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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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
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 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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PubMed
高影响因子
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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PubMed
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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高影响因子
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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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
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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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Shimin Chen,Junnan Han,Zhihuan Li,Zijie Lin,Min Wang,Hucheng Song,Xiaodong Pi,Dongke Li,Linwei Yu,Jun Xu,Kunji Chen
Lithium-carbon dioxide (Li-CO 2 ) batteries using high ion-conductive inorganic molten salt electrolytes, as a kind of promising carbon–neutral technology, have attracted much attention due to the high safety and high energy density. However, sluggish CO 2 reduction reaction (CO 2 RR) and evolution reaction (CO 2 ER) kinetics at cathodes make these batteries losing most of their capacity and power. Here, by engineering the carbon-free three-dimensional (3D) Cr-N-Ru catalysts on silicon nanopillars (Si NP) cathodes, we report a reversible solar photothermal (SPT) molten salt Li-CO 2 battery where solar energy can be efficiently harvested (over 90 % absorption rate from 300 nm to 2500 nm), concentrated and converted to heat. Theoretical simulations support that the 3D Cr-N-Ru catalysts exhibit lower energy barrier and more effectively catalyze the CO 2 RR and CO 2 ER process compared to individual Ru or CrN catalyst. The SPT Li-CO 2 battery shows a reversible cycle lifespan of 83 cycles with lower charge potential (3.2 V) and higher energy efficiency of 72 %, corresponding to ∼ 0.9 V potential gap, than the one using conventional Ru catalysts assembled on Si NP cathode. This battery technology paves the way for developing the next-generation safe and high-energy–density energy storage batteries with carbon–neutral effect.
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高影响因子
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
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