ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Wenqiang Xu,Chenyun Xia,Feng He,Zhenyu Wang,Liyuan Liang
Sulfidation of nanoscale zerovalent iron (nZVI) can enhance particle performance. However, the underlying mechanisms of nZVI sulfidation are poorly known. We studied the effects of Fe2+ on 24-h dynamics of nZVI sulfidation by HS– using a dosed S to Fe molar ratio of 0.2. This shows that in the absence of Fe2+, HS– rapidly adsorbed onto nZVI particles and reacted with surface iron oxide to form mackinawite and greigite (<0.5 h). As nZVI corrosion progressed, amorphous FeSx in solution deposited on nZVI, forming S-nZVI (0.5–24 h). However, in the initial presence of Fe2+, the rapid reaction between HS– and Fe2+ produced amorphous FeSx, which deposited on the nZVI and corroded the surface iron oxide layer (<0.25 h). This was followed by redeposition of colloidal iron (hydr)oxide on the particle surface (0.25–8 h) and deposition of residual FeSx (8–24 h) on S-nZVI. S loading on S-nZVI was 1 order of magnitude higher when Fe2+ was present. Surface characterization of the sulfidated particles by TEM-SAED, XPS, and XAFS verified the solution dynamics and demonstrated that S2– and S22–/Sn2– were the principal reduced S species on S-nZVI. This study provides a methodology to tune sulfur loading and S speciation on S-nZVI to suit remediation needs.
研究领域:
环境科学
·
材料科学
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DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Yixin Huang,Jing Zou,Jiawen Li,Hongfang Ma,Siying Chen,Lingying Chen,Xiaobin Liao,Jun Ma
In this study, a rapid, sensitive and reliable spectrophotometric method for peroxydisulfate (PDS) determination in water was established. The proposed spectrophotometric method was based on the oxidation of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) to form stable and green-colored ABTS radical (ABTS • + ) by ferrous ion (Fe(II))-catalyzed PDS. The formed ABTS • + performed well linear relationship with PDS concentration (R 2 > 0.999) in the range of 0–60 μM at four wavelengths of 415, 650, 732, and 820 nm under optimized conditions. The proposed Fe(II)-ABTS spectrophotometric method was highly sensitive with the absorptivity of 3.595 × 10 4 M −1 cm −1 , 1.530 × 10 4 M −1 cm −1 , 1.945 × 10 4 M −1 cm −1 and 1.768 × 10 4 M −1 cm −1 at four detection peaks of 415, 650, 732 and 820 nm, respectively. Additionally, the proposed Fe(II)-ABTS spectrophotometric method possessed well anti-interference capacity to common natural water constituents and was reliable to determine PDS concentration in water. What’s more, the proposed Fe(II)-ABTS spectrophotometric method was successfully applied in monitoring the change of PDS concentration during the degradation of diclofenac in heat-activated PDS process. In a word, the proposed Fe(II)-ABTS spectrophotometric method could be employed as a promising approach for the rapid and accurate measurement of PDS in water, and this study provided a new perspective for the measurement of PDS by the visible spectrophotometry .
研究领域:
分析化学
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环境科学
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DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2024
·Vol. 50
·期 6
·2743-2761
·
IF 2.8
Lin Yingzi,Chen Jing,Chen Junjie,Chen Lei,Yang Hong,Sun ShengBo,Sun Ningning,Weng Qixuan,Tian Shiqi
To address the disadvantage of poor degradation effect of Fe 2+ /peroxydisulfate (PDS) system, a co-catalyst was introduced in this study to construct a molybdenum (Mo)/Fe 2+ /PDS system for the degradation of Acid Orange 7 (AO7), and the degradation rate could reach 95.67%. The effects of different parameters (initial pH, Fe 2+ concentration, etc.) on the degradation effect of AO7 in this system were investigated, and the optimal degradation conditions were obtained by combining cost analysis. Cycling experiments showed that Mo had good stability. The co-catalytic mechanism of Mo powder was determined using X-Ray Diffraction, Scanning Electron Microscope, and X-ray Photoelectron Spectroscopy. The effects of different inorganic anions on AO7 were discussed: Cl − and NO 3 − had little effect on degradation, while SO 4 2− and HCO 3 − both inhibited the removal of AO7 from the system to different degrees, with HCO 3 − showing a greater inhibition than SO 4 2− . The main active radicals were identified as sulfate radical (SO 4 ·− ) and hydroxyl radical (·OH). In addition, intermediates were identified, and the attack sites were determined by combining the highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels and the Fukui index to hypothesize the degradation pathways. Toxicity indicators such as the mutagenicity of AO7 and intermediates were evaluated, and the overall trend of toxicity was decreasing. This study is expected to provide an efficient treatment process for dye wastewater.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
