precoated SUS441 stainless steel as CLs. A positive doping effect of Cu and Ni on increasing the concentration of Mn4+/Mn3+ and Co3+/Co2+ hopping pairs was observed, whereas a negative doping effect of Zn on electrical conductivity was confirmed, which was reflected in the data of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectra (XAS). The Cu-doped Mn1Co1.7Cu0.3O4 spinel exhibited the best electrical conductivity with a low area specific resistance (ASR) value of 4.5 mΩ·cm2 at 850 °C. A relative degradation test demonstrated that Mn1Co1.7Cu0.3O4 maintained significant performance during a 200 h isothermal process. Cross-sectional observations revealed that the thickness of the Cr oxide scale formed during the degradation test was much reduced by the Mn1Co1.7Cu0.3O4 CL, which was attributed to the improved resistance to Cr oxidation. The present work shed light on the design of highly conductive CLs in SOCs.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Zhihao Xu,Cheng Chen,Qizhen Wu,Rui Yang,Chenguang Gao,Mingxue Liu,Ruzhen Xie,Wenyuan Hu,Ying Xiong,Faqin Dong
The α-FeOOH (021) crystal facet has a high density of active sites, and as a reactive facet, it has good adsorption of pollutants and good photocatalytic performance. In this paper, nano α-FeOOH with different (021)/(110) crystal facet ratios was prepared using crystal facet inducers (ethanol, ethylene glycol, and glycerol) via a hydrothermal method, with a (021)/(110) crystal facet ratio reaching 16% in the FG-2 sample. The results of photocatalytic experiments show that this sample’s removal rate of Cr(VI) reaches 60.70% in 4 h, which is 61.00% higher than for FC with unregulated crystal facets, and the apparent normalized photocatalytic reaction rate constant is 8.28 times higher than for FC. Kelvin probe force microscope characterization (KPFM) results and density functional theory (DFT) calculation show that FG-2’s higher rate of removal of Cr(VI) was due in large part to the different electric potentials of the (021) and (110) crystal facets. When the ratio of (021)/(110) crystal facets was changed, different electric fields resulted. Meanwhile, the high site density of the (021) crystal facet created high coordination efficiency and in addition higher reactivity resulted from the chromium ion’s lower adsorption energy that the coupling effect produced.
研究领域:
材料科学
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环境科学
·
理论化学
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2026
·
IF 10.6
Xinlei Zhang,Shiying Yang
The removal of hazardous Cr(III) complexes via advanced oxidation processes can generate highly toxic Cr(VI), posing significant environmental risks. Therefore, there is an urgent need to develop alternative methods that completely suppress the generation of Cr(VI). In this study, with no detectable Cr(VI) in the solution (below the detection limit of 0.004 mg/L), the carbon nanotubes-modified micron-sized zero-valent aluminum (CNTs@mAl 0 ) can effectively remove 99.50% of Cr(III)-EDTA and 83.34% of TOC under the typical acidic conditions of industrial chromium wastewater (pH = 3.00) by activating molecular oxygen. Then the following alkaline precipitation can easily remove the decomplexed free chromium, lowering total chromium concentration to 0.11 mg/L, which meets most national and regional standards, whereas direct alkali precipitation fails to meet them. Serving as a strong electron reservoir (E 0 = - 1.662 V), micron-sized zero-valent aluminum (mAl 0 ) synergizes with highly conductive carbon nanotubes (CNTs) to effectively activate O 2 , facilitating the production of reactive oxygen species (primarily 1 O 2 and •OH) that drive the oxidative decomplexation of Cr(III)-EDTA. Furthermore, the organic ligands are efficiently mineralized, thus preventing Cr(III)’s re-complexation. More interestingly, once the Cr(VI) is possibly generated, it would be rapidly absorbed by CNTs and be immediately reduced by mAl 0 with strong reducing power, thereby completely suppressing the generation of any Cr(VI) in bulk solution. In conclusion, this study presents an environmentally friendly and straightforward treatment system for Cr(III)-complexes, offering an effective solution to mitigate the environmental risks posed by chromium, particularly Cr(VI), in wastewater.
