ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Zhen Cao,Hao Li,Gregory V. Lowry,Xiaoyang Shi,Xiangcheng Pan,Xinhua Xu,Graeme Henkelman,Jiang Xu
Groundwater contamination by halogenated organic compounds, especially fluorinated ones, threatens freshwater sources globally. Sulfidized nanoscale zero-valent iron (SNZVI), which is demonstrably effective for dechlorination of groundwater contaminants, has not been well explored for defluorination. Here, we show that SNZVI nanoparticles synthesized via a modified post-sulfidation method provide rapid dechlorination (∼1100 μmol m–2 day–1) and relatively fast defluorination (∼6 μmol m–2 day–1) of a halogenated emerging contaminant (florfenicol) under ambient conditions, the fastest rates that have ever been reported for Fe0-based technologies. Batch reactivity experiments, material characterizations, and theoretical calculations indicate that coating S onto the metallic Fe surface provides a highly chemically reactive surface and changes the primary dechlorination pathway from atomic H for nanoscale zero-valent iron (NZVI) to electron transfer for SNZVI. S and Fe sites are responsible for the direct electron transfer and atomic H-mediated reaction, respectively, and β-elimination is the primary defluorination pathway. Notably, the Cl atoms in florfenicol make the surface more chemically reactive for defluorination, either by increasing florfenicol adsorption or by electronic effects. The defluorination rate by SNZVI is ∼132–222 times higher with chlorine attached compared to the absence of chlorine in the molecule. These mechanistic insights could lead to new SNZVI materials for in situ groundwater remediation of fluorinated contaminants.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Yixin Pan,Yanbin Cai,Lujia Chen,Leilei Sun,Liping Deng,Rui Huang
In this study, nanoscale zero-valent iron was successfully soldered onto graphene oxide to synthesize nZVI/rGO nanocomposite by an improved modified Hummers' method. The nZVI/rGO nanocomposite was used to remove Re(VII) in water remediation , which was utilized as a replacement for the radioactive element of Technetium-99 (99Tc). The results showed that nZVI/rGO could effectively remove Re(VII) at pH = 13 with a removal efficiency of 99.1 %. rGO can effectively inhibit the aggregation of nZVI and significantly improve the removal performance. The removal capacity of nZVI minus the removal capacity of rGO in the composite was as high as 468.8 and 474.9 mg/g, respectively, corresponding to the mass ratio of Fe 0 :rGO = 1:1 and 1:2. However, the removal capacity of pure nZVI was only 33.5 mg/g, and that of the pure rGO was 42.6 mg/g. The removal capacity of Re(VII) by nZVI/rGO was not affected by cations of Na + , Ca 2+ , K + , and Mg 2+ ions. The removal efficiency of Fe 0 :rGO with a mass ratio of 1:1 and 1:2 was still higher than 60 % (63.5 % and 67.1 %, respectively). The results of this study demonstrate that the graphene oxide-based zerovalent iron nanocomposite under an appropriate mass ratio, can economically and efficiently remediate rhenium heavy metal ions in high pH water environments.
