CHEMOSPHERE
·
2022
·
IF 8.943
Cheng-Feng Liang,Song-Hai Wu,Yu-Le Wang,Zhi Xu,Yong Liu,Hai-Tao Ren,Shao-Yi Jia,Xu Han
Thiosulfate (S 2 O 3 2− ) is an important ligand to complex metal cations, however, the reactivity of metal-thiosulfate complexes has barely been mentioned. In this study, the reactivity of the Cu(II)–S 2 O 3 2− system in the reduction of Cr(VI) was investigated. Kinetic results show that the reduction rates of Cr(VI) decrease with increasing pH values from 3.0 to 5.0, and 94.3% and 97.5% of 10 mg L −1 Cr(VI) was rapidly reduced within 1 min at pH 3.0 and within 30 min at pH 5.0, respectively at the molar ratio of Cu(II):S 2 O 3 2− of 0.05. We rule out the contributions of S species of tetrathionate (S 4 O 6 2− ) and sulfite (SO 3 2− ) to Cr(VI) reduction and point out that the produced Cu(I) in the Cu(II)–S 2 O 3 2− system is the key reductant that mediates the reduction of Cr(VI). We suggest that complexation between Cu(II) and S 2 O 3 2− with the formation of Cu II (S 2 O 3 ) 2 2− is the pre-requisite for the formation of Cu I (S 2 O 3 ) n 1−2n , which plays an important role in Cr(VI) reduction, accompanied by the re-oxidation of Cu(I) to Cu(II) by Cr(VI), achieving the rapid redox cycling of Cu(II)–Cu(I)–Cu(II). Such a redox cycle also mediates the denitrification process of NO 2 − to NH 3 /NH 4 + under weakly acidic conditions. This study enriches our understanding on the reducing reactivity of the Cu(II)–S 2 O 3 2− system and the importance of the Cu(II)–Cu(I)–Cu(II) redox cycle towards environmental oxidizing contaminants.
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DOI
PubMed
高影响因子
ACS ES&T Engineering
·
2022
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IF 0
Jiaxing Yu,Qi Fu,Huangsheng Yang,Junhui Wang,Gangfeng Ouyang,Zhengping Hao
Highly resistant organic pollutants and heavy metals (such as hexavalent chromium (Cr(VI)) usually coexist in industrial wastewater. However, efficient synergistic removal of them is still challenging in practical applications, due to low efficiency and high energy input required for this process. In this study, the metal-free multiwalled carbon nanotubes (MWCNTs) are demonstrated to simultaneously remove bisphenol A (BPA) and Cr(VI) without any external energy or chemical input. In this novel synergistic removal system, the catalytic performance is even higher than those of most of the reported metal-based catalysts in photo/electrocatalytic systems. The catalytic performances are negligibly affected by ions and humid acid, indicating applicability of the catalyst in actual wastewater. In addition, the MWCNT catalyst exhibits good recyclability after thermal treatment under inert atmosphere. Furthermore, the catalytic mechanism of this system has also been comprehensively investigated. This MWCNT-activated synergistic organic pollutants–Cr(VI) elimination system provides a novel and cost-effective strategy of “waste control by waste” for removing multiple industrial contaminants.
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DOI
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 6
·1-10
·
IF 5.479
Li Bo,Ma Hong,Zhang Bo,Qian Jing,Cao Ting,Feng Haitao,Li Wu,Dong Yaping,Qin Wenwu
The authors describe the preparation of carbon dots (CDs) that display both blue (~ 410 nm) and yellow (~ 565 nm) emission peaks. The CDs was synthesized by solvothermal treatment of o-phenylenediamine in aqueous ethyl alcohol at pH ~7.0. The CDs are shown to be useful fluorescent probes for pH values in that the ratio of fluorescences at 565 and 410 nm strongly depends on the pH value in the range from 4.5–6.5 and 10.0–13.0, respectively. The blue fluorescence is quenched by 91% by 100 µM solutions of Hg(II) through an electron transfer process, and is restored by 97% an addition of chloride (0.5 mM). The yellow fluorescence, in contrast, is hardly affected. The ratio of fluorescences at 414 and 565 nm drops linearly in the 30 to 60 μM of Hg(II) concentration range, and the limit of detection is 60 nM. Fluorescence is linearly restored in the 70 to 180 μM chloride concentration range, and the LOD is 2.8 nM. Both the blue and the yellow emission are reduced by Cr(VI) (chromate) due to an inner filter effect at pH 3.0. The ratio of fluorescences (410/565 nm) drops linearly in the 20 to 250 μM Cr(VI) concentration range, and the LOD is 260 nM. The method was utilized to analysis of chloride in salt lake brine and of Cr(VI) in spiked tap water.
