CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Mithun Nath,Shengqiang Song,Hang Liu,Yawei Li
Despite huge potential, Al 2 O 3 –CaO–Cr 2 O 3 system has been one of the least investigated one due to the generation of carcinogenic and toxic Cr(VI) compounds. Herein, we investigated the system under air atmosphere varying Cr 2 O 3 while keeping Al 2 O 3 :CaO ratio constant in order to identify the Cr(VI) dominant region, eventually to avoid it. The Ca 4 Al 6 Cr VI O 16 phase predominantly formed in the air atmosphere with Cr 2 O 3 content up to ∼12 mol%. However, an unprecedented Cr(III) phase appeared under air at higher Cr 2 O 3 content (26.43 mol%). We then synthesized the new polycrystalline ternary Cr(III) compound (CaAl 2 Cr 2 O 7 ) at 1500 °C under air atmosphere for the first time. A trigonal symmetry of hexagonal crystal family with space group P3 (143), lattice parameters a = b = 7.7909 Å and c = 7.6506 Å were determined from the X-ray powder diffraction pattern study. Electron microscope studies revealed uniform hexagonal microcrystals with similar lattice parameters. Most significantly, the binding energies of 586.1 and 576.2 eV for Cr2p 1/2 and Cr2p 3/2 respectively implied the +3 oxidation state of Cr in this compound.
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高影响因子
ANALYTICAL SCIENCES
·
2017
·Vol. 33
·期 8
·963-967
·
IF 1.228
Sui Ning,Liu Fengya,Li Tailing,Wang Lina,Wang Tao,Liu Manhong,Yu William W.
Au nanoparticles (AuNPs) dispersed in water were stabilized by tripolyphosphate (P 3 O 10 5- ). When Cr 2 O 7 2- (Cr(VI)) was present, the AuNPs did not change; when Cr 3+ (Cr(III)) was present, the AuNPs would aggregate because of cooperative metal-ligand reaction. Aggregated AuNPs showed different color from the non-aggregated ones. Thus, a simple colorimetric assay was made using AuNPs-Cr(VI) to detect ascorbic acid (AA). Upon introducing AA to the AuNPs- Cr(VI) system, Cr(VI) was reduced to Cr(III), and the aggregation of AuNPs occurred. This colorimetric assay performed high selectivity and a linear concentration response in the range of 0.2 to 10 μM; its limit of detection was 0.15 μM.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Ningyi Chen,Bingcai Pan
Toxic metal-organic complexes are ubiquitous in contaminated waters but more challenging than free ion counterparts for water decontamination. Currently, almost all the available analytical methods, including Au nanoparticles-mediated colorimetric assay, cannot discriminate metal-organic complexes from the total metal content, which greatly impedes the development of specific decontamination strategies for metal-organic complexes. In this study, we found that nitrilotriacetic acid (NTA) functionalized AuNPs could be used to determine various Cr(III) complexes (Cr(III)-lactate, Cr(III)-malonate, Cr(III)-oxalate, Cr(III)-tartrate, Cr(III)-citrate and Cr(III)-EDTA) in water. Mechanism study indicated that at acidic pHs (pH = 1.6), the protonation of organic ligands resulted in partial dissociation of Cr(III) from the corresponding complexes to expose its accessible orbitals for re-coordination with NTA. Such re-coordination induces the aggregation of the dispersed NTA-AuNPs and thereafter causes considerable changes both in color and UV–Vis spectrum of the solution. The nanosensor is highly selective to Cr(III)-organic complexes with detection limits of 0.029 μM for Cr(III)-lactate, 0.043 μM for Cr(III)-malonate, 0.35 μM for Cr(III)-oxalate, 0.079 μM for Cr(III)-tartrate, 2.58 μM for Cr(III)-citrate and 0.90 μM for Cr(III)-EDTA, respectively. The feasibility of the proposed colorimetric assay has been verified by using the authentic natural and industrial water samples. We believe this study will be of fundamental significance to push forward the application of Au NPs colorimetric assay in authentic waters contaminated by toxic metals.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Guang Tian,Falin He,Xiangxiang Li,Shaoyang Hu,Xingchen Zhao,Shuqi Guo,Tingting Wang,Hao Wang,Wansong Zong,Rutao Liu