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PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Linheng Chen,Weixi Liu,Yang Wu,Jumei Li,Yibing Ma
There is uncertainty in quantifying the toxic effects of total chromium (Cr) in the environment by modeling the toxicity of individual Cr(III) or Cr(VI). In the present study, the effects of Cr(III) and Cr(VI) on barley root elongation were investigated in a hydroponic system where Cr(III) and Cr(VI) combination dose-response experiments under monotoxicity concentration, single-dose addition, and fixed concentration ratios were designed to identify and quantify their combined phytotoxicity of one element with various valences. The results show that the calculated mixed toxicity unit values for 50% inhibition (TU mix50 ) ranged from 1.06 to 1.45, indicating the weak antagonism effects of Cr(III) and Cr(VI) on barley root toxicity. Also, the single-dose group experiment has proved that the EC 50 of Cr(VI) was increased from 71.2 μM to 119.9 μM with Cr(III) addition, which suggested that Cr(III) has antagonism on the toxicity of Cr(VI). While EC 50 of Cr(III) was not affected by Cr(VI) addition. After introducing the expansion coefficient of Cr(III) on Cr(VI) toxicity, both the extended concentration addition model (e-CA) based on the log-logistic and Weibull equations and the extended independent action model (e-IA) could more accurately predict the barley root elongation under Cr(III) and Cr(VI) interaction. The e-CA model based on the Weibull equation had almost the best correlation coefficient (R 2 ) and lowest root mean square error (RMSE) between the measured and predicted values. Finally, the combined toxicity and antagonism of the same element with co-existing different valences simultaneously were successfully and firstly identified and quantified in the present study.
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PubMed
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Cheng Ye,Xinyu Zheng,Lingmiao Fang,Zhanpeng Fu,Di Li,Jianjun Zhu,Deli Jiang
Designing cost-effective and efficient bifunctional electrocatalysts for overall water splitting is crucial for the production of renewable energy, yet still remains challenging. Herein, we report a bifunctional electrocatalyst assembled from CoMoP nanosheets and Cr(OH)3 nanoblocks via hydrothermal and electrodeposition methods. The strong coupling interface formed between CoMoP and Cr(OH)3 not only induces the formation of d–d orbital hybridization, exposing abundant active sites and improving charge transfer efficiency, but also accelerates the reaction kinetics, forming a stable heterostructure, thereby improving the catalytic activity and stability. Meanwhile, the prepared CoMoP/Cr(OH)3/NF electrode demonstrates overpotentials of 88 mV for the hydrogen evolution reaction (HER) and 207 mV for the oxygen evolution reaction (OER) at 10 mA cm–2. Remarkably, assembled CoMoP/Cr(OH)3||CoMoP/Cr(OH)3 requires only 1.52 V at 10 mA cm–2, outperforming most reported advanced bifunctional catalysts. This study proposes a rapid and rational strategy for constructing novel bimetallic phosphide/hydroxide heterostructured electrocatalysts.