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
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Peiling Han,Jiayin Xie,Xueming Qin,Xinru Yang,Yongsheng Zhao
Micron zero valent iron (mZVI) was an underground remediation material, which had great application potential to replace nano zero valent iron (nZVI) from the perspective of economic and health benefits. However, mZVI was highly prone to gravitational settling, which limited its wide application for in situ remediation of contaminated groundwater. This paper was devoted to develop an efficient and economical groundwater remediation material based on mZVI, which should possess excellent stability, reactivity, and transportability. Thereby xanthan gum (XG) stabilized and Na 2 S 2 O 4 sulfidated mZVI (XG-S-mZVI) was synthesized and characterized with SEM, XRD , XPS , and FTIR techniques. In terms of stability, the adsorbed XG and the dispersed XG worked together to resist the sedimentation of S-mZVI. In terms of reactivity, sulfidation enhanced the electron transfer rate and electron selectivity of XG-S-mZVI, thereby improved the reactivity of XG-S-mZVI. The hexavalent chromium (Cr(VI)) removal rate constant by XG-S-mZVI was determined to be 832.4 times than bare mZVI. In terms of transportability, the transportability of XG-S-mZVI was greatly improved (~80 cm in coarse sand and ~50 cm in medium sand). Straining was the main mechanism of XG-S-mZVI retention in porous media . XG-S-mZVI in situ reactive zone (XG-S-mZVI-IRZ) was only suitable to the media with a grain size larger than 0.25 mm. This study could provide theoretical support and guidance for the implementation of IRZ technology based on mZVI.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jing Wei,Lina Wang,Yihan Liu,Da Ding,Qun Li,Yousheng Liu,Yun Chen,Meng Mao,Shaopo Deng
This study explores the potential of low-cost biochar modified with ferrihydrite and goethite for the remediation of heavily As-polluted groundwater. Combining batch experiments and synchrotron radiation-based characterization, we investigated the mechanisms of As(III) adsorption and oxidation. The modified biochars exhibited significant adsorption capacities, achieving fitted q max of 45.7 ± 3.9 mg/g for ferrihydrite-modified biochar (FhGM) and 20.2 ± 1.5 mg/g for goethite-modified biochar (GtGM) at a dosage of 1.0 g/L and an initial concentration of 10 mg/L As(III) over 24 h. Biochar facilitated approximately 30 % As(V) generation from As(III) due to enhanced electron transfer. Moreover, over 90 % of As(III) was oxidized to As(V) following the addition of H 2 O 2 , with scanning transmission X-ray microscopy revealing the distribution of As(III), and As(V) on the solid phase. In the GtGM-H 2 O 2 system, reactive oxidation species, primarily O 2 •– , served as the main oxidant. In the FhGM-H 2 O 2 system, Fe(IV) likely acted as the primary oxidizing agent. Column experiments with 0.64 g of FhGM demonstrated that, when treating 50 mg/L As-contaminated groundwater, the effluent total As concentration remained below the maximum allowable limit of 10 μg/L after 21 h. Furthermore, in the presence of H 2 O 2 , the system managed to treat 200 mg/L As-contaminated groundwater, and the effluent total As concentration exceeded 10 μg/L after 11 h. This study provides valuable insights and practical results for the remediation of high-concentration arsenic-contaminated groundwater, highlighting the effectiveness of iron-modified biochar in this application.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2016
·
IF 3.976
Weizhao Yin,Jinhua Wu,Weilin Huang,Yongtao Li,Gangbiao Jiang
This study investigated the effects of varying nitrobenzene (NB) loadings via increasing flow rate or influent NB concentration mode on the removal efficiency in zero-valent iron (ZVI) columns sterilized (abiotic) or preloaded with acclimated microorganisms (biotic). It was shown that physical sequestration via adsorption/co-precipitation and reductive transformation of NB to aniline (AN) were the two major mechanisms for the NB removal in both abiotic and biotic ZVI columns. The NB removal efficiency decreased in both columns as the flow rate increased from 0.25 to 1.0 mL min − 1 whereas the AN recovery increased accordingly, with relatively high AN recovery observed at the flow rate of 1.0 mL min − 1 . At the constant flow rate of 0.5 mL min − 1 , increasing influent NB concentration from 80 to 400 μmol L − 1 resulted in decreasing of the overall NB removal efficiency from 79.5 to 48.6% in the abiotic column and from 85.6 to 62.5% in the biotic column. The results also showed that the sequestration capacity and chemical reduction capacity were respectively 72% and 157.6% higher in the biotic column than in the abiotic column at the same tested hydraulic conditions and NB loadings. The optimal flow rates and influent NB concentrations were at 0.5 mL min − 1 and 80 μmol L − 1 for the abiotic column and 2.0 mL min-1 and 240 μmol L − 1 for the biotic column, respectively. This study indicated that microorganisms not only enhanced overall reduction of NB, but also facilitated NB sequestration within the porous media and that the optimal loading conditions for overall removal, sequestration, and reduction of NB may be different. Optimal operation conditions should be found for preferred sequestration or transformation (or both) of the target contaminants to meet different goals of groundwater remediation with the ZVI-PRB systems.