Chromium (Cr) poses a high ecological risk, however the toxic mechanisms of Cr in different valence states to soil organisms at cellular and molecular levels are not exactly. In this study, the Eisenia fetida coelomocytes and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) were chosen as the target subjects to investigate the effects and mechanisms of cellular toxicity induced by Cr(VI) and Cr(III). Results indicated that Cr(VI) and Cr(III) significantly reduced the coelomocytes viability. The level of reactive oxygen species (ROS) was markedly increased after Cr(VI) exposure, which finally reduced antioxidant defense abilities, and induced lipid peroxidation and cellular membrane damage in earthworm coelomocytes. However, Cr(III) induced lower levels of oxidative stress and cellular damage with respect to Cr(VI). From a molecular perspective, the binding of both Cr(VI) and Cr(III) with Cu/Zn-SOD resulted in protein backbone loosening and reduced β-Sheet content. The Cu/Zn-SOD showed fluorescence enhancement with Cr(III), whereas Cr(VI) had no obvious effect. The activity of Cu/Zn-SOD continued to decrease with the exposure of Cr. Molecular docking indicated that Cr(III) interacted more readily with the active center of Cu/Zn-SOD. Our results illustrate that oxidative stress induced by Cr(VI) and Cr(III) plays an important role in the cytotoxic differences of Eisenia fetida coelomocytes and the binding of Cr with Cu/Zn-SOD can also affect the normal structures and functions of antioxidant defense-associated protein.
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高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Xiao Dan Sun,Zhangxin Duan,Jingjing Song,Hanxing Yang,Kai Yan,Zhenhua Tian,Dangge Gao,Jianzhong Ma
Carcinogen Cr(VI) is reduced efficiently into Cr(III) by a photocatalyst, but the produced Cr(III) is difficult to transfer from the photocatalytic active site. The “two birds with one stone” strategy is proposed to realize the in situ growth of ZnIn2S4 nanoplates on SBA-15 and the creation of separated active sites, in which ZnO loading on the porous SBA-15 nanorod was used as a zinc source. Obtained samples ZnIn2S4/SBA-15 (ZIS/SBA) showed the redshift of the absorption band and better separation of photoinduced carriers than pristine ZnIn2S4, due to its smaller size and S defect. All of the Cr(VI) was reduced to Cr(III) by the ZIS/SBA sample during the photocatalytic process, which was 2 times higher than pristine ZnIn2S4. Moreover, 92.8% of Cr(III) was adsorbed simultaneously during photocatalysis due to the electrostatic interaction from SBA-15. In addition, the ZIS/SBA sample showed good recycling stability after 5 times cycles, providing a new strategy for the in situ growth of ZnIn2S4 on the surface of porous materials and a novel way for the simultaneous removal of Cr(VI) and Cr(III) during photocatalysis.
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高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2019
·
IF 3.261
Zhengquan Liu,Lan Yang,Min Chen,Quansheng Chen
In this work, a label-free fluorimetric method for sensitive and selective detection of Cr(III) was developed by utilizing NaY/GdF 4 :Yb,Er upconversion nanoparticles (UCNPs) and citrate-modified silver nanoparticles (Cit-AgNPs) mixed system. The photophysical and morphological properties of the prepared UCNPs were characterized by various spectroscopic and microscopic techniques. The fluorescence of amino-modified UCNPs can be quenched due to the Cr(III) induced aggregation of Cit-AgNPs by means of inner filter effect. The observed quenching in the fluorescence intensity of the UCNPs is found to be dependent on the concentration of Cr(III). The fluorescence decreases linearly within the investigated concentration of 0.5–40 μM Cr(III) with a limit of detection 34 nM. The practical applicability of the present sensing method is ascertained by detecting Cr(III) in spiked tap water and instant tea samples.