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IF 9.038
Guangda Yu,Fenglian Fu,Chujia Ye,Bing Tang
The mobility of Cr(VI) in the environment is affected by the transformation of ferrihydrite (Fh) and ferrihydrite-humic acid co-precipitates (Fh-HA). However, the impacts of Fe(II)-induced transformation of Fh and Fh-HA on the mobility, speciation and partitioning of associated Cr(VI) remain unclear. In this study, the behaviors of adsorbed Cr(VI) during Fh and Fh-HA aging at 70 °C for 9 days (pH 0 = 3.0 and 7.0) in the absence and presence of Fe(II) were studied. Results revealed that the main speciation of Cr(VI) after transformation was non-desorbable Cr and its formation involved the following pathways. Firstly, Fe(II) (0.2 and 2.0 mM) induced the transformation of Fh-HA to hematite and goethite, promoting the structural incorporation of adsorbed Cr into hematite and goethite via complexation. Secondly, under neutral condition (pH 0 = 7.0), the low concentration of Fe(II) (0.2 mM) could not reduce completely Cr(VI) to Cr(III) and thus residual Cr(VI) was incorporated into the Cr(III)-Fe(III) co-precipitates. Thirdly, coprecipitated humic acid not only reduced Cr(VI) to Cr(III) via polysaccharide, but also formed complexes with incorporated Cr through carboxylic groups to sequester Cr. Our results demonstrate that Fe(II)-induced transformation of Fh-HA exerts major influences on associated Cr(VI) speciation and partitioning.
研究领域:
环境科学
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化学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Xiaobing Wang,Yueyao Wang,Na Chen,Yanbiao Shi,Lizhi Zhang
Persulfate (PS) is widely used for environmental remediation, but its organic contaminant removal performance strongly depends on its activation. In this study, we demonstrate that pyrite (FeS 2 ) can more effectively activate PS than the commonly used FeSO 4 for atrazine degradation. When 3.0 mM of PS and 4.2 mM of iron salts were used, the atrazine degradation efficiency of FeS 2 /PS was 1.4 times that of FeSO 4 /PS, while the amount of consumed PS in case of FeS 2 was only 53% of that by FeSO 4 . The better PS activation performance of FeS 2 could be attributed to its slow and sustainable release of dissolved Fe(II), inhibiting the quenching reaction between •SO 4 − /•OH and Fe(II) ions, and thus producing more reactive oxygen species for the atrazine degradation. More importantly, the surface bound Fe(II) of FeS 2 could activate molecular oxygen to generate superoxide radical (•O 2 − ), which could further promote the effective decomposition of PS by accelerating the Fe(III)/Fe(II) redox cycle. This study unravels the roles of dissolved Fe(II) and surface bound Fe(II) on the persulfate activation, and provides a promising heterogeneous persulfate activator for pollutant control and environmental remediation.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Chunsheng Ding,Xinze Song,Zhongyi Zheng,Hainan Wang,Yuqiang Pan,Hangtian Zhang,Xueyan Li,Jing Deng
Fe(II)-catalyzed PMS process was widely used in the degradation of refractory pollutants in wastewater, while its performance was restricted by the slow regeneration efficiency of Fe(II). Herein, caffeic acid (CFA), a representative of hydroxycinnamic acids, was introduced into Fe(III)/PMS system to accelerate the transformation of Fe(III) to Fe(II) and promote the removal of bisphenol A (BPA). Under optimum condition of 0.1 mM CFA, 0.05 mM Fe(III), and 0.5 mM PMS, almost complete removal of BPA can be achieved within 20 min, which was roughly 6.2 times higher than that in Fe(III)/PMS system. As the addition of CFA into Fe(III)/PMS system, pH application range was widened from acidic to alkaline conditions. The reduction and chelation of CFA expedited the Fe(III)/Fe(II) cycle by forming CFA-Fe chelate, thereby facilitating the PMS activation . Based on LC-MS analysis and DFT calculation, the intermediate products of CFA were found to play a decisive role in boosting the regeneration of Fe(II), and the toxicity of these intermediates towards organisms was evaluated by ECOSAR . The alcohol-scavenging and chemical probe tests certified that hydroxyl radical (•OH), sulfate radical (SO 4 •- ), and Fe(IV) coexisted in Fe(III)/CFA/PMS system, and the second-order reaction rate constants of •OH and SO 4 •- reacted with CFA were calculated to be 3.16✕10 9 and 2.30✕10 10 M −1 s −1 , respectively. Two major degradation pathways of BPA, •OH addition and SO 4 •- induced hydroxylation reaction, were proposed. This work presented a novel green phenolic compound that expedited the Fe(II)-catalyzed PMS activation process for the treatment of organic contaminants .