Schematic presentation of carbon dots with pH-dependent dual emission (at ~ 410 nm and ~ 565 nm). They are shown to be viable fluorescent probes for ratiometric sensing of pH values, mercury(II), chloride and Cr(VI) via different mechanisms.
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高影响因子
GREEN CHEMISTRY
·
2025
·
IF 9.2
Yating Hou,Xiaoli Sun,Shan Lu,Ningyuan Song,Yanru Liu,Shu Yang,Fangxu Dai,Yunmei Du,Lei Wang
It is a challenge to enable non-precious metal-based electrodes to exceed the ultra-high alkaline HER activity of Pt-based precious metals by constructing a ‘vacancy–dopant structure’ with controllable vacancy concentration. Density functional theory (DFT) calculations revealed that the ‘P vacancy (Pv)–Cr dopant structure’ stimulates a significant enhancement-tandem effect during the alkaline HER process. This enhancement effect is reflected in enhanced conductivity and the adsorption capability of H2O and OH*, thereby reducing the reaction energy barrier. Simultaneously, the tandem effect induces the Cr dopant near Pv as a unique OH* adsorption site, thereby activating the Ni(Pv)–P–Cr(Pv) mechanism that effectively prevents the poisoning of Ni hydrophilic sites and optimizes the alkaline HER pathway. Based on these findings, Cr–NiPv/IF with the ‘Pv–Cr dopant structure’ was innovatively constructed using the ‘phosphorization-quenching’ technique. Interestingly, the quenching temperature difference is positively correlated with the Pv concentration. Under the enhancement-tandem effect of the ‘Pv–Cr dopant composite structure’, Cr–NiPv/IF only requires 240 mV to deliver 1 A cm−2 for alkaline HER, which is 3.04-fold higher than that of Pt/C@IF. This work offers a novel design concept for constructing non-precious metal-based electrodes that surpass the performance of Pt-based electrodes.
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Chuanjin Lin,Yanfei Tang,Jing Sun,Bin Dong,Xu Zuxin
In this study, the remediation effects of two types of sludge (ferric-based flocculant and non-ferric-based flocculant) on Cr(VI)-polluted wastewater were evaluated to clarify the key components in sludge hydrothermal solutions responsible for reducing Cr(VI) and understand the underlying molecular-level transformation mechanisms. The results revealed that the primary reactions during the hydrothermal processes were deamination and decarboxylation reactions. Correlation analysis highlighted proteins, reducing sugars, amino groups, and phenolic hydroxyl groups as the major contributors. In-depth analysis of the transformation process of functional groups within dissolved organic matter (DOM) and synergistic redox process between Cr(VI) and DOM in hydrothermal solutions demonstrated that phenolic hydroxyl and amino groups gradually underwent oxidation during reduction of Cr(VI) by DOM, forming aldehyde and carboxyl groups , among the others. Time-dependent density functional theory calculations revealed notable shift of reducing functional groups from ground state to excited state following iron complexation, ultimately facilitating reduction reaction. Subsequent investigations, including soil column leaching and seed germination rate tests, indicated that synergistic redox interaction between Cr(VI) and DOM significantly reduced waterborne heavy metal and toxic organic pollution. These findings carry substantial implications for sludge treatment and remediation of heavy metal pollution in wastewater, offering valuable insights into effective environmental remediation strategies.