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高影响因子
MICROCHEMICAL JOURNAL
·
2026
·
IF 5.2
Guo Chen,Guang-Zhen Wan,Juan Chen
The escalating global consumption of Traditional Chinese Medicine (TCM) necessitates robust quality control, particularly against contaminants like highly toxic hexavalent chromium (Cr(VI)), which must be distinguished from its essential trivalent counterpart (Cr(III)). In this study, a novel nanozyme-based colorimetric assay is presented for chromium detection, utilizing a zeolitic imidazolate framework-67 encapsulated iron-quercetin nanocomposite (Fe-QueNPs@ZIF-67). The core-shell nanostructure was synthesized through a facile one-pot method at room temperature, in which the ZIF-67 shell served as a sacrificial template to prevent agglomeration of the core Fe-QueNPs, thus preserving their intrinsic catalytic activity. In a buffer medium, the ZIF-67 framework disassembled, uniform dispersing Fe-QueNPs uniformly and releasing Co 2+ ions. A bimetallic complex was formed through synergistic coordination of Co 2+ with Fe 3+ and quercetin ligands, significantly enhancing the peroxidase-like activity of nanozyme. This improved catalytic activity promoted the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H₂O₂. Importantly, a differential response to chromium species was observed: the catalytic reaction was inhibited by Cr(III), leading to signal reduction, whereas it was promoted by Cr(VI), resulting in signal amplification. This dual-response modulation enabled selective and sensitive quantification of Cr(III) (linear range: 10–1000 μM, LOD: 8.8 μM) and Cr(VI) (linear range: 0.5–70 μM, LOD: 0.36 μM). The method was successfully applied to TCM samples, achieving excellent recoveries (95–105%). This work provides a robust and sensitive platform for chromium speciation, offering a promising tool for quality control of herbal medicines and broader environmental monitoring.
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INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Mianmian Wu,Nan Li,Shixiang Zuo,Wenjing Shen,Guifang Sun,Qingfei Li,Minghao Shi,Jiangquan Ma
Piezocatalysis is a promising technology to address environmental pollution by converting mechanical energy into chemical energy. Herein, MoSe2 nanosheets with different 1T phase percentages (ranging from 30 to 80%) were constructed by adjusting hydrothermal temperature. Moreover, the roles of phase engineering in the piezocatalysis were thoroughly investigated by degrading rhodamine B and reducing Cr(VI) in ultrasonic vibration conditions. In particular, MoSe2 prepared at 220 °C (MoSe2-220) exhibits ultrahigh observed constant kobs and degradation rate k, which is superior to most reported catalysts to date. The experimental results indicate that the introduction of the 1T phase increases the active sites of the material, improves the conductivity, and inhibits the recombination of electrons and holes. Moreover, an internal electric field in the 2H phase induced by piezoelectric polarization is facilitated to separate electron–hole pairs, enabling the degradation and reduction to proceed. The capture experiments and EPR tests further confirm that •O2– and •OH are main reactive species, and a rational mechanism is finally put forward. This study offers a clear understanding of phase engineering in piezocatalysis and provides an efficiency strategy to construct highly efficient piezocatalysts.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Wei Zhang,Qiao Li,Rui Li,Nan Shen,Jiansheng Li,Jinyou Shen,Xiuyun Sun,Weiqing Han
Industrial wastewater containing organic ligands and heavy metals is considered a serious public health threat, and its treatment and purification have become challenging tasks. Moreover, the organic-chelated heavy metals formed by common organic ligands and free heavy metals can cause many problems and concerns because of their poor biodegradability, high solubility, and extreme stability. In this study, aluminum-containing ferrihydrite (Fh-Al) adsorbents of different composition molar ratios were prepared and utilized to remove typical EDTA-Cr(III) in an aqueous system, and the associated removal mechanism was examined. The experimental results show that adding Al not only enhances the removal rate of EDTA-Cr(III) by the Fh-Al adsorbent in a wide pH range (pH = 3–9) but also increases the maximum adsorption capacity of EDTA-Cr(III). In addition, the specific surface area of Fh-Al can be increased by adding aluminum with different molar ratios, thus promoting its adsorption performance for EDTA-Cr(III). Furthermore, surface complexation and electrostatic attraction were proposed as possible mechanisms of EDTA-Cr(III) adsorption by Fh-Al. This study shows that Fh-Al-6 adsorbent can adsorb common EDTA-chelated heavy metals (such as EDTA-Pb, EDTA-Cr, EDTA-Cu and EDTA-Cd) in one step, with maximum adsorption capacities of 41.47, 32.33, 16.51 and 31.27 mg/g at pH = 3. The Fh-Al-6 adsorbent can be reused after being regenerated in a 2 g/L Na 2 SO 4 solution. This study provides new expectations for treating wastewater containing organic groups and heavy metals.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2020
