FUEL PROCESSING TECHNOLOGY
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2016
·
IF 3.847
Ting-Ting Zhao,Wen-Zhi Ge,Fen Yue,Ying-Xiong Wang,Christian Marcus Pedersen,Fan-Gui Zeng,Yan Qiao
Lignite showed high capacity for reducing Cr(VI) to Cr(III) and hence removed Cr(VI) from aqueous solution, but the reduced Cr(III) cannot be released from adsorbent afterwards especially under acidic condition. In order to know why Cr(III) ions are immobilized within lignite adsorbent and how to recovery Cr species, the interaction of Cr(III) ions with lignite oxidized by Cr(VI) was studied by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The data obtained from these studies indicate that Cr(III) ions are bonded to oxygenic functional groups in lignite oxidized by Cr(VI) and electrons are delocalized over -O-Cr-O- domain. It is also revealed that the O atoms of C = O and C-O groups in the adsorbent matrix are bonded to Cr(III) ions along with the decrease of electron density, while the O atoms of O -C = O group are along with the increase of electron density. Based on these important structural information, we developed a method to treat Cr-loaded lignite further and to recover the Cr species.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Guang Tian,Xiangxiang Li,Falin He,Shuqi Guo,Yaoyue Wang,Yuze Li,Wansong Zong,Rutao Liu
Chromium (Cr) poses potential threats on human and ecological health through both food and environmental pathways. However, the response mechanisms of Cr to function-related proteins in human subjects and the differential effects in the case of different valence states of Cr are still lacking. Herein, the binding interactions and mechanisms of lysozyme to Cr(III) and Cr(VI) were investigated by isothermal titration microcalorimetry, multi-spectroscopy, enzyme activity assay, and molecular simulations. Our results indicated that the binding of Cr in different valence states with lysozyme was a relatively affinity process and mainly driven by hydrophobic forces. Both Cr species induced the looseness of backbone for lysozyme and the enhancement of hydrophilicity around the backbone microenvironment. Otherwise, the α-helix of lysozyme was decreased with different valence states of Cr, while Cr(III) showed a greater degree of influence and a stronger regularity. Interestingly, no significant changes in the microenvironment around aromatic amino acid residues were observed under the exposure of different valence states of Cr. Differential structural changes of lysozyme resulted in activity alterations. At 80 mg·L −1 of Cr, Cr (VI) reduced the lysozyme activity to 81.44% of the control, while the lysozyme activity was significantly reduced to 24.45% under the exposure of Cr (III). Further molecular docking showed that amino acids near the binding sites of different valence states of Cr with lysozyme were not identical, but the enzyme active site, Asp52, was all within the binding pocket. This study elucidates the differential toxicity effects and interaction mechanisms of Cr in different valence states, and offers a comprehensive strategy for exploring the in vitro responses of toxicants exposure.
研究领域:
环境科学
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毒理学
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生物化学
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分子生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2021
·
IF 3.498
Tian Zhao,Hexin Zhu,Wei Geng,Minmin Zou,Ming Dong,Jie Ying
Propionic acid could efficiently affect the formation of Cr-benzenedicarboxylate metal-organic frameworks (MOFs), giving rise to yielding products with various structures. Generally, nano-sized crystals of MIL-101(Cr) can be prepared with comparatively lower concentration of propionic acid (0.6 M), which possessed high porosity (S BET = 2720 m 2 /g). The hierarchically porous (HP) MIL-101(Cr) was obtained with medium concentration of propionic acid (1.2 M), and micro-rod like crystals of MIL-88B(Cr) was formed in high concentration of propionic acid (1.8 M). Compare to bulk MIL-101(Cr) and nano-sized MIL-101(Cr), HP-MIL-101(Cr) showed much higher uptake of methylene blue (119.1 mg/L) in aqueous. This approach can offer a facile and effective pathway to synthesize stable hierarchically porous Cr-benzenedicarboxylate MOF for the applications in pollutant treatment fields.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Peng Li,Yifei Li,Mengyao Qi,Xia Zhang
In recent years, most of the researches on nanozymes have focused on improving their catalytic activity and direct synthesis, but this task is still very complicated. Bimetallic oxides are particularly popular because of their mixed valence and special structure. In this study, iron-manganese bimetallic oxide nano-cubes (IMBO NCs) were prepared by a rapid and effective solvothermal synthesis technique, and showed excellent oxidase-like activity. The exposure of Cr(III) and Cr(VI) inhibited and enhanced the catalytic activity of IMBO NCs respectively. On this basis, a simple, economical and accurate colorimetric sensor was established by combining with 3,3′,5,5′-tetramethylbenzidine (TMB). Using oxidase activity instead of traditional peroxidase activity to detect Cr(III) and Cr(VI) greatly shortens the detection time. The method has also been successfully applied to the quantitative monitoring of Cr(III) and Cr(VI) in lake water. This study provides theoretical support for the effective design of bimetallic oxide nanozyme activity and can guide the development of accurate detection systems for the analysis of Cr(III) in food and Cr(VI) in environment.