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DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Min Zhuang,Hui Wang,Lu Qi,Liqiang Cui,Guixiang Quan,Jinlong Yan
Biochar-supported nanoscale zero-valent iron (nZVI) has been unitized for the reduction of Cr(VI). However, the low specific surface area of biochar and the surface oxidation of nZVI limit its contaminant removal efficiency . In this study, activated biochar (ABC) was prepared through a self-blowing strategy and was used as a supporter for sulfidated nZVI (S-nZVI@ABC). The results revealed that S-nZVI@ABC had a significantly increased specific surface area (414 m 2 g −1 ) as compared to S-nZVI supported on commercial biochar (S-nZVI@BC, 62 m 2 g −1 ), and the S-nZVI particles were evenly dispersed. Compared with S-nZVI@BC, the reactivity S-nZVI on ABC increased by 23%. The removal efficiency of Cr(VI) by S-nZVI@ABC was also much higher than the content removed by nZVI, nZVI@ABC. The removal efficiency was nearly doubled when the S/Fe was increased from 0 to 0.5. Higher dosage, lower pH value and Cr(VI) concentration led to an increased Cr(VI) removal efficiency. The retention rate of Cr(VI) removal efficiency was higher than 90% after 10 days of aging. S-nZVI@ABC also showed good reusability in the recycling experiment. The removal process of Cr(VI) was classified as an endothermic process and fitted with the Langmuir adsorption isotherm. Multiple interaction mechanisms including reduction, precipitation, and adsorption were involved in the removal of Cr(VI) by S-nZVI@ABC.
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高影响因子
Cleaner Engineering and Technology
·
2021
·
IF 0
Yanjin Zheng,Feng Rao,Meilli Zhang,Jing Li,Wenxuan Huang
Water containing excess heavy metals poses a health risk to humans but can be purified effectively using adsorbents. As such, identifying novel and efficient adsorbents to remove heavy metals such as Pb(II) and Cr(VI) is vital. We report a new metal-organic framework (MOF), {[Cd 1.5 (btc)(bibp)·2H 2 O]·H 2 O}n, capable of capturing Pb(II) and Cr(VI) from water. The adsorbent has a high density of exposed active sites, with maximum adsorption capacities of 537.634 mg/g for Pb(II) (pH = 7) and 787.402 mg/g for Cr(VI) (pH = 6). Adsorption equilibrium was reached after 60 and 120 min with Pb(II) and Cr(VI), respectively, and the adsorbent was regenerated effectively using an ethanol-acetic acid eluent. Analysis of the adsorption kinetics using Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy showed that the abundant –OH groups (hard base) and the Pb(II)/Cr(VI) (soft acid) behave according to the hard-soft acid-base principle. In addition, electron pairs are shared between the imidazole N atoms and Pb(II)/Cr(VI). This study provides new insights into the design of three-dimensional MOFs for removing pollutants from industrial wastewaters, with the potential to mitigate health risks to humans and natural ecosystems.
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DOI
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Beibei Zhao,Jingchun Tang,Honghong Lyu,Feng Liu,Lan Wang
Low molecular weight organic acids with low cost and environmentally friendly characteristics can enhance the electron transfer between materials and contaminants. In this study, oxalic acid (OA), citric acid (CA), and ethylenediaminetetraacetic acid (EDTA) were selected to strengthen ball milled natural FeS 2 /biochar composite (FeS 2 /biochar) for aqueous Cr(VI) removal. 100% of Cr(VI) was removed when 5 mM of OA and 0.25 g·L −1 FeS 2 /biochar were used together. In contrast, the removal rate of Cr(VI) by the individual FeS 2 /biochar and OA was 57.9% and 6.3%, respectively. The experimental and characterization results suggested that OA was adsorbed on the surface of FeS 2 /biochar through the conjugated structure of pine biochar, thereby enhancing the dissolution rate of Fe(II) and S(-II) in the FeS 2 /biochar composite, and facilitating the conversion of Fe(II), S(-II), and Cr(VI) to Fe(III), SO 4 2- , and Cr(III), respectively. In addition, the complexation of OA with Fe(III) and Cr(III) reduced the formation of Fe(OH) 3 and Cr(OH) 3 , exposing more surface active site of FeS 2 /biochar for the reduction of Cr(VI). As an electron donor , the addition of OA enhanced the electron transfer process of FeS 2 /biochar to Cr(VI) on the one hand, and on the other hand promoted the redox cycle of Fe(II) through the electron transfer between OA and Fe ions . FeS 2 /biochar showed better stability even after 5 cycles (in 5 mM OA system). The present study demonstrated the promise of low molecular weight organic acids in strengthening materials for environmental remediation.
