CHEMOSPHERE
·
2020
·
IF 5.778
Meimei Du,Yongqing Zhang,Xianlin Zeng,Hainan Kuang,Shaobin Huang
In this study, the effect of ball milling on pyrite (FeS 2 ) promoting arsenic (As) removal by zero-valent iron (Fe 0 ) was investigated. The influences of different mass ratios of ball-milled FeS 2 /Fe 0 , the dosage of ball-milled FeS 2 /Fe 0 used and initial pH value were evaluated by batch experiments. The results showed that the ball-milled FeS 2 /Fe 0 system had a higher total As removal efficiency than the mixed FeS 2 –Fe 0 system, ball-milled FeS 2 and ball-milled Fe 0 systems in equal mass. Higher As removal efficiency in ball-milled FeS 2 /Fe 0 system was primarily related to the accelerated corrosion of Fe 0 , which was supported by the determination of total Fe 2+ release and electrochemical experiments. SEM-EDS and XPS characterizations revealed that there were iron sulfides (Fe(II)–S and Fe(III)–S) produced on the surface of Fe 0 in ball-milled FeS 2 /Fe 0 , which could facilitate the electron transfer of Fe 0 and enhanced the corrosion of it. BET test also indicated that ball-milled FeS 2 /Fe 0 possessed a higher specific surface area than ball-milled Fe 0 . In addition, the results also showed the optimum mass ratio of FeS 2 and Fe 0 in ball-milled FeS 2 /Fe 0 to remove As ([As(III)] = 2 mg/L) was 1:1, and the optimum dosage was 0.5 g/L, thereby indicating the optimal As:Fe 0 molar ratio was about 1:168. And the removal rate of As by ball-milled FeS 2 /Fe 0 was faster in acidic condition than that in alkaline condition. These findings suggest that Fe 0 -based arsenic removal efficiency can be enhanced by ball-milling with FeS 2 , making it more feasible for remediation of arsenic-polluted water.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yanchao Qiao,Huimin Wang,Chao Liu,Shuang Luo
Laterite nickel ore is rich in nickel and iron resources, and the nickel element is extracted in the form of nickel salt. However, the acid-leaching tailings of laterite nickel ore (LTLNO), which contain valuable iron resources, have not been cost-effectively recovered. In this work, we designed a novel method to extract iron from LTLNO and recycle it into high-valuable iron phosphate products using only phosphoric acid and iron powder. We explored the effects of reaction parameters, such as phosphoric acid concentration, iron powder dosage, time, and temperature, on the leaching behavior of key elements. The results showed that the iron leaching rate was as high as 96.54 % when using 3.5 mol/L phosphoric acid with a liquid-to-solid ratio (L/S) of 5 mL/g and an iron powder dosage based on the Fe/Fe n+ ratio of 0.5 after 3 h at 25 °C, and a final high-purity FePO 4 (99.4 %) was obtained. Kinetic analysis revealed that the leaching reaction was controlled by the diffusion through the neogenetic layer, and the leaching reactions were thermodynamically favorable. This method allows for a simpler and more efficient recovery of iron and the products of higher-value iron phosphate products than other LTLNO recycling technologies. Additionally, it offers a total economic benefit of $134/t for LTLNO treatment, demonstrating great prospects for industrial application.