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Foods
·
2025
·Vol. 14
·期 7
·1097
·
IF 5.1
Jin Lu,Zhilei Zhou,Mengyang Huang,Zhongwei Ji,Hui Qin,Jian Mao
This research examined the influences of electric field strength and pulse frequency of pulsed electric field (PEF) treatment, along with the combined effects of dissolved oxygen and ferrous iron ions on the aroma and components of strong-flavor baijiu. PEF treatment improved fruity aromas and decreased the pit mud odor. Electric field strength promoted the production of short-chain fatty acid esters, while pulse frequency facilitated the formation of acetal oxidation products. The most notable changes were observed at an electric field strength of 25 kV, and a pulse frequency of 350 Hz. Increasing dissolved oxygen significantly improves fruity and mellow aromas and promotes the generation of 17 compounds including ethyl lactate, ethyl butyrate, hexan-1-ol, octanoic acid, and 3-methylbutanal, while Fe 2 ⁺ treatment reduces the fruity aroma of baijiu and significantly suppresses the production of 15 esters including ethyl hexanoate, hexyl hexanoate, and ethyl lactate. Dissolved oxygen may contribute to the generation of hydroxyl radicals and regulated oxidation reactions partially in baijiu. And, Fe 2+ may react with organic acids to promote the hydrolysis of ester compounds. This study aims to offer valuable insights into the practical application of PEF in the flavor regulation of baijiu.
研究领域:
食品科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Jing-Ping Zhu,Yi-Li Lin,Tian-Yang Zhang,Tong-Cheng Cao,Bin Xu,Yang Pan,Xi-Tong Zhang,Nai-Yun Gao
Iohexol can hardly be removed in conventional wastewater treatment processes due to its non-biodegradable and hydrophilic characteristics. In this study, a kinetic model was established to describe iohexol degradation in Fe (II)-activated persulfate system. The developed model can well predict iohexol degradation and evolution of sulfate radical with various initial iohexol and oxidant (ferrous iron and persulfate) concentrations under various water matrix. The rate constant of iohexol reacting with sulfate radical was calculated as (1.83 ± 0.10) × 10 9 M −1 s −1 . The effects of the two most common components in natural water bodies, chloride ion and natural organic matter (NOM) on iohexol degradation, were also studied. Both experimental data and model results showed that the low concentration of chloride ion promoted iohexol degradation while high concentration inhibited it, and NOM slightly inhibited iohexol degradation. Besides, radical quenching tests were employed to identify the main radicals formed in the system and further verified the model accuracy. The model is also capable of predicting the atrazine degradation with the correlation coefficients between the experimental data and predicted results above 0.97, suggesting the applicability of the established model for some other recalcitrant contaminant degradation in the Fe 2+ /PS system.
研究领域:
环境科学
·
化学工程
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DOI
高影响因子
WATER RESEARCH
·
2017
·
IF 6.942
Xiaoxiang Cheng,Heng Liang,An Ding,Xiaobin Tang,Bin Liu,Xuewu Zhu,Zhendong Gan,Daoji Wu,Guibai Li
Ferrous iron/peroxymonosulfate (Fe(II)/PMS) oxidation was employed as a pretreatment method for ultrafiltration process to control membrane fouling caused by natural organic matter, including humic acid (HA), sodium alginate (SA), bovine serum albumin (BSA), and their mixture (HA-SA-BSA). To evaluate the mechanism of fouling mitigation, the effects of Fe(II)/PMS pretreatment on the characteristics of feed water were examined. The degradation of atrazine (ATZ) was also investigated and the species of generated radicals were preliminarily determined. Under the test exposure (15 and 50 μM), Fe(II)/PMS pretreatment effectively mitigated membrane fouling caused by HA, SA and HA-SA-BSA mixture, and the performance improved with the increase of Fe(II) or PMS dose; whereas aggravated BSA fouling at lower doses and fouling alleviation was observed only at a higher dose (50/50 μΜ). The fouling mitigation was mainly attributed to the effective reduction of organic loadings by coagulation with in-situ formed Fe(III). Its performance was comparable or even slightly higher than single coagulation with Fe(III), most likely due to the oxidation by Fe(II)/PMS process. Fe(II)/PMS oxidation showed better performance in reducing DOC and UV 254 , fluorescence intensities of fluorescent components and UV-absorbing compounds than single coagulation. In addition, Fe(II)/PMS pretreatment was efficient in ATZ degradation due to the generation of sulfate and hydroxyl radicals , whereas coagulation was ineffective to remove it.