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Mao Gao,Fan Tang,Yongchao Zhao,Yixuan Chu,Yan Yang,Guangming Tian,Yanlong Wang,Huaqing Liu
The characteristics of soil pore structure response to electric field strength and their effects on the migration of hexavalent chromium during electrokinetic remediation remain unclear. This paper investigates the effects of soil actual voltage and pore redistribution on hexavalent chromium removal under various voltage gradients during electrokinetic remediation. The electric field across the soil was the dominant factor that affected the soil properties, pore structure, and transportation of hexavalent chromium. The removal efficiency of dissolved hexavalent chromium was significantly enhanced from 36.1 % to 80.5 % as the theoretical voltage gradients increased from 0.5 V·cm −1 to 3 V·cm −1 due to the highest voltage proportion (52.7 %) of the soil chamber at 3 V·cm −1 , while it only increased to 82.0 % at 4 V·cm −1 . The optimal actual electric field strength of 1.00–1.50 V·cm −1 across the soil matrix facilitated the efficient electromigration of hexavalent chromium. The electric field force exerted a direct (0.70) or indirect action intensity (1.55) on soil pore structure by altering soil chemical properties. Soil mesopores and ultra-micropores transformed into micropores through collapsing, shrinking, ion migration, weakening electrostatic repulsion, and enhancing adhesive bonding among particles with increasing electric field. The distribution and structure of soil pores were more homogenous under optimal electric field conditions, thereby improving the migration path of hexavalent chromium. Soil mesopores facilitated hexavalent chromium removal and the formed micropores were opposite. These findings have significant scientific and practical implications for applying the in-situ electrokinetic techniques in the remediation of metal-contaminated soils.
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高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2025
·
IF 4.7
Shaopeng Zhang,Jie Ding,Dayong Tian,Ruochen Lin,Weiming Wu,Chao Liu,Jiaohui Xia,Minghua Lu
Due to their carcinogenicity and persistence, water pollution of heavy metals, particularly chromium (VI), presents a key environmental problem. The attractive properties of a covalent organic framework make it a promising adsorbent for removing pollutants from water. Nevertheless, the lack of diversity and number of functional groups and the insufficient stability of the covalent organic skeleton limit its potential for adsorptive removal of specific metal ions, such as hexavalent chromium Cr(VI). A series of COFs@HPAN composed of protonated hypercrosslinking aniline polymer (HPAN) and COFs were synthesized via Friedel-Crafts reaction of dimethoxymethane with aniline in the presence of COFs. The modification with COFs not only provides HPAN with a higher specific surface area and improves its dispersibility, but it can also result in COFs@HPAN surface rich in functional groups. The structure of COFs@HPAN is verified by different characterization methods, such as FTIR, XRD, SEM, BET, and so on. 1610 cm -1 (-NH 2 ), 1657 cm -1 (C=N), 3388 cm -1 (N-H), and 2904 cm -1 (-CH 2 ) confirms the successful introduction of HPAN at COFs@HPAN. The XRD pattern of COFs@HPAN shows excellent crystal structure with distinct characteristic peaks at 21.1o and 26.8 o . The surface area, pore size, and pore volume of COFs@HPAN are 9.48 m 2 /g, 12.5 nm, and 0.04 cm 3 /g, respectively. SEM image shows COFs@HPAN contains numerous small pores, along with a high surface area and porosity, making it highly effective for Cr(VI) adsorption. The impact of time, initial pH, temperature, initial concentration, and ionic strength on Cr(VI) adsorption capacity was explored through batch tests. The adsorption is spontaneous and endothermic and follows Freundlich's isothermal adsorption and quasi-second-order model, suggesting chemisorption. At 318 K, the