研究领域:
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2023
·
IF 2.8
Yi Li,Naijin Wu,Jiuhao Song,Zhenxia Wang,Peizhong Li,Yun Song
The in-situ reduction of zero-valent iron (ZVI) is an effective method for removing chlorinated aliphatic hydrocarbons (CAHs) from groundwater. The heterogeneity of environmental conditions is also crucial in affecting dechlorination efficiency. Until now, the effect of Sulfate (SO42–) on ZVI activity has been debated, and the related mechanism research on SO42– behaviour during the abiotic reduction process of chlorinated alkanes is still lacking. In this study, the impacts of SO42– concentrations (0, 2, 4, 8, 80 mM) on the degradation of 1,1,2-trichloroethane (1,1,2-TCA) by micron-size ZVI (mZVI) and nano-size ZVI (nZVI) were systematically investigated. For mZVI, Kobs increased by 0.6 (2 mM), 0.5 (4 mM), 1.1 (8 mM), and 1.6 times (80 mM). For nZVI, Kobs decreased by 32% (2 mM), 39% (4 mM), 45% (8 mM), and 9% (80 mM). The results showed that SO42– increased the rate of 1,1,2-TCA degradation by mZVI but weakened the reduction performance of nZVI; however, this inhibition was reduced when the concentration reached 80 mM. SO42− controlled the degradation of 1,1,2-TCA mainly through the formation of different iron-sulfate complexes on the ZVI surface: water-soluble bidentate iron-sulfate complexes formed on the mZVI surface promoted the corrosion of the oxide layer and accelerated the reduction of 1,1,2-TCA, monodentate complexes mainly formed on the nZVI surface inhibited the reduction of 1,1,2-TCA by blocking surface sites. These results demonstrate the proof of concept to assist land managers in the field application of ZVI technology for the remediation of CAHs contaminated sites with different background concentrations of SO42−.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Silan Zhao,Lifang Gong,Guangzhao Guo,Huimin Liu,Shuai Li,Lu Dong,Shuang Deng,Hongyun Hu
A large number of fly ash samples from mechanical grate furnaces at a municipal solid waste incineration (MSWI) plant were examined including Se speciation and content. Se leaching behaviors before and after solidification/stabilization(S/S) treatment were comparatively studied. The results showed that Se in the MSWI fly ash was present mainly in the form of selenite with small amounts of physically adsorbed SeO 2 (s). Se in the low alkalinity ash (pH ∼ 7) tended to be more leachable than that in the high alkalinity ash (pH ∼ 12). The chelation treatment would further raise the risk of Se leaching into the environment from the low alkalinity ash (pH ∼ 7). Three Fe-containing additives (zero-valent iron (ZVI)、α-Fe 2 O 3 and Fe 3 O 4 ) were introduced, respectively in attempt to immobilize Se in the low alkalinity MSWI fly ash. A strong positive effect was found with ZVI addition in terms of Se leaching from low alkalinity chelated MSWI ash. Comparatively, iron oxides showed no obvious effect. The adjustment to ash alkalinity (CaO addition) exhibited a comparable effect to ZVI addition, which provided another option to control Se leaching from low alkalinity chelated ash.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2025
·
IF 11.3
Shichao Cai,Jiawei Zhao,Yurou Tan,Zhongkuan Wu,Bo Chen,Feng He
In this study, we synthesized microscale sulfidated zerovalent iron (S-mZVI) with controllable mackinawite (FeS) content up to nearly 100 wt % and investigated the roles of FeS and Fe0 for arsenite (As(III)) sequestration under aerobic conditions. Batch experiments show that FeS and Fe0 contents determine the kinetics and longevity of As removal by S-mZVI, respectively. The Fe0/FeS galvanic cell accelerates the consumption of Fe0 by dissolved oxygen (DO) while preserving FeS to preferentially remove As as sulfide, which is protected from oxidation by Fe0. In column studies, mZVI and S0 were mixed in sand to form S-mZVI in situ. Results of sequential extraction of reacted S-mZVI particles from different column zones and run stages further indicate that As formed as sulfide by S-mZVI, which was then oxidized by DO after Fe0 depletion to form As-iron (hydr)oxides. X-ray absorption near-edge structure characterization confirmed that As sulfide is mainly in the form of realgar (As4S4). S-mZVI (2 wt % of column sand) reduces total As from 2 mg/L to 10 μg/L, up to 300 bed volumes, with a residence time of 70 min. In situ synthesis and cost advantages make S-mZVI a promising method to address As contamination issues worldwide.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2024