研究领域:
环境科学
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纳米生物学
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2020
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IF 3.333
Jiahong Wang,Min Mao,Saleem Atif,Yao Chen
The presence of widely used chelating agents such as ethylenediaminetetraacetic acid (EDTA) in aqueous solution increases the difficulty of heavy metal removal by the formation of heavy metal chelates. In this study, diethylenetriaminepentaacetic acid (DTPA)-chitosan functionalized magnetic silica (Fe 3 O 4 @SiO 2 /Cs-DTPA) was developed for the removal of Cr(III) and Cr(III)-EDTA. The obtained results from characterization confirmed that Fe 3 O 4 @SiO 2 /Cs-DTPA with the core-shell structure and superparamagnetic properties was synthesized. The maximum theoretical adsorption capacity of Cr(III) and Cr(III)-EDTA chelates on the adsorbents were 39.27 and 22.24 mg/g at 25 °C and pH 4.0, respectively. Adsorption equilibrium of Cr(III) and Cr(III)-EDTA on Fe 3 O 4 @SiO 2 /Cs-DTPA was achieved within 15 min, and the adsorption data fit the pseudo second-order model. The co-existing complex agents (EDTA) and cations (Na + , Ca 2+ , and Mg 2+ ) in the aqueous solution reduced Cr(III) adsorption by the competition with Cr(III) and Cr(III)-EDTA chelate for active groups of the adsorbent. The affinity of the Fe 3 O 4 @SiO 2 /Cs-DTPA for Cr(III) and Cr(III)-EDTA was excellent even at high salt and organic chelates concentration. The Cr(III) adsorption was attributed to surface complexation between Cr(III) and DTPA moieties of the adsorbent, while Cr(III)-EDTA as a whole was adsorbed on the adsorbent by the complexation and electrostatic interaction . Cr(III) saturated Fe 3 O 4 @SiO 2 /Cs-DTPA can be readily regenerated in acid solution and Cr(III) or Cr(III)-EDTA adsorption of regenerated adsorbent exhibits no obvious reduce.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Chengfang Zhang,Zhenyu Song,Chao Li,Qinglong Liu,Jingchun Tang
In the actual polluted environment, the composite pollution system was usually composed of heavy metals and organic pollutants, especially Cr(VI) and chlorophenols often co-existed in industrial wastewater. In this study, a composite material consisting of multilayer graphene carbon shells coated with nZVI (gBC@nZVI) with various excellent properties was applied to deal with the composite system of Cr(VI) and 2,4-dichlorophenol (2,4-DCP) coexisting in the wastewater, and the intrinsic mechanism for the simultaneous removal of heavy metals and organic pollutants was systematically investigated. The results showed that in the composite pollution system (Cr(VI) = 20 mg/L, 2,4-DCP = 15 mg/L), complete removal of Cr(VI) could be achieved in 60 min, while 2,4-DCP achieved 95.2 % removal, with the contribution of oxidative degradation being 76.4 %. It was found that during the efficient adsorption and reduction of Cr(VI) by gBC@nZVI, the generation of the metastable intermediate Cr(V) was verified by probe compounds, electron spin resonance and UV–visible spectroscopy, and further experiments demonstrated that the generation of •OH was closely related to Cr(V) and promoted the oxidative degradation of the coexisting 2,4-DCP. Quenching experiments with the addition of specific scavengers indicated that •OH was the active species directly dominating the oxidative degradation of 2,4-DCP, whereas Cr(V) was indirectly involved in the degradation of 2,4-DCP by promoting the generation of •OH. In addition, the increase of solution pH negatively affected the degradation of 2,4-DCP in the composite polluted system, mainly due to the hindered generation of •OH in the alkaline environment. This work provided theoretical support for the promising application of gBC@nZVI in real environments contaminated with a combination of Cr(VI) and chlorophenols.