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PubMed
高影响因子
Desalination and Water Treatment
·
2026
·
IF 3.4
Xiaolan Shen,Zhenbo Peng,Jiang Shen,Wenting Si,Ningru Sun,Hao Li,Rui Shen
In this study, a membrane-free electrodeionization (MFEDI) technology was demonstrated first time for the removal of hexavalent chromium (Cr(VI))-containing wastewater. Two packing configurations, namely, layered semimixed packing MFEDI (LSMP-MFEDI), and fully mixed packing MFEDI (FMP-MFEDI), were comprehensively investigated for Cr(VI)-containing wastewater treatment. During the treatment stage, the treatment capacity of FMP-MFEDI (132 h) was twice that of LSMP-MFEDI (60 h), with the effluent conductivity under 1 μS/cm. The enhancement is primarily due to the initial adsorption of dichromate(Cr 2 O 7 2- ) by quaternary amine groups, which promotes the co-adsorption activity of tertiary amines. More importantly, during the electroregeneration stage, FMP-MFEDI (229.7 mg/L) exhibited higher regenerated average Cr(VI) concentrations than LSMP-MFEDI (170.5 mg/L), along with a reduced energy consumption (0.19 kWh/g for FMP-MFEDI, 0.25 kWh/g for LSMP-MFEDI) and an increased water recovery rates (95.6% for FMP-MFEDI, 94.1% for LSMP-MFEDI). Such an enhanced electroregeneration performance in FMP-MFEDI was because that the strong-base and weak-base anion-exchange resins fully interact to form a “contact face”, which comprises both tertiary and quaternary amine functional groups. The tertiary groups promoted the release of Cr 2 O 7 2- from the quaternary groups, thereby showing a synergistic effect in electro-releasing the adsorbed Cr 2 O 7 2- . This provides abundant localized ion-depletion regions, consequently enhancing the electroregeneration property.
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DOI
高影响因子
WATER RESEARCH
·
2018
·
IF 7.051
Guojun Chen,Juncheng Han,Yang Mu,Huimin Yu,Liping Qin
Chromium isotope fractionation analysis is a promising approach for the assessment of microbial Cr(VI) reduction in groundwater. Understanding the mechanisms and other parameters that control Cr isotope fractionation factors (between the product Cr(III) and reactant Cr (VI)) in microbial Cr(VI) reduction is critical to this application. To date, such studies are very limited. Here, the influence of critical factors on observed Cr isotope fractionation during Cr(VI) reduction by Shewanella oneidensis MR-1 under various conditions was investigated. The Cr(VI) concentration and Cr isotope ratio measurements were conducted on unreacted Cr(VI) remaining in solution to determine Cr isotope fractionation factors. The changes in ambient environmental conditions (e.g., pH, temperature) have limited influence on Cr isotope fractionation factors. However, as a result of Cr(VI) consumption as the experiments proceed, the change in bioavailability of Cr(VI) has a significant impact on Cr isotope fractionation factors. For example, in temperature-controlled experiments, Cr isotope fractionation showed two-stage behavior: during Stage I, the values of ε were −2.81 ± 0.19‰ and −2.60 ± 0.14‰ at 18 °C and 34 °C, respectively; during Stage II, as Cr(VI) reduction progressed, Cr isotope fractionation was significantly masked, and the ε values decreased to −0.98 ± 0.49‰ and −1.01 ± 0.11‰ at 18 °C and 34 °C, respectively. Similar two-stage isotope fractionation behaviors were observed in pH-controlled experiments (pH = 6.0 and 7.2) and in experiments with and without the addition of a competing electron acceptor (nitrate). Masking of isotope fractionation in Stage II indicated restrictions on the bioavailability of Cr(VI) and mass-transfer limitations. This study provides an explanation for the variation in Cr isotope fractionation factors during microbial Cr(VI) reduction in the environment, furthering the viability of Cr isotope ratio analysis as an approach in understanding Cr biogeochemical cycling.
研究领域:
环境微生物学
·
同位素地球化学
·
生物修复
·
地球化学
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2022
·
IF 6.633
Min Xu,Xiaoli Ma,Yahui Chen,Luzeng Hu,Bo Wang,Muqing Qiu
Nanoscale zero-valent iron/biochar (nZVI/biochar) has been widely utilized in environmental remediation due to its excellent removal efficiency, easy synthesis, low-cost and environmental friendliness. Herein, the removal and interaction mechanism of Cr(VI) removal on nZVI/biochar was investigated by macroscopic and microscopic techniques. Compared to nZVI (25.84 mg/g), the high removal capacity (63.29 mg/g at pH 4.5), excellent reusability and chemical stability of nZVI/biochar were due to various oxygen-bearing functional groups and synergetic interaction. According to analysis of X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge fine (XANES) and extended X-ray absorption fine structure (EXAFS) spectra, the interaction mechanism of Cr(VI) on nZVI/biochar followed adsorption (complexation, electrostatic interaction), reduction and co-precipitation process with increasing reaction time. These findings are crucial for the application of nZVI/biochar for removal of heavy metals in actual environmental cleanup.