·
IF 4.5
Huiping Zeng,Xiao Sun,Siqi Sun,Weihua Zhao,Ruixia Hao,Jie Zhang,Dong Li
Combining natural polymer starch with magnetite nanoparticles (MNPs) can reduce the aggregation of MNPs and enhance their adsorption capacity and stability. Iron sludge from a de‑ironing water plant and starch were employed as basic ingredients in this study. Bare magnetite nanoparticles (MNPs) and starch-coated magnetite nanocomposites (ST 2 -MNPs) were synthesized by a “green” co-precipitation method for the removal of low-concentration As(V) solutions. TEM, XPS, FTIR, XRD, VSM, BET, and TGA techniques were used to examine the physicochemical properties of the synthesized ST 2 -MNPs. TEM verified that the magnetite nanoparticles in the composites were evenly distributed. The ST 2 -MNPs (5.26 nm) possessed a smaller average particle size than MNPs (6.24 nm). And VSM confirmed their remarkable magnetic properties. The starch-to‑iron-sludge ratio was optimized and the influence of adsorbent dosage, pH, and co-existing anions on As(V) adsorption were studied. The acquired arsenate adsorption data were found to be consistent with the Langmuir isotherm model, with maximum adsorption capacities of 23.04 mg/g for MNPs and 42.88 mg/g for ST 2 -MNPs. This shows that the active sites on MNPs and ST 2 -MNPs are energetically homogenous, and that the addition of starch coating significantly increases magnetite's adsorption capacity for As(V). The adsorption kinetics follow a Pseudo-second-order kinetic model, indicating chemisorption between As(V) and ST 2 -MNPs. In addition, the adsorption mechanism of As(V) by ST 2 -MNPs including chemical adsorption and electrostatic attraction was determined through in-depth discussion of characterization methods and adsorption experiments. This study offers references for the removal of As(V) and the resourceful application of backwash iron sludge.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Meimei Du,Yongqing Zhang,Imtyaz Hussain,Xiaodong Du,Shaobin Huang,William Wen
In this study, the enhanced effect of pyrite (FeS 2 ) on zero-valent iron (Fe 0 ) corrosion for arsenic (As) removal was investigated in a combined-Fe 0 /FeS 2 system. The effects of different Fe 0 /FeS 2 composition, dosage and initial pH were evaluated by batch experiments. Results showed that the best combination ratio of Fe 0 :FeS 2 (w/w) was 1:1 and the optimal dosage of mixture was 2.0 g/L. The combination of Fe 0 and FeS 2 in a system significantly enhanced the reactivity of Fe 0 for effective As removal within a broad pH range (3.0–9.0). The effective As removal in the combined-Fe 0 /FeS 2 system was primarily ascribed to being enhanced corrosion of Fe 0 by addition of FeS 2 . SEM and XRD characterizations strongly verified this point. Specifically, the mechanism study (the releases of Fe 2+ and total Fe ion, variations of pH values as well as XPS characterization) suggested that FeS 2 in the combined-Fe 0 /FeS 2 system could alleviate the passivation of Fe 0 (pH ini 3.0–5.0) and accelerate the dissolution of pristine oxide film that coated on Fe 0 surface (pH ini 6.8–9.0). Besides, FeS 2 in combined-Fe 0 /FeS 2 system could also accelerate the reactions between Fe 0 to O 2 at pH ini 3.0–9.0. These phenomena were well explained by a galvanic couple between Fe 0 and FeS 2 , where FeS 2 was a cathode and Fe 0 was an anode. Consequently, electrons released from Fe 0 that mediated by FeS 2 to oxide film, passivation layer and O 2 were accelerated in combined-Fe 0 /FeS 2 system and thereby enhanced the corrosion of Fe 0 for efficient As removal. Our findings suggest that utilizing FeS 2 to enhance the corrosion of Fe 0 would be a promising technology for remediation of As-contaminated water.