·
IF 4.872
Jiahong Wang,Yao Chen,Tongtong Sun,Atif Saleem,Chuanyi Wang
A novel amino-functionalized magnetic adsorbent (Fe 3 O 4 @C@DETA) was developed for adsorption of Cr(III) and Cr(III)-EDTA from wastewater. Fe 3 O 4 @C@DETA were successfully prepared by modification of Fe 3 O 4 @C with diethylenediamine (DETA), which exhibits a core-shell structure and sufficient saturation magnetization. Fe 3 O 4 @C@DETA exhibits much better adsorption performance for Cr(III) and its chelates than the Fe 3 O 4 @C because of newly introduced amino active sites. The enhanced adsorption capacity of Fe 3 O 4 @C@DETA for Cr(III) is 44.74 mg g −1 (at 25 °C and pH 3.0), which is due to the surface coordination with the newly introduced amino functional sites. The Cr(III)-EDTA anions as a whole was adsorbed through the electrostatic interaction with protonated amino species of the Fe 3 O 4 @C@DETA and have maximum adsorption capacity of 47.27 mg g −1 (at 25 °C and pH 3.0). The adsorption data of free and EDTA coordinated Cr(III) were followed the Langmuir equation, while the adsorption dynamics was well explained by pseudo second order model indicating the chemical nature of adsorption process. The higher concentration of Ca 2+ ions in the wastewater compete for adsorption sites and inhibit the Cr(III) removal, while on other hand Ca 2+ ions promotes the adsorption of Cr(III)-EDTA, because of electrostatic interaction with adsorbent active sits. Furthermore, the adsorbent can be easily separated by external magnetic field and regenerated in acidic solution. The adsorbent is stable, recyclable and have more than 75% regeneration efficiency and can be repeatedly used in the adsorption process.
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ACS Applied Nano Materials
·
2019
·
IF 0
Yi Feng,Qian Chen,Mengjue Cao,Nan Ling,Jianfeng Yao
Defect engineering and surface chemistry are closely related to the performance of materials. In this work, the effects of Zr precursors and Ti substitution on the photocatalytic performance of UiO-66-NH2 are studied and analyzed from the perspective of defect engineering and surface chemistry. The findings show that when using ZrOCl2·8H2O as the Zr precursor combined with the postsynthetic treatment of Ti substitution, sample U-OCl-Ti shows significant improvement in Cr(VI) adsorption (20.9 mg/g) and photocatalytic reduction of Cr(VI) under visible light. The improvement can be attributed to the highly defective framework and more -NH2 groups exposed on the surface; therefore the highest light absorption and lowest recombination rate of photogenerated electron–hole pairs are observed in U-OCl-Ti. The findings in this study contribute to a better understanding of how defects and surface chemistry affect the photocatalytic performance, thus providing some designing knowledge for the synthesis of UiO-66 or UiO-66-NH2 with high photocatalytic performance.
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CATALYSIS LETTERS
·
2015
·Vol. 145
·期 10
·1913-1921
·
IF 2.307
Wu Jing,Zhi Yunfei,Shan Shaoyun,Su Hongying,Wu Shuisheng,Jia Qingming
Abstract Polypyrrole(PPy) supported Cr(III)(salen)Cl catalyst was prepared for alternating copolymerization of cyclohexene oxide and carbon dioxide. The supported catalyst and the copolymerization products were characterized by FTIR, XRD, XPS, ICP-MS, SEM, TEM, NMR, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. After the study, we concluded that the homogeneous Cr(III)(salen)Cl is successfully supported on the PPy, and its catalytic performance is much better than the homogeneous one. Moreover, the copolymerization product catalyzed by PPy-Cr(III)(salen)Cl exhibits higher molecular weight, narrower molecular weight distribution, superior thermal stability and selectivity. Graphical Abstract
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危险品化学品经营许可证（带存储）