研究领域:
环境科学
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水处理技术
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污染控制
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Linqing Liang,Jiahong Wang,Yanxin Zhang
In this study, H 2 O 2 oxidized magnetic mesoporous carbon hollow microspheres (Fe 3 O 4 @void@C@H 2 O 2 ) with core-shell structure, high magnetic properties and abundant oxygen-containing functional groups was synthesized for removal of Cr(III)-EDTA and Cr(III) in high salinity wastewater. Fe 3 O 4 @void@C@H 2 O 2 was synthesized at optimum conditions of H 2 O 2 concentration of 20%, oxidation temperature of 40 °C and oxidation time of 4 h, and the determined adsorption amount of Cr(III)-EDTA and Cr(III) on the adsorbent was 9.72 and 10.53 mg g −1 at pH 4.0 and 25 °C, respectively. Adsorption behavior of Cr(III)-EDTA could be better described by Langmuir isotherm and Cr(III) adsorption followed Freundlich isotherm. Cr(III)-EDTA and Cr(III) adsorption on the adsorbent followed pseudo-second-order kinetics, and adsorption rate of Cr(III) adsorption on the adsorbent is higher than that of Cr(III)-EDTA. Fe 3 O 4 @void@C@H 2 O 2 showed strong affinity for Cr(III) and Cr(III)-EDTA even in high salinity water. Moreover, Fe 3 O 4 @void@C@H 2 O 2 exhibited the high stability in acid solution and Cr(III) saturated adsorbent can be easily regenerated in 0.1 mol L −1 HCl. Cr(III)-EDTA adsorption was described to the surface complexation between the oxygen-containing groups (such as hydroxyl, carbonyl and carboxyl groups) of the adsorbent and Cr(III) in Cr(III)-EDTA, and the hydrogen bonding between oxygen-containing groups of the adsorbent and EDTA of Cr(III)-EDTA, while Cr(III) adsorption on the adsorbent was surface complexation and ion exchange. The results highlighted that Fe 3 O 4 @void@C@H 2 O 2 have great potentials for adsorptive removal of Cr(III) and it's chelate from the high salinity wastewater.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2024
·
IF 4.5
Yuxiao Xue,Deqing Zhu,Jian Pan,Gen Li,Xuewei Lv
In this paper, two types of Ni-Cr bearing composite burdens including SP1 (79% Ni-bearing sinter and 21% Cr-bearing oxide pellets) and SP2 (84% Ni-bearing sinter and 16% Cr-bearing pre-reduced pellets) were used for the more efficient preparation of high-Cr ferronickel . Based on the metallurgical performance characterization, thermodynamic analysis and smelting parameters optimization, the qualified high-Cr ferronickel were prepared by the utilization of the Ni-Cr bearing composite burdens. The recovery rates of iron, chromium and nickel exceed 95%, 90% and 98% whereas their grades are 85.56–85.88%, 7.82–8.02% and 1.59–1.62%, respectively. Compared with SP1, SP2 possesses lower smelting duration, which indicates the appropriate proportioning of Cr-bearing pre-reduced pellets is beneficial for the smelting process. The obtained high-Cr ferronickel consisting of (Fe, Cr) 3 C and (Fe, Cr) 7 C 3 can be used as a low-cost substitute for the conventional raw materials of 200 or 300 series of stainless steel .
研究领域:
冶金工程
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2016
·
IF 3.698
Wenjuan Fan,Junlian Qiao,Xiaohong Guan
A new method for Cr(VI) (0.025–8.00 mg/L) determination based on the reaction of Cr(VI) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solutions was developed. The colorless ABTS reacted with Cr(VI) under strong acidic conditions ([H + ] = 3.0 or 6.0 M) producing a stable colored radical ABTS + , which could be measured spectrophotometrically at 415, 649 or 732 nm. The absorbance increase at these three wavelengths for ABTS + generation were all linear (less than 1.0% deviation) with respect to the amount of added Cr(VI) and the sensitivity were 1.099 × 10 5 , 3.720 × 10 4 , and 4.150 × 10 4 M −1 cm −1 of added Cr(VI) at 415, 649 or 732 nm, respectively. Cr(VI) of 0.025 mg/L below the discharge standard of drinking water could be detected with the method quantitatively and 0.002 mg/L Cr(VI) was determined qualitatively. The molar absorptivity of ABTS + generated was determined to be (3.69 ± 0.01) × 10 4 M −1 cm −1 at 415 nm and the reaction between Cr(VI) and ABTS had a stoichiometric factor of 1:3 in excess of ABTS. The absorbance of generated ABTS + was found to be stable in deionized water or wastewater and Cr(VI) spiked in wastewater could be determined accurately. The ABTS method also had a good anti-interference performance against Co(II) ions. Moreover, the ABTS method could be successfully used in the Cr(VI)-S(IV) system for Cr(VI) determination.