研究领域:
环境科学
·
水处理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Ying Lü,Jianfa Li,Yimin Li,Liping Liang,Huaping Dong,Kun Chen,Chunxia Yao,Zhanfeng Li,Jinxiang Li,Xiaohong Guan
Zero-valent iron (ZVI) is a popular reductant that has been successfully applied for remediation of groundwater contaminated with various pollutants, but it still suffers from surface passivation and pH increase in the reaction media. In this study, pyrite, a ubiquitous sulfide mineral in anaerobic environment, was adopted to enhance the reactivity of ZVI for removal of nitrobenzene. The synergetic effect between pyrite and ZVI was observed for nitrobenzene reduction, and the rate constant k obs at the initial pH (pH 0 ) 6.0 was enhanced by 8.55–23.1 folds due to the presence of pyrite with pyrite/ZVI mass ratio ranging from 1.0 to 6.0. Moreover, nitrobenzene could be removed effectively at pH 0 ranging from 5.0 to 10.0 in the presence of pyrite, while negligible removal of nitrobenzene by ZVI (0.5 g/L) alone was observed at pH 0 ≥7.0. ZVI sample recovered from the reacted ZVI/pyrite mixture was also more effective for nitrobenzene degradation than pristine ZVI. The mechanism study revealed that pyrite could suppress the pH increase in reaction media, boost the production of reactive Fe 2+ , and activate the ZVI surface through replacing partially the passive oxide film with iron sulfide (FeS). In particular, the formation of highly reactive FeS@Fe in the reaction system of ZVI/pyrite mixture was proved by XRD, Mössbauer, XANES, XPS and SEM-EDS analyses, which provides a facile way for in-situ sulfidation of ZVI and for enhancing the removal of contaminants with ZVI technology.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ying Lv,Linting Han,Jie Shen,Jianfa Li,Huaping Dong,Jiangang Hu,Yuxin He,Yimin Li
Chloramphenicol (CAP) is an effective bacteriostatic pharmaceutical that has been widely applied in clinical prescriptions, animal husbandry and aquaculture, but the residues excreted by human and animals have resulted in environmental pollution. Here, we investigated the mechanism of enhanced removal of CAP by zero-valent iron (ZVI) and pyrite mixture, the effect of environmental factors (i.e., initial pH, and co-solutes (anions, cations and organic matter)) as well as the potential applications and environmental safety of ZVI/pyrite mixture. Results show that the mixing of pyrite with ZVI enhanced the removal efficiency of CAP from 14.2% to 80–100% with a range of pyrite/ZVI mass ratios from 1.0 to 4.0. The environmental factors can change the surface reactivity and composition of pyrite/ZVI mixture, consequently altering the removal of CAP. Mechanism study revealed that pyrite could suppress the pH increase, mitigate the passivation of ZVI surface, and accelerate the production of reactive Fe(II). The X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization results of the solids after reacting at different pH conditions indicated formation of highly reactive secondary minerals (such as green rust and iron sulfide (FeS)). In addition, in different co-solutes systems, the secondary minerals are differed, leading to the change of ZVI surface reactivity. This study extends the knowledge of the effect of environmental condition on ZVI technology in practical engineering systems.