研究领域:
环境科学
·
水处理技术
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Fuwei Sun,Haibo Liu,Hanlin Wang,Daobing Shu,Tianhu Chen,Xuehua Zou,Fangju Huang,Dong Chen
Natural iron-bearing minerals have been proven to be effective for activating H 2 O 2 to produce OH, which can be used to degrade organic pollutants . In this study, the performance of siderite to degrade sodium sulfadiazine via catalytic H 2 O 2 degradation was investigated at different solution pH values from 3 to 9. An interesting discovery was made: the performance of the siderite-H 2 O 2 system was excellent under acidic, neutral, and even alkaline conditions. The influence of various factors (e.g. initial concentration, anions, natural organic matters, etc.) on the system under different pH conditions was investigated, which confirmed that siderite exhibited an excellent catalytic performance. By combining EPR characterization with scavenger research, it was proposed that dissolved iron (Fe 2+ ) mainly initiated the homogenous Fenton reaction to degrade pollutants under acidic conditions, while structural Fe 2+ species present in siderite triggered Fenton-like reactions under neutral or even alkaline conditions. From the SEM and XPS characterizations, oxidation and dissolution of Fe 2+ on the surface were also observed, confirming our inference concerning the different reaction mechanisms. The experimental findings show that this siderite-H 2 O 2 system can be used in solutions with pH values from 3 to 9 and that siderite plays a positive role in soil and groundwater remediation when H 2 O 2 is used as an oxidant.
研究领域:
环境科学
·
化学
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DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Xiaoyan Chen,Wei Miao,Yulin Yang,Sibei Hao,Shun Mao
In this study, an Fe(Ⅱ)/S(IV) system was designed for the degradation of chloramphenicol (CAP). The pseudo-first-order rate constants for CAP degradation under typical conditions with and without air purging were investigated. The greatly enhanced rate of 0.0099 min −1 with air purging compared with 0.0006 min −1 with no air purging indicated that aeration was significant to the degradation of CAP in Fe(Ⅱ)/S(Ⅳ) system. Radical scavenging experiments revealed that SO 4 - was the primary oxidant generated from the activation of S(IV) with Fe(II), accounting for around 70% of degradation under weak acidic and neutral conditions. Increasing Fe(II) and S(IV) doses promoted the degradation of CAP, whereas the overdose of them led to a decreased degradation rate by scavenging radicals. Owing to the participation of oxygen in the formation of ferric sulfite complex and SO 5 - , the increase of dissolved oxygen improved the removal efficiency of CAP. The removal efficiency of CAP was also found to be pH dependent, decreasing from acid condition (initial pH = 4) to basic condition (initial pH = 8). The presence of coexisting anions and water matrix was found inhibiting CAP degradation in Fe(Ⅱ)/S(Ⅳ) system. This work provides an understanding on the working mechanism and possible applications of Fe(Ⅱ)/S(Ⅳ) system in organic compound degradation in wastewater.
研究领域:
环境科学
·
废水处理
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产品关联
DOI
PubMed
高影响因子
Minerals
·
2023
·Vol. 13
·期 2
·200
·
IF 2.5
Haiping Zhao,Xiaopeng Niu,Bingxu Dong,Xianbing Jia,Renman Ruan
The major problem with Carlin-type gold deposit flotation is that the high dolomite content in the concentrate decreases the quality of gold. Further, the activation mechanisms involved in dolomite flotation are still not fully understood. Herein, the correlation of Fe2+conversion with xanthate adsorption and dolomite flotation was investigated to reveal the effect of dolomite embedded with pyrite. Flotation tests suggested that Fe2+rather than Fe3+improved the floatability of dolomite from 20% to 45%. Contact angles and thermodynamic tests indicated that the hydrophobicity of Fe2+-modified dolomite corresponds to the adsorption of xanthate. Importantly, time-of-flight secondary ion mass spectroscopy (Tof-SIMS) and x-ray photoelectron spectroscopy (XPS) attributed the activation of dolomite flotation to the formation of Fe(OH)2and FeCO3. The coordination model of flotation successfully elucidated the selective adsorption of xanthate between Fe(OH)2, FeCO3and FeOOH surfaces. The density function theory (DFT) simulation calculation was performed to identify the reaction rate at the atomic level, and the density of states (DOS) was also conducted to verify the conclusions at the electronic level. This study presents important surface chemistry evidence for understanding and regulating the poor selectivity in the flotation of Carlin-type gold deposits.Keywords:ferrous hydroxide/carbonate;dolomite activation;coordination model;carlin-type gold deposits;flotation
研究领域:
矿物加工工程
·
表面化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）