Journal of Environmental Sciences
·
2020
·
IF 4.302
Kai Liu,Fangbai Li,Qingwen Tian,Chengrong Nie,Yibing Ma,Zhenlong Zhu,Liping Fang,Yuanying Huang,Siwen Liu
Paddy soil and irrigation water are commonly contaminated with hexavalent chromium [Cr(VI)] near urban industrial areas, thereby threatening the safety of agricultural products and human health. In this study, we develop a porous and high specific area bone char (BC) to support nanoscale zero-valent iron (nZVI) and apply it to remediate Cr(VI) pollution in water and paddy soil under anaerobic conditions. The batch experiments reveal that BC/nZVI exhibits a higher removal capacity of 516.7 mg/(g•nZVI) for Cr(VI) than nZVI when normalized to the actual nZVI content, which is 2.8 times that of nZVI; moreover, the highest nZVI utilization is the nZVI loading of 15% (BC/nZVI15). The Cr(VI) removal efficiency of BC/nZVI15 decreases with increasing pH (4 – 10). Coexisting ions (phosphate and carbonate) and humic acid can inhibit the removal of Cr(VI) with BC/nZVI15. Additionally, BC exhibits a strong advantage in promoting Cr(VI) removal by nZVI compared to the widely used biochar and activated carbon. Our results demonstrate that reduction and coprecipitation are the dominant Cr(VI) removal mechanisms. Furthermore, BC/nZVI15 shows a significantly higher reduction and removal efficiency as well as a strong anti-interference ability for Cr(VI) in paddy soil, as compared to nZVI. These findings provide a new effective material for remediating Cr(VI) pollution from water and soil.
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高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Jing Li,Mingjie Fan,Miao Li,Xiang Liu
The excellent potential of nanoscale zero-valent iron (nZVI) makes it a promising remedy for contaminated aquifers. More efficient remediation modes with nZVI have been investigated recently to overcome the inherent drawbacks of materials. In this study, a double surfactant-modified synthesis method is established to make the removal of Cr(VI) more efficiency. A specific focus of the materials status (suspension or powder) is devoted to explore the best application condition, especially for groundwater remediation . A non-ionic surfactant, polyvinylpyrrolidone (PVP), and an anionic surfactant, sodium oleate (NaOA), were selected to modify nZVI simultaneously. The kinetics and isotherm experiments, reactions at different pHs, initial concentrations, gas conditions, and coexisting ion conditions were conducted to analyse the removal mechanism. The characterizations before and after the reaction were used to further explain the results. From the batch experiments, a synergistic effect could be recognized in Cr(VI) elimination when PVP and NaOA were both used for nZVI modification. The materials in suspension (without drying process) exhibited higher removal efficiency in comparison with powder ones. These reactions happened in acidic condition demonstrated higher reactivity. The anaerobic condition facilitated the reaction, which showed prospect application in groundwater. Equilibrium could be reached within 2 min using the suspension sample with a removal efficiency above 99.5% and a maximum removal amount of 231.75 mg g −1 . The reaction process was well-fitted with pseudo-second-order kinetics and the Langmuir model. Cr(VI) was fully transformed into Cr(III), a safer status. These results show this is a promising in-situ method to eliminate Cr(VI) pollution in groundwater.