研究领域:
环境科学
·
污染治理
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Weiting Chen,Bing Li,Weizhao Yin,Weilong Zeng,Ping Li,Jinhua Wu
Zero-valent iron (ZVI), as an effective medium, is widely used to eliminate heavy metal ions in filter tanks. However, it will react with Cr(VI) to generate Fe–Cr precipitates with low conductivity on its surface, resulting in slow iron corrosion and low Cr(VI) removal efficiency. In this study, three oxidants (KMnO 4 , NaClO, and Na 2 S 2 O 8 ) were employed to promote iron corrosion in ZVI systems for enhanced Cr(VI) removal at a concentration of 5 mg/L through batch tests and column experiments. The ZVI/KMnO 4 , ZVI/NaClO, and ZVI/Na 2 S 2 O 8 systems achieved significantly higher Cr(VI) removal rates of 31.5%, 52.8%, and 65.9% than the ZVI system (9.8%). Solid phase characterization confirmed that these improvements were attributed to promoted iron corrosion and secondary mineral formation (e.g., lepidocrocite, ferrihydrite, and magnetite) by oxidants. Those minerals offered more reaction sites for Cr(VI) reduction, adsorption, and sequestration. Cycle experiments indicated that ZVI/oxidant systems could stably remove Cr(VI). In long-term column experiment, the ZVI/NaClO column showed a much longer life-span and exhibited a 34.8 times higher Cr(VI) removal capacity than that of the ZVI column. These findings demonstrated that ZVI in combination with a reasonable amount of oxidants was a promising method for removing Cr(VI) in practical filter tanks and provided a new insight to enhance Cr(VI) removal.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Jun Wan,Xiaoqing Jiang,Tian C. Zhang,Jiong Hu,Dana Richter-Egger,Xiaonan Feng,Aijiao Zhou,Tao Tao
Finding a good sorbent for phosphorus (P) recovery from the aquatic environment is critical for preventing eutrophication and providing P resources. The activated iron system (mainly consisted of zero-valent iron (ZVI), Fe 3 O 4 and Fe 2+ ) has been reported to exhibit a favorable performance towards various contaminants in wastewater, but its effect on P recovery has not been studied systematically. In this study, we used Fe 2+ -nitrate pretreatment reaction to prepare the activated iron system and then applied it to P recovery. Results show that more than 99% P was removed from water in 60 min; co-existing anions (NO 3 − , Cl − and SO 4 2− ) and natural organic matter (NOM) had little effect on P removal. The P removal capacity of activated iron system is very high compared with currently reported sorbents. Externally-supplied Fe 2+ plays an important role on P removal in the system. Regeneration study shows that the activated iron system exhibited stable P recovery ability by using 0.1 M NaOH solution. Various methods were applied to characterize the ZVI and iron corrosion, and results conclude that sorption precipitation, and co-precipitation contribute to P removal. This method will be promising and have an application potential in the field for efficient and cost-effective recovery of P with cheap microscale zero valent iron.
研究领域:
环境科学
·
水资源管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Meimei Du,Hainan Kuang,Yongqing Zhang,Xianlin Zeng,Conghao Yi,Imtyaz Hussain,Shaobin Huang,Shuaifei Zhao
Imidacloprid (IMI) removal by persulfate (PS) oxidation activated by ball-milled FeS 2 /Fe0 composite was investigated in terms of reaction conditions and mechanisms. The ball-milled FeS 2 /Fe 0 with a mass ratio of 1:9 exhibited the highest activating efficiency for PS among the investigated mass ratios of 9:1, 4:1, 1:1, 1:4 and 1:9. Increasing dosages of ball-milled FeS 2 /Fe 0 and PS promoted IMI removal. At initial pH of 4.6 and initial IMI concentration of 0.15 mol/L, the optimal dosage of ball-milled FeS 2 /Fe 0 and PS were 0.1 g/L and 2.5 mmol/L, respectively, removing 99.8% of IMI after 60-min reaction. The ball-milled FeS 2 /Fe 0 could also activate PS effectively in a wide pH range from 3 to 9. Characterizations including Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) revealed that the high activation efficiency was related to FeS produced on Fe 0 surface. Activation efficiency of PS was enhanced by accelerated electron transfer mediated by increased ferrous species, ultimately, the removal efficiency of IMI was improved. The released Fe 2+ activated PS to generate SO 4 -· and·OH. SO 4 -· was detected to be predominant reactive oxygen species in IMI degradation and three different pathways for IMI degradation were proposed. This study developed a efficient method to activate PS by FeS 2 modify Fe 0 prepared by ball milling a mixture of Fe 0 and FeS 2 , which can provide some new insights into the degradation of organic pollutants .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）