研究领域:
分析化学
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环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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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.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2024
·
IF 5.8
Chaorong Chen,Haiyang Xian,Jing Liu,Qingze Chen,Xiaoliang Liang,Runliang Zhu,Michael F. Hochella
Photochemical and adsorptive reactions occurring at the mineral–water interface are of great importance in controlling the fate and transport of contaminants in nature, but the effects of the mineral surface structure on the interplay of these two processes and the underlying mechanisms remain largely unknown. In this work, two different structurally well-defined hematite nanocrystals were employed to explore the coupled photoreduction and immobilization of Cr(VI) on various facets of hematite under light irradiation. Compared with hematite quasi-nanocubes (HNCs) exposing only {012} facets, hematite nanoplates (HNPs) with exposed {001} and {113} facets exhibited higher immobilization ability for Cr(VI) under light irradiation, indicating that the coupled process of photoreduction and adsorption of Cr(VI) strongly relied on the particularly exposed facets of hematite. X-ray photoelectron spectroscopy measurements indicated that the removed Cr(VI) from solution was mainly immobilized on hematite surfaces in the form of Cr(III) (the reduced products of Cr(VI)). Transmission electron microscopy and electron energy-loss spectroscopy results revealed that the accumulation of Cr species was predominantly on the {113} facets of HNPs and the {012} facets of HNCs. Theoretical calculations show that the work function difference between the {113} and {001} facets was directly linked with the effective separation of photogenerated electron–hole pairs in HNPs, which is beneficial for the reduction of Cr(VI). The results of desorption experiments indicate that the coupling of photoreduction and adsorption processes significantly promotes the long-term immobilization of Cr species and effectively reduces their environmental risks (the desorption of Cr(VI) from the HNP and HNC samples decreased from 35.9% and 33.5% to 0.3% and 1.7%, respectively). Overall, the exposed facets can significantly affect the electron transfer properties of hematite as well as the binding affinity for Cr species, thereby governing the reduction and immobilization behavior of Cr(VI) on various facets of hematite. These results advance our understanding of the speciation and immobilization of redox-sensitive contaminants at the surfaces of semiconducting minerals in nature.
研究领域:
环境科学
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表面化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ziyong Chang,Baili He,Xiaosha Gong,Xiaoyue Qi,Kexin Liu
Preparation of efficient adsorbents is of great significance for the recovery of precious metals from secondary resources. Herein, –NH 2 was successfully grafted on MIL-101(Cr) via hydrothermal reaction to improve the adsorption capacity of Au (Ⅲ) in aqueous solution. MIL-101(Cr)–NH 2 had a huge specific surface area (1016.50 m 2 ‧g −1 ), which can provide more adsorption sites for Au (III). At 298 K, the maximum adsorption capacity of Au (III) by MIL-101(Cr)–NH 2 was 792.43 mg∙g −1 and was higher than that by MIL-101(Cr) (140.83 mg∙g −1 ). The adsorption data was well fitted by Langmuir and pseudo-second-order models, confirming that the adsorption process conformed to single molecule adsorption and chemical adsorption . Mechanism study indicated that the adsorption of Au (III) by MIL-101(Cr)–NH 2 was initiated with electrostatic attraction and promoted by reduction and inner complexation between AuCl 4 - and protonated amino groups. During adsorption, Au (Ⅲ) was reduced to Au (0) and Au (I) by –NH 2 . Density functional theory (DFT) calculation demonstrated that MIL101(Cr)–NH 2 possessed higher binding affinity and more adsorption sites for Au (III) than MIL-101(Cr). Moreover, MIL-101(Cr)–NH 2 exhibited excellent selectivity towards Au (III) and good recyclability, which is promising in the recovery of precious metals.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）