研究领域:
环境科学
·
化学工程
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS ES&T Water
·
2022
·
IF 0
Yibing Sun,Hongchao Li,Shengli Zhang,Ming Hua,Jieshu Qian,Bingcai Pan
Heterogeneous peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) are under extensive investigation for their great potential in water remediation. The understanding of the PMS activation mechanism is crucial but still debatable. Here, we describe a thorough investigation of the mechanism involved in PMS activation by using molybdenum disulfide (MoS2) as a catalyst. This MoS2/PMS system exhibited intriguing target-dependent reactivity. Further comprehensive experimental results excluded the major contributions of various possible species, including HO•, SO4•–, O2•–, 1O2, homogeneous Mo(VI), and heterogeneous Mo(VI). We then proposed a surface ≡Mo–OOSO3– complex as the major reactive species, while SO4•– derived from the decomposition of ≡Mo–OOSO3– acted as the secondary reactive species for pollutant removal. This complex could oxidize pollutants through the oxygen-atom-transfer mechanism and perform both nucleophilic and electrophilic attacks. This work provides novel perspectives for the mechanistic understanding of heterogeneous PMS-based AOPs for water remediation.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Shuyu Liu,Chunyun Gu,Jiaxin Zhang,Chaoyi Luo,Xun Rong,Gangsen Yue,Hanyu Liu,Jing Wen,Jie Ma
Persulfate (PS) is widely used as an in situ chemical oxidation (ISCO) technology for groundwater and soil remediation. While conventional theory generally assumes that PS needs to be “activated” to produce reactive radicals for pollutant degradation , herein, PS without explicit activation system was discovered for the degradation of 1,2,3-TCP with the generation of reactive oxidation species (ROS). Comparison of five common ISCO oxidants (PS, peroxymonosulfate , hydrogen peroxide, potassium permanganate, and sodium percarbonate) indicated that only unactivated PS was able to degrade 1,2,3-TCP in both pure water and 12 natural water samples. 50 μM 1,2,3-TCP degradation can be continued as long as there is enough PS (50 mM). The degradation rate of 1,2,3-TCP increased 450 % when the PS concentration increased from 10 mM to 50 mM and 500 % when the temperature increased from 25 °C to 45 ° C. Electron paramagnetic resonance (EPR) analyzes, hydroxyl radicals (·OH) probe reaction and radical quenching experiments confirmed the involvement of both sulfate radicals (SO 4 ·-) and ·OH that were responsible for 1,2,3-TCP degradation and ·OH played a more important role. HCO 3 − , Cl − and NOM are three groundwater matrix species that are most likely to inhibit PS oxidation of 1,2,3-TCP. Compared to activated PS, unactivated PS is more promising and more practical for groundwater remediation , since it has several advantages: (1) longer lifetime and better long-term availability; (2) ability of enduring contaminant degradation; (3) applicable for low-permeability zones remediation and potential to alleviate contaminant rebound or tailing problems; (4) environmental friendly; and (5) lower cost. Overall, results of this study show that unactivated PS is a promising in situ remediation technology that may be a good candidate for the most challenging low permeable zone remediation.