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产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Haoyue Fu,Weixin Qian,Haitao Zhang,Hongfang Ma,Weiyong Ying
Unmodified Cr/Al 2 O 3 and Cr/Al 2 O 3 doping with different alkali metals (Li, Na, K) were prepared by the incipient wetness impregnation method. The surface elements of all the catalysts are evenly distributed and well loaded, and the addition of alkali metals does not change the crystal structure and surface texture. Both Cr 6+ and Cr 3+ species exist on all catalysts, and the addition of alkali metals can increase the amount of Cr 6+ species, and Cr 6+ species are basically converted into active Cr 3+ species in the reaction thus increasing the initial propane conversion in the reaction. The addition of alkali metals reduced the amount of total acid sites and the strong acid sites of the catalyst, thus inhibiting the occurrence of side reactions and the formation of carbon deposition , and reducing the deactivation rate of the catalyst. Cr-0.5Na/Al 2 O 3 exhibited the best catalytic performance and the lowest carbon deposition.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2022
·
IF 11.889
Yu-Nan Zhang,Jian-Zhong Guo,Chunzheng Wu,Wei-Wei Huan,Lin Chen,Bing Li
Chemical modification on hydrochars can significantly improve their ability of removing heavy metal ions from wastewater, but so far no research has focused on the chemical modification through free radical reaction. In this work, a cation functionalized hydrochar (CFHC) bearing − N + H 2 R was synthesized by grafting-polymerization of glycidyl methacrylate (GMA) onto bamboo hydrochar under initiation by benzoyl peroxide, followed by the amination with the introduced epoxy group and diethylenetriamine and a subsequent hydrochloric acid treatment. The resulted CFHC exhibited a superior removal capacity of 424.09 mg·g −1 for Cr(VI), and the highest sorption occurred at pH of 2. Combining a series of characterizations and tests, it was concluded that the sorption conformed to the pseudo-second-order and Freundlich equations, indicating a multilayer chemisorption process that mainly driven by electrostatic reaction, reduction, and surface complexation. This research proved that a free radical polymerization treatment could effectively transform hydrochars into super adsorbents for wastewater treatment.
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DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Qiuyu Cheng,Xin Chen,Lin Liu,Peng Jiang,Deshi Song,M.A. Subramanian
Novel green and blue chromophores based on Ni/Co/Cr doped BaMg 6 Ti 6 O 19 solid solutions are successfully synthesized through a solid-state reaction. The crystal structure of all the samples belongs to the magnetoplumbite structure with the space group of P 6 3 / mmc . The BaMg 6- x /2 Ti 6- x /2 Ni x O 19 (0 ≤ x ≤ 0.3) compounds exhibit a light green ( x = 0.1) to yellow-green ( x = 0.3) color. The oxidation state of Ni is confirmed to be +2 valence and the d-d transition of Ni 2+ in octahedral sites is responsible for color. BaMg 6- x /2 Ti 6- x /2 Co x O 19 (0 ≤ x ≤ 0.3) series show a blue color and the intensity of blueness is increasing with the increase of Co content. The blue color is due to d-d transitions within Co 2+ present in the tetrahedral sites. For BaMg 6- x /2 Ti 6- x /2 Cr x O 19 (0 ≤ x ≤ 2) phases the color varies from light green ( x = 0.2) to green ( x = 2). Chromium exists in +3 and + 6 oxidation states and the observed color is due to charge transfer transition between Cr 3+ –Ti 4+ and d-d transitions within octahedral Cr 3+ sites resulting in strong absorption in the visible region. The synthesized colored oxides are mixed with PMMA to prepare novel green and blue PMMA polymer composites to evaluate their compatibility in plastics.
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高影响因子
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