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Journal of Environmental Chemical Engineering
·
2026
·
IF 7.2
Hongyan Pan,Boyu Du,Wenya Lei,Jiarui Xiao,Nianyi Zao,Xianjin Qi,Yongkui Li
Arsenic contamination presents a serious risk to both ecosystems and human health worldwide. Adsorption has emerged as an economical and effective method for treating arsenic‑laden wastewater. In this study, a nano‑zero‑valent iron adsorbent (CS‑nZVI‑PVP) was prepared using leachate from industrial copper slag as the iron source, and the effect of polyvinylpyrrolidone (PVP) addition on the adsorbent’s morphology and adsorption performance was systematically investigated. Batch experiments demonstrated that CS‑nZVI‑PVP achieved an arsenic removal efficiency of 99.64% with a maximum adsorption capacity of 1066 mg/g, reaching equilibrium within 45 min. Analysis of adsorption isotherms, kinetics, and thermodynamics indicated that the adsorption process follows a multilayer model and is spontaneous and endothermic. The adsorbent also exhibited excellent reusability, maintaining high performance over five consecutive adsorption–regeneration cycles. Mechanistic studies revealed that arsenic removal proceeds through the synergistic actions of surface complexation, electrostatic attraction, and coprecipitation. This work not only advances the resource‑oriented utilization of industrial waste but also offers an efficient and low‑cost strategy for designing adsorbents to remediate arsenic‑contaminated water.
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WATER RESEARCH
·
2025
·
IF 12.4
Bo Chen,Shichao Cai,Liwei Yang,Dong Cheng,Yuhan Hang,Liyuan Liang,Bo Fan,Tianming Chen,Feng He
Stabilized nanoscale zero valent iron (nZVI) is commonly used as a reductant during groundwater remediation of halogenated hydrocarbons. However, humic acid (HA) in groundwater can affect the environmental behavior of nZVI during contaminant degradation. This study investigated the effects of HA on carboxymethyl cellulose-stabilized nZVI (CMC-nZVI) by studying hydrogen evolution, Fe 0 corrosion and carbon tetrachloride (CT) degradation kinetics. The results show that, during the early stage (≤ 24 h), low-concentration HA (HA/CMC-nZVI: 2–8) enhanced the hydrogen evolution reaction (HER) of CMC-nZVI up to 1.36 fold by forming Fe 2 + -HA complexes that prevented passivation. In contrast, high-concentration HA (mass ratio: 24) inhibited HER during the entire reaction period, as HA rapidly and directly consumed Fe 0 from the start of the reaction (final Fe 0 consumption by HA: 62.0 %). In this study we also developed a modified differential HER approach to quantitatively determine HA-induced Fe 0 consumption. This confirmed that quinone moieties in HA compete for electrons and are reduced to hydroquinones, thereby consuming Fe 0 . In CT degradation, HA accelerated the initial reaction (rate constant k CT increased from 0.010 min −1 to 0.038 min −1 ) but significantly reduced electron efficiency (from 6.4 % to 1.3 %) and material longevity at HA/CMC-nZVI ratio of 2–24. Due to HA-mediated depletion of CMC-nZVI, the residual Fe 0 had limited capacity for CT degradation after 24 h. The column experiments further confirmed this adverse effect of HA. However, the coexisting ions in actual groundwater were found to mitigate the Fe 0 consumption induced by HA. This study reveals HA's dual role in CT remediation: initially HA enhances ZVI reactivity, but subsequently HA reduces ZVI reactivity due to electron competition. This provides novel insights for the optimization of ZVI dosing in groundwater remediation.
研究领域:
环境科学
·
纳米技术
·
地下水修复
·
化学工程
·
环境化学
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ACS ES&T Water
·
2024
·
IF 4.8
Zhi Ye,Yunpeng Liu,Jiang Xu,Nan Xu,Juncai Dong,Haijun Chen,Dongrui Li,Lei Peng,Yuxi Gao,Jiating Zhao
The efficiency and stability of in situ remediation of Cr(VI) contamination in underground water and soil are still challenging. In this study, a green tea (GT) synthesized nano-zerovalent iron (nZVI) nanocomposite supported by diatomite (DE) (nZVI@GT/DE) via tea polyphenols was designed. The synergetic effect of DE support and tea polyphenols wrapping increased the Fe(II) component in nZVI@GT/DE and its transportability. Compared to nZVI@GT/Mont (supported by Mont with sandwich structure), nZVI@GT/DE exhibited a notably higher capacity (>100 mg g–1) for immobilizing Cr(VI) and a more pronounced ability to release iron ions in solution (corrosion parameter: K ≈ 1.046). This was attributed to the combined effect of the unwrapping process of tea polyphenols coverage and the distinctive columnar porous structure of DE, which increased the exposure of α-Fe0 core for enhanced Cr(VI) reduction during their cotransport in the water-saturated soil system. X-ray absorption fine structure and X-ray photoelectron spectroscopy analyses confirmed that nZVI@GT/DE released more Fe(II) ions to reduce Cr(VI) to bidentate binuclear Cr(OH)3 (vs FeOCr2O3) complexes. This study unraveled the molecular mechanism and highlighted the Cr speciation transformation and physiochemical property changes of nZVI@GT/DE during their cotransporting when applied in situ remediation in complex subsurface of Cr(VI)-contaminated groundwater and soil system.