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
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Xiaori Fu,Xiaogang Gu,Shuguang Lu,Minhui Xu,Zhouwei Miao,Xiang Zhang,Yacong Zhang,Yunfei Xue,Zhaofu Qiu,Qian Sui
In this study, the application of sodium percarbonate (SPC) catalyzed by various chelated-Fe(II) to stimulate the degradation of benzene in groundwater remediation was investigated. Effective oxidation of benzene was achieved in CIT/SPC/Fe(II) and OA/SPC/Fe(II) systems. The reaction mechanism for benzene degradation in CIT/SPC/Fe(II) and OA/SPC/Fe(II) systems was elucidated by free radical probe compound tests, free radical scavenger tests and electron paramagnetic resonance (EPR) analysis. And hydroxyl radical (HO ) and superoxide anion radical ( O 2 - ) were confirmed as the predominant species responsible for benzene degradation. Besides, the effects of various factors, such as the solution characteristics including the presence of anions (Cl − , HCO 3 − , SO 4 2− and NO 3 − ), natural organic materials (NOM), and the initial solution pH on benzene degradation were also evaluated. The influences caused by SO 4 2− , NO 3 − , Cl − and NOM were negligible, but HCO 3 − anion had a slightly inhibitive effect in low concentration (1 mM) and an apparently inhibitive effect in high concentration (10–100 mM). However, the additions of CIT and OA eliminated the adverse influence of HCO 3 − and ensured a high benzene degradation efficiency at wider pH range. Finally, results obtained in actual groundwater test strongly demonstrated that Fe(II)-CIT and Fe(II)-OA catalyzed SPC systems are applicable for the remediation of benzene-contaminated groundwater in practice.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Yue Xu,Zhao Wang,Zizhen Wu,Xuan Li,Xu Bi,Guangying Feng,Ningyi Li
Coal gangue (CG) was encapsulated into lanthanum alginate and calcium alginate to synthesize bimetallic modified coal gangue-alginate composite hydrogel beads (La-Ca/CG-SA), and their adsorption potential towards fluoride (F − ) from groundwater was investigated. Under optimal conditions (preparation parameters: CG dosage 6 %, La/Ca ratio 1:2, and crosslinking time 24 h; operational parameters: adsorbent dosage 0.3 g L −1 , pH 6.0, and F − concentration 3 mg L −1 ), the maximum adsorption capacity of F − was achieved (15.7 mg g −1 and 87.8 %). Kinetic results indicated that the adsorption process of F − by La-Ca/CG-SA followed the pseudo-second-order model (R 2 > 0.95). Coexisting ion experiments suggested that La-Ca/CG-SA exhibited high selectivity for F − . Additionally, La-Ca/CG-SA maintained superior F − removal performance (81.5 %) after five cycles. Electrostatic interaction, inner-sphere complexation, chemical precipitation, and ion exchange were demonstrated to drive the F − immobilization. This study provides novel insights into the resource utilization of CG and the development of high-performance hydrogel adsorbents, offering potential application value in treating fluoride-contaminated groundwater.
研究领域:
环境科学
·
水处理技术
·
材料化学
·
污染控制工程
·
资源化利用
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2024
·
IF 5.3
Xuanru Li,Liuwei Wang,Bei Chen,Yuanyuan Xu,Huixia Wang,Fei Jin,Zhengtao Shen,Deyi Hou
Layered double hydroxides (LDH) show great promise for the remediation of heavy metals and metalloids in aqueous media and soils. In this study, we propose a green synthesis approach for LDH utilizing industrial waste granulated ground blast furnace slag (GGBS) and readily available magnesium oxide (MgO), and applied these green synthesized LDH for As and Cd remediation in both water and soil. The synthesized LDH were characterized via multiple approaches including SEM , HRTEM-EDS, TGA , XRD, and FTIR, demonstrating that the addition of 20% MgO in the raw materials (LDH b ) substantially improved the stability of LDH compared to LDH synthesized solely from pure GGBS (LDH a ). Batch adsorption experiments were conducted to evaluate the adsorption efficiency of LDH a and LDH b for Cd(II) and As( V ) under varying initial solution pH conditions . Results showed that as the pH increased, calcium leaching remained high while aluminum leaching gradually increased. The adsorption isotherms and kinetic studies further revealed that LDH b displayed better adsorption performance for As( V ) across different pH conditions, while both LDH showed a 100% removal rate of Cd(II) at pH ranging from 6 to 9. Both LDH a and LDH b exhibited promising immobilization effects on As and Cd in contaminated soils, with LDH a showing superior stabilization performance toward As, immobilizing 83.8% of bioavailable As in the farmland soil and 78.7% in the industrial site soil, compared to LDH b 's 54.8% and 50.6%, respectively. The findings of this study hold promise for the practical application of LDH as an efficient and environmentally friendly remediation material for contaminated water and soils containing toxic metal(loid)s.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 5
·1-9
·
IF 2.132
Ma Zhifei,Yang Yu,Yang Tianxue,Wu Daishe,Peng Xing,Xi Beidou,Jiang Yonghai,Jia Yongfeng
To evaluate the longevity of the iron-activated persulfate (PS) oxidation degradation of 2,4-dinitrotoluene (2,4-DNT), zero-valent iron (ZVI), and three different micron-scale iron oxides were used as catalysts for the activation of PS. It was revealed that 2,4-DNT was degraded more effectively by ZVI and maghemite (γ-Fe 2 O 3 ) compared to that of hematite (α-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ) catalyst treatments. Denitration of 2,4-DNT and oxidation of nitro groups as nitrate occurred by Fe 0 /PS and γ-Fe 2 O 3 /PS. When the 2,4-DNT removal rate was 1%, the generated sulfate concentrations of Fe 0 /PS and γ-Fe 2 O 3 /PS were 2.08 mg/L and 1.27 mg/L, respectively. Only micron scale γ-Fe 2 O 3 could activate PS for 2,4-DNT removal. ZVI was cycled and able to activate PS through multiple rounds. The size of the corrosion products of ZVI was more than 100 nm, and the particle size gradually increased in the cycling process. The first cycle of Fe 0 resulted in 45% removal of 2,4-DNT in 360 min. The 2,4-DNT removal efficiency (68.15%) increased after the second cycle, reaching the best removal efficiency in the fourth cycle. Oxidation products formed during degradation covered the ZVI surface, forming a shell. Adsorption of organic pollutants to this shell aids in the removal efficiency of 2,4-DNT and longevity of ZVI in groundwater.
Graphical abstract
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Xinrong Liao,Guoqiang Yu,Ruiqing Luo,Qiang Wang,Chiyang He,Shaorong Liu
Simultaneously capturing organic pollutants and heavy metal can greatly reduce the water remediation time and cost, however it is still a great challenge presently. Herein, two novel thiol/methylthio–functionalized porous aromatic frameworks were synthesized as sorbents via the Sonogashira–Hagihara reaction of 1,3,5–triethynylbenzene and 1,3,5–tris(4–bromophenyl) benzene, the subsequent chloromethylation of the phenyl rings, and the final nucleophile substitution of –Cl groups by NaSH/NaSMe. These two sorbents were characterized by FT–IR spectra, energy dispersive X-ray spectra, scanning electron microscope , nitrogen adsorption analysis, thermo–gravimetric analysis, and elemental analyses. Adsorption experiments displayed that new sorbents had high uptake abilities and fast adsorption kinetics for aromatic pollutants and mercury (II) (Hg(II)). The maximum adsorption capacity ( Q max ) of toluene and m –xylene on both new sorbents were 531.9–571.4 mg/g with the kinetic binding rate constants ( k obs ) of 0.00276–0.02422 g/mg/min, and the Q max values of Hg(II) were 148.1–180.3 mg/g with k obs of 0.00592–0.01573 g/mg/min. Moreover, new sorbents indicated high simultaneous uptake abilities for these pollutants with good reusability, and finally they were successfully applied to the simultaneous remediation of these pollutants in two simulated sewages with high and low concentration, indicating their great practical application potential in wastewater remediation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）