highest adsorption capacity of Cr(VI) was 412.26 mg/g. Additionally, COFs@HPAN has good anti-interference and reusability. Except for CO 3 2- , SO 4 2- , and PO 4 3- , the presence of coexisting anions did not significantly affect Cr(VI) adsorption, and the adsorption capacity remained well above 166 mg/g after 10 cycles. Electrostatic adsorption, chelation, and reduction are the predominant processes regulating Cr(VI) removal. XPS analysis demonstrated a nearly 77 % reduction of Cr(VI) to Cr(III) through electron transfer from the electron-donating functional groups such as -NH 2 . The results show that COFs@HPAN have good Cr(VI) adsorption capacity and can be used for the treatment of Cr(VI) in acidic wastewater.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Guona Bai,Xu Wu,Mengqun Li,Zihao Zhao,Mengqing Wang,Xinyu Wang,Jiangang Gao,Zongrui Zhang
To address the synergistic removal of Congo Red (CR) and hexavalent chromium (Cr(VI)) from industrial wastewater, this study proposed an “electrospinning-surface modification” strategy. Using poly(vinyl alcohol-co-ethylene) (PVA-co-PE) as the substrate, a dual-functional composite nanofibrous membrane adsorbent (PVA-co-PE/chitosan (CS)/polydopamine (PDA)) was constructed via CS grafting and PDA coating. The structural and physicochemical properties of the PVA-co-PE/CS/PDA NF membranes were characterized by elemental mapping, spectroscopic analyses, and morphological observation, while batch experiments were conducted to investigate the adsorption behavior and key influencing factors. Results showed that the composite membrane exhibited maximum adsorption capacities of 716.9 mg/g for CR and 264.4 mg/g for Cr(VI), with the adsorption process conforming to the Langmuir monolayer adsorption model and pseudo-second-order kinetic model (dominated by chemical adsorption). After four adsorption–desorption cycles, the membrane retained adsorption capacities of 609.3 mg/g for CR and 224.5 mg/g for Cr(VI), demonstrating excellent cyclic stability. With advantages of simple preparation, strong recyclability, and negligible secondary pollution, the proposed composite membrane serves as a novel, efficient adsorbent for the synergistic advanced treatment of organic dyes and heavy metal ions in complex industrial and holds substantial engineering application value.
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Xinyi Feng,Yuqing Fu,Zhanqiu Tang,Hongyuan Tian,Zhenglong Wu,Weidong Qin
Dichlorvos and Cr(VI) are widespread environmental contaminants that pose significant risks to water quality, ecosystems, and human health. Therefore, the development of rapid, sensitive, and reliable detection methods for these pollutants is critically important. Although various techniques have been employed for the individual detection of these substances, achieving simultaneous and selective detection of both remains a considerable analytical challenge. In this study, iron-doped poly(amidoamine) carbon dots (PAMAM-Fe CDs) were synthesized, exhibiting multiple enzyme-mimetic activities, including peroxidase-, oxidase-, superoxide dismutase-, and catalase-like functions. Notably, dichlorvos and Cr(VI) were found to selectively influence the catalase-like and oxidase-like activities, respectively. Based on these findings, a dual-mode fluorescence and colorimetric sensing platform was developed, enabling rapid, sensitive, and selective detection of dichlorvos and Cr(VI), with detection limits of 1.69 × 10⁻⁵ µg/mL and 0.0418 µM, respectively. The applicability of this platform was validated through analysis of real-world samples, demonstrating satisfactory recovery rates and reproducibility. This work not only establishes a new approach for detecting dichlorvos and Cr(VI) for food safety and environmental monitoring but also provides new insights into designing multienzyme-active nanomaterials with significant practical potential.
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高影响因子
危险品化学品经营许可证（带存储）