研究领域:
环境科学
·
材料科学
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Tianwen Zheng,Daibing Hou,Naijin Wu,Moxi Wang,Nan Luo,Huilong Luo,Wenpeng Leng,Peizhong Li,Wenxia Wei
Microbial induced calcium carbonate precipitation (MICP) is a green and environmentally friendly technology . Herein, porous biological CaCO 3 was prepared by MICP technology and then used as the carrier material for nZVI to prepare CaCO 3 @nZVI composite. Afterwards, the various properties of the CaCO 3 @nZVI composite were methodically characterized. Subsequently, the adsorption kinetic equation and adsorption isotherm model of TCE were carefully investigated, and the CaCO 3 @nZVI composite dosage, initial pH, temperature, aging time and the number of cycles on the TCE removal efficiency were examined. Finally, the degradation mechanism of TCE by CaCO 3 @nZVI composite was revealed. The results showed that nZVI particles were successfully supported on the biological CaCO 3 surface, and the specific surface area of the CaCO 3 @nZVI composite was 52.641 m 2 /g, which was much higher than that of bare nZVI (8.757 m 2 /g). The adsorption kinetics of CaCO 3 @nZVI composite for TCE removal was conformed to the pseudo-second-order kinetic equation, and Freundlich model was more appropriate as the adsorption isotherm model. The optimal conditions for the TCE removal were obtained to be 0.24 g/L CaCO 3 @nZVI composite dosage, 25 ℃, and initial pH of 7.0, respectively. Furthermore, the CaCO 3 @nZVI composite exhibited good stability and reusability. The main degradation products of TCE by CaCO 3 @nZVI composite were acetylene, ethylene, and ethane, and the synergistic effects of adsorption and degradation were the main mechanisms of TCE removal. Generally, this paper provides experimental support for the selection of nZVI carrier materials, which is useful for promoting the development and advancement of green repair materials.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
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IF 9.8
Daibing Hou,Xuedan Cui,Meng Liu,Hantong Qie,Yiming Tang,Wenpeng Leng,Nan Luo,Huilong Luo,Aijun Lin,Wenjie Yang,Wenxia Wei,Tianwen Zheng
Direct electron transfer and the involvement of atomic hydrogen (H ⁎ ) are considered the main mechanisms for reductive dechlorination promoted by nano zero-valent iron (nZVI) supported on highly conductive carbon. It is still unclear how precisely H ⁎ , the specific surface area, and the electrochemical characteristics contribute to biochar supported nano zero-valent iron (BC-nZVI) activity in chlorinated hydrocarbon contaminant removal. In this study, a range of BC-nZVIs were prepared by a liquid-phase reduction process, and the contributions of specific surface area and electrochemical performance to H ⁎ generation and electron transfer have been assessed. The mechanism of trichloroethylene (TCE) dechlorination by BC-nZVIs has been evaluated in terms of removal efficiency and the ultimate degradation products . The results have demonstrated that BC-nZVIs exhibit a higher specific surface area and TCE degradation efficiency compared with the bare nZVI. Ethane, ethylene, and acetylene were the principal TCE degradation products. The elimination of TCE was not significantly affected by differences in BC-nZVI specific surface area, but electron transfer and sustained generation of H ⁎ were dependent on the catalyst electrochemical characteristics. The electrochemical properties of biochar serve to lower the corrosion potential of nZVI, improving electronic transfer capability and reactivity and promoting direct electron transfer for the degradation of TCE. In addition, the enhanced electrochemical properties also facilitate the reaction of nZVI with water and can promote the sustained generation of H ⁎ . Generation of H ⁎ played a key role in reductive dechlorination over BC-nZVIs, which was related to the properties of the biochar support. This study focuses on the role of H ⁎ and electrochemical performance in TCE reductive dechlorination, and provides a theoretical foundation and experimental support for the practical application of BC-nZVIs.
