Journal of Environmental Sciences
·
2018
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IF 3.12
Qingyuan Hu,Yuling Zhu,Baowei Hu,Songhua Lu,Guodong Sheng
The magnetic iron oxide (Fe 3 O 4 ) nanoparticles stabilized on the biochar were synthesized by fast pyrolysis of Fe(II)-loaded hydrophyte biomass under N 2 conditions. The batch experiments showed that magnetic biochar presented a large removal capacity (54.35 mg/g) at pH 3.0 and 293 K. The reductive co-precipitation of U(VI) to U(IV) by magnetic biochar was demonstrated according to X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption near edge structure analysis. According to extended X-ray absorption fine structure analysis, the occurrence of U-Fe and U-U shells indicated that high effective removal of uranium was primarily inner-sphere coordination and then reductive co-precipitation at low pH. These observations provided the further understanding of uranium removal by magnetic materials in environmental remediation.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
Frontiers of Environmental Science & Engineering
·
2020
·Vol. 14
·期 4
·1-12
·
IF 4.053
Zhu Meng,Luo Yongming,Yang Ruyi,Zhou Shoubiao,Zhang Juqin,Zhang Mengyun,Christie Peter,Rylott Elizabeth L.
Diphenylarsinic acid (DPAA) is a phenyl arsenic compound derived from chemical warfare weapons. Macroscopic and microscopic work on DPAA sorption will provide useful information in predicting the partitioning and mobility of DPAA in the soil-water environment. Here, batch experiments and extended X-ray absorption fine structure (EXAFS) spectroscopy were used to investigate the sorption mechanisms of DPAA. The DPAA sorption data from 11 soil types was found to fit the Freundlich equation, and the sorption capacity, K f , was significantly and positively correlated with oxalate-extractable Fe 2 O 3 . The K f values of eight of the 11 untreated soils (1.51–113.04) significantly decreased upon removal of amorphous metal (hydr)oxides (0.51–13.37). When both amorphous and crystalline metal (hydr)oxides were removed from the untreated soils, the K f values either decreased or slightly increased (0.65–3.09). Subsequent removal of soil organic matter from these amorphous and crystalline metal (hydr)oxide-depleted samples led to further decreases in K f to 0.02–1.38, with only one exception (Sulfic Aquic-Orthic Halosols). These findings strongly suggest that ligand exchange reactions with amorphous metal (hydr)oxides contribute most to DPAA sorption on soils. EXAFS data provide further evidence that DPAA primarