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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高影响因子
ACS ES&T Engineering
·
2022
·
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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Journal of Water Process Engineering
·
2023
·
IF 7
Qiang Qu,Ling Qiu,Ming-Zhuo Li,Guo-Tao Sun,He-Yu Chen,Xiao-Hui Guo
Magnetic biochar was successfully prepared from the waste Zanthoxylum branch and applied for Cr (VI) removal from wastewater. Modification parameters including concentration of iron-containing solution, ratio of Fe (III)/Fe (II), and pyrolysis temperatures were systematically investigated. There was a synergistic effect of synthesis conditions on the porous structure and the form distribution of iron. Based on the adsorption experiments, 900MZB8–1 displayed the best Cr (VI) removal performance (42.68 mg/g). The fitting result confirmed that the Cr (VI) removal reaction was the homogeneous chemisorption , and the predicted maximum removal capacity could reach at 215.44 mg/g. Moreover, the XPS analysis indicated that 79 % of Cr (VI) on adsorbent surface was transformed to Cr (III) by the cooperation of oxygen-containing functional groups and reductive iron. Meanwhile, 900MZB8–1 maintained the eminent removal efficiency of 80.65 % after four regeneration cycles. Additionally, the economic feasibility and practical performance indicated the rich-potential adsorbent for Cr (VI) removal.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Qiong Sun,Bing Han,Kaijing Li,Liyan Yu,Lifeng Dong
Photocatalytic fuel cell (PFC) is a novel energy conversion device that can effectively convert light into chemical energy and then electrical energy, accompanied with the pollutant purification treatment by photocatalytic technology. In this study, the synergetic photocatalytic degradation of organic dye in anode and the reduction of heavy metal Cr(VI) in cathode are carried out in an improved dual-chamber PFC device with TiO 2 and core–shell structured Ag@Fe 2 O 3 nanoparticles as photoanode and cathode materials , respectively. Among different materials, Ag@Fe 2 O 3 shows the highest catalytic activity to the reduction of Cr(VI) with an apparent kinetic constant of 0.058 min −1 , even much better than commercial Pt foil (0.027 min −1 ). From morphology and electrical characterizations, the excellent electrical conductivity of noble metal Ag and suitable conduction band positions between TiO 2 and Fe 2 O 3 lead to a rapid and directional transfer of photoinduced electrons, and the variable valence of Fe(II)/(III) in iron oxide facilitates continuous catalytic reduction of Cr(VI) to Cr(III). Moreover, the addition of H 2 O 2 into anode chamber can significantly accelerate the reactions and electricity output. The radical quenching tests prove that the existence of H 2 O 2 can efficiently increase the production of photoinduced carriers, and more oxidizing species (such as O 2 − and OH) can be produced from the reactions between H 2 O 2 and photoinduced holes or electrons.
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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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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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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Qiulan Li,Dezhi Yang,Yaling Yang
The study presents a spectrofluorimetric method for the determination of Cr(III) based on 2,3-diaminophenazine (DAP) as fluorescent nano sensor. With the peroxidase-mimicking activity of copper-doped carbon dots (Cu-CDs), colorless o -phenylenediamine (OPD) was oxidized to fluorescent DAP in the presence of H 2 O 2 via generation of hydroxyl radicals . The Cr(III) was found to decrease the fluorescent intensity of the Cu-CDs-mediated OPD oxidation system. Cr(VI) species were reduced to Cr(III) by employing 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) as the reductant, and a novel spectrofluorimetric method for the highly sensitive detection of speciation Cr(VI) and Cr(III) was developed. The Cu-CDs nanozyme was prepared from ethylenediaminetetraacetic acid copper disodium salt (Na 2 [Cu (EDTA)]) by one-step pyrolysis method. Under optimal conditions, the fluorescence intensity of DAP is linearly proportional to the Cr(III) ion concentration in the range of 5 × 10 −6 to 1.5 × 10 −4 mol L −1 and the detection limit is 1.2 × 10 −7 mol L −1 . The method has a good anti-interference performance against some metal ions , such as, Hg 2+ , Co 2+ , Cu 2+ , Mg 2+ , Ba 2+ , K + , Mn 2+ , Ni 2+ , Al 3+ , and Fe 3+ . The proposed method was successfully applied in the determination of Cr(VI) and Cr(III) in water samples.
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高影响因子
Frontiers of Chemical Science and Engineering
·
2020
·Vol. 15
·期 3
·538-551
·
IF 3.552
Deng Xiaoyan,Wang Luxing,Xiu Qihui,Wang Ying,Han Hong,Dai Dongmei,Xu Yongji,Gao Hongtao,Liu Xien
In this work, an adsorbent, which we call MnPT, was prepared by combining MnO 2 , polyethylenimine and tannic acid, and exhibited efficient performance for Cu(II) and Cr(VI) removal from aqueous solution. The oxygen/nitrogen-containing functional groups on the surface of MnPT might increase the enrichment of metal ions by complexation. The maximum adsorption capacities of MnPT for Cu(II) and Cr(VI) were 121.5 and 790.2 mg·g −1 , respectively. The surface complexation formation model was used to elucidate the physicochemical interplay in the process of Cu(II) and Cr(VI) co-adsorption on MnPT. Electrostatic force, solvation action, adsorbate-adsorbate lateral interaction, and complexation were involved in the spontaneous adsorption process. Physical electrostatic action was dominant in the initial stage, whereas chemical action was the driving force leading to adsorption equilibrium. It should be noted that after adsorption on the surface of MnPT, Cr(VI) reacted with some reducing functional groups (hydroxylamine-NH 2 ) and was converted into Cr(III). The adsorption capacity declined by 12% after recycling five times. Understanding the adsorption mechanism might provide a technical basis for the procedural design of heavy metal adsorbents. This MnPT nanocomposite has been proven to be a low-cost, efficient, and promising adsorbent for removing heavy metal ions from wastewater.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Li Song,Chunping Su,Hui Li,Huiping Zhao,Rong Chen
To achieve an effective and straightforward method for Cr(VI) removal from industrial wastewater, a composite Bi 2 S 3 /PDA/PEI material (BSPP) was successfully prepared through in-situ polymerization of polydopamine (PDA) followed by chemical grafting with polyethylenimine (PEI) on the surface of Bi 2 S 3 materials for round-the-clock highly efficient Cr(VI) removal from actual industrial electroplating wastewater. Under dark conditions, the maximum adsorption capacity of Cr(VI) by BSPP reaches 780.75 mg/g. Interestingly, when exposed to light, the maximum Cr(VI) removal capacity was further increased to 1333.21 mg/g. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometry (ICP-OES) analyses indicate that BSPP not only reduces Cr(VI) to Cr(III) under light condition, but also facilitates the significant decrease of total chromium content. Notably, under natural sunlight exposure outdoors, BSPP is capable of completely eliminating Cr(VI) from both plating cleaning solutions and waste plating solutions. More importantly, BSPP maintains its original Cr(VI) removal efficiency after nine cycles within plating cleaning solutions and six cycles within waste plating solutions. Large-scale testing results indicate that BSPP can effectively treat substantial volumes of electroplating wastewater to comply with national Cr(VI) discharge standards. These findings suggest that BSPP represents a promising material for continuous 24-hour Cr(VI) treatment in industrial electroplating wastewater.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Shuyu He,Shaohua Chen,Liwen Zhang,Shanyi Tan,Huizi Wen,Luyao Xi,Xiangru Zuo,Dongyun Du
Dissimilatory iron-reducing bacteria (DIRB) offer an eco-friendly approach to address nanoscale zero-valent iron (nZVI) surface passivation problem, yet their efficacy is limited by the slow direct extracellular electron transfer (EET) between DIRB and Fe(III) oxide passivation layers (Fe( III )OPL). This study demonstrates that natural dissolved humic substances (DHS)-mediated electron shuttling unlocking nZVI reactivity in Shewanella oneidensis MR-1 (MR-1) system for enhance Cr(VI) removal. Seven DHSs from diverse sources were evaluated, revealing that Cr(VI) removal rate constants ( k obs ) correlate strongly with DHS's quinone content (C=O) and electron transfer capacity (ETC), quantified as k obs = 1.66 C C = O − 9.39 ( P < 0.0007) and k obs = 19.37 ETC + 0.74 ( P < 0.0005). DHS-mediated systems achieve 2.0–12.1-fold higher k obs than nZVI/MR-1 alone. The enhancement mechanism of DHS-mediated Cr(VI) removal by nZVI/MR-1 is that DHS effectively facilitates Fe( III )OPL dissolution on the nZVI surface via electron shuttling, maintaining nZVI reactivity and amplifying Fe(II) generation by 1.65-fold. Moreover, DHS stimulates MR-1 to secrete more extracellular polymeric substances (EPS), enhancing Cr(VI) adsorption and reduction. This work elucidates DHS's dual role in maintaining nZVI activity and amplifying Cr(VI) removal by nZVI/MR-1, while establishing a predictive framework linking DHS molecular traits parameters to Cr(VI) removal kinetic, offering sustainable strategies for heavy metal-contaminated water bodies remediation by integrating biogeochemical and material engineering principles.
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ENVIRONMENTAL RESEARCH
·
2026
·
IF 8.2
Haidong Li,Yuankun Yang,Han Song,Yi Yang,Hui Gong,Xinwen Chen,Weiguo Tu,Xuemei Luo,Yu Liu,Shu Chen
Potassium butyl xanthate (PBX) is a widely used flotation collector that can persist in tailings waters and may generate toxic by-products. In sunlit tailings ponds, sulfite (S(IV)), Cr(VI), and PBX may coexist under certain conditions, yet the impact of coupled S(IV)-Cr(VI) photochemistry on PBX attenuation remains unresolved. We quantified PBX degradation in a sunlight/S(IV)/Cr(VI) system across pH 3-10, covering tailings-water variability and pH-driven speciation. The process enabled simultaneous PBX removal and Cr(VI) detoxification, with optimum performance at mildly acidic-neutral pH. At pH 6, k obs increased from 3.9×10 -3 min -1 (sunlight) to 2.35×10 -2 min -1 (sunlight/S(IV)) and 3.38×10 -2 min -1 (sunlight/S(IV)/Cr(VI)), confirming synergy. Quenching/probe tests and time-resolved EPR implicated SO 4 •− , •OH, and Cr(V), indicating pH-dependent coupling between the sulfite radical chain and the Cr(VI)/Cr(V)/Cr(III) cycle. DFT and LC-MS showed acidic hydrolysis/self-decomposition of PBX to CS 2 at pH 3, whereas near-neutral conditions favored radical/Cr(V)-mediated oxidation with efficient Cr(VI) reduction. Outdoor natural-sunlight tests using laboratory-generated flotation wastewater prepared from raw ore collected from the mine (with spiked S(IV) and Cr(VI)) achieved 90% PBX removal within 60 min at pH = 6, T ≈ 35-36 °C and solar irradiance ≈ 750-850 W m -2 ,indicating preliminary feasibility of the coupled process in a scenario-based flotation-wastewater matrix.
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CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Luzi Yuan,Qingliang Zhao,Ruiyuan Xue,Liangliang Wei,Guangzhi Wang,Jing Ding,Junqiu Jiang,Kun Wang
Groundwater contaminated with toxic metals and petroleum hydrocarbons presents long-term risks due to the different transport and removal mechanisms of these contaminants. Co-occurrence of hexavalent chromium (Cr(VI)) and benzene (C 6 H 6 ) is particularly challenging, requiring combined redox transformation and hydrophobic adsorption for effective remediation. In this study, a porous and mechanically robust permeable reactive barrier (PRB) material, composed of sodium alginate, nanoscale zero-valent iron, and activated carbon (SA–nZVI–AC) was synthesized using a combined sol–gel and freeze-drying method. Unlike conventional nZVI systems that primarily focus on metal reduction, this composite integrates polymer stabilization, carbon adsorption, and iron-mediated redox for simultaneous removal of mixed metal–organic pollutants. Freeze-drying proved to be a key processing step, improving structural integrity, anti-clogging capacity, and thus long-term applicability of nZVI-based PRBs. Material characterization revealed a mesoporous framework, stabilized iron phases, and abundant oxygen-containing functional groups. Batch experiments demonstrated efficient simultaneous removal of Cr(VI) and C 6 H 6 , with adsorption kinetics following pseudo-second-order models ( k 2 values for total Cr and C 6 H 6 were 0.50 and 0.06 g mg −1 min −1 , respectively) and isotherms fitting the Langmuir model. Removal efficiencies exceeded 95.28% for Cr(VI) and 85.11% for C 6 H 6 at pH 7–9 and remained high (>78.15% and > 91.31%, respectively) under interfering ions. Column experiments confirmed sustained contaminant attenuation with breakthrough delayed to approximately 60 days. Cr(VI) was immobilized within the barrier through coupled adsorption and reduction, while C 6 H 6 was effectively retained via physical adsorption within the PRB matrix. Post-column microbial analyses suggested secondary biochemical interactions within the PRB. These results demonstrate that freeze-dried SA–nZVI–AC functions as a coupled adsorption–reduction–immobilization system, showing strong potential for long-term PRB applications in remediating groundwater co-contaminated with metals and organic compounds.
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