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Journal of Material Cycles and Waste Management
·
2013
·Vol. 15
·期 4
·461-468
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IF 0.568
Su Lianghu,Shi Xinlong,Guo Guangzhai,Zhao Aihua,Zhao Youcai
The potential benefits of nanoscale zero-valent iron (nZVI) on sludge stabilization, either the abatement of odor or the improvement of biogas production, were investigated in this study. Two commercial-grade microscale iron powders were also utilized for comparison. Adding 0.10 wt% of nZVI in sludge during anaerobic incubation significantly reduced the concentration of H 2 S in biogas by 98.0 % (96.2–98.9 %), probably attributed by reactions between sulfides and the neo-formed hydrous Fe(II)/Fe(III) oxides layer at the surface of ZVI nanoparticles. Meanwhile, the percentage of P in bioavailable fractions decreased from 76.8 to 52.5 %, possibly due to the formation of vivianite [Fe 3 (PO 4 ) 2 ]. Furthermore, 0.10 wt% of nZVI in anaerobic digestion for 17 days enhanced the concentration of CH 4 in biogas by 5.1–13.2 % and improved the production of biogas and methane by 30.4 and 40.4 %, respectively. The amendment of iron nanoparticles during anaerobic digestion can not only effectively reduce H 2 S in biogas, but also potentially boost methane production significantly.
研究领域:
环境科学
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微生物学
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2016
·
IF 8.328
Lei Tan,Shaoyou Lu,Zhanqiang Fang,Wen Cheng,Eric Pokeung Tsang
The magnetic Fe 0 @Fe 3 O 4 nanocomposite was prepared and used to achieve the reductive/subsequent oxidative ring-opening of decabromodiphenyl ether (BDE209) in this work. The characterization results indicated that the structure of the composite consisted of small nanoscale zero-valent iron (nZVI) particles surrounding the surface of Fe 3 O 4 nanoparticle (NP). A 100% removal efficiency and 80% degradation efficiency of BDE209 was reached by the composite accompanied with ultrasound(called NP/US system) for 36 h, which is higher than that obtained with conventional nZVI particles. Furthermore, the enhanced debromination and ring-opening of BDE209 was realized by a Fenton-like degradation process lasting for 12 h after the addition of H 2 O 2 to the NP/US reaction at 36 h. Based on the degradation products identified, a two-stage reduction/oxidation degradation mechanism was proposed. During the first stage, which was reductive debromination, the major reductive activity of nZVI was efficiently enhanced in the presence of nano Fe 3 O 4 , which served as a catalyst to improve the stability of the nZVI nanoparticles and accelerate electron transfer, enhancing the degradation efficiency of BDE209. During the second stage, the oxidative ring-opening, the debromination products of BDE209 were proved to be attacked by abundant hydroxyl radicals generated both in the solution and on the surface of the Fe 0 @Fe 3 O 4 nanoparticles. Thus, this work provides an efficient method to achieve the complete ring-opening of PBDEs using iron-based nanomaterials.
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ENVIRONMENTAL RESEARCH
·
2020
·
IF 5.715
Yan Yi,Xiangyu Wang,Jun Ma,Ping Ning
Egeria najas is a submerged aquatic plant, and the literatures on resourcification of submerged aquatic plant biochar remain limited. Until now, there has been no study on submerged aquatic plant biochar supported nZVI that is widely applied for removal of diversified contaminants in solution. In this study, an efficient approach to the preparation of Egeria najas- derived biochar supported nZVI composite is first developed for Cr(VI) removal in wastewater. The adsorption behavior and mechanism of Cr(VI) removal on the as-prepared Egeria najas- derived biochar/nZVI (EN@nZVI) composite were investigated. The results of FTIR and XPS indicate that the EN@nZVI surface had many functional groups such as R-COOH, R-OH, R-NH 2 and R-C-O-C, etc, which could provide active sites during the adsorption process. The BET results showed that the EN@nZVI had large specific surface area and average pore, which were 142.49 m 2 /g and 9.85 nm, respectively. EN@nZVI demonstrated high reactivity for Cr(VI) removal. Compared with nZVI, Cr(VI) removal efficiency by EN@nZVI is 50% higher than that of nZVI within 0.5 h. Furthermore, the maximum adsorption capacity of Cr (VI) was 56.79 mg/g and the energy of activation (E a ) was 31.30 kJ/mol. The adsorption process was well described by the pseudo-second order model and Sips adsorption isotherm model. The reaction mechanism of Cr(VI) removal was a multi-step removal mechanism, involving adsorption, surface complex formation, reduction and ion exchange reaction.
研究领域:
环境科学
·
材料科学
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Energy Reports
·
2020
·
IF 3.595
Mingxing Zhao,Ziyi Liu,Jin Xu,He Liu,Xiaohu Dai,Sai Gu,Wenquan Ruan
The effect of nano zero valent iron (NZVI) on hydrogen production by the co-digestion of dry lake algae and food waste was investigated. The results showed that 10 mg.gTS −1 addition of NZVI improved the performance of the co-digestion system, with the cumulative hydrogen increased by 29.20% to 40.04 mL.gVS −1 , compared to that of the control. However, the cumulative hydrogen yield decreased to 14.77 and 5.37 mL.gVS −1 when the NZVI dosage was increased to 20 and 40 mg.gTS −1 , respectively. The oxidation reduction potential (ORP) of the reaction system was decreased dramatically to -331 ∼ -490 mV at the initial reaction stage. The degradation rates of carbohydrate and protein also reached their peaks at the NZVI dosage of 10 mg.gTS −1 . The concentration of end product in the liquid phase and the dehydrogenase activity was first increased then decreased when enhancing the NZVI dosage. Analysis of the transmission electron microscopy images revealed that excessive NZVI dosage could destroy the cells of microorganisms.
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Li Liang,Xiaoqin Li,Yiqing Guo,Zhang Lin,Xintai Su,Bo Liu
In this study, the reaction between sulfidated nanoscale zero-valent iron (S-nZVI) and heavy metal cations as well as the role of sulfur were investigated. The results showed the corrosion products of S-nZVI were lepidocrocite ( γ -FeOOH) or/and magnetite (Fe 3 O 4 ), depending on heavy metal species. While the removal of Hg(II), Ag(I), Cu(II), and Pb(II) by S-nZVI was rapid and could achieve over 99% within 5 mins, the removal of Ni(II) and Zn(II) was low in efficiency and unstable. Sulfur was existed as iron sulfides at fresh S-nZVI, but was displaced by the heavy metals and formed the related sulfide compound, or oxidized to S 0 and SO 4 2- . The removal mechanisms are strongly dependent on the solubility product constant (K sp ) of metal sulfides. For Hg(II) and Ag(I), with K sp of corresponding metal sulfides much lower than that of iron sulfide, the removal mechanism is the displacement reaction. For Cu(II) and Pb(II), with K sp of corresponding metal sulfides moderately lower than that of iron sulfide, the removal mechanisms are the displacement reaction and complexation with surface groups of S-nZVI. For Zn(II) and Ni(II), whose K sp of corresponding metal sulfides slightly lower than that of iron sulfide, are mainly removed by complexation with surface groups of S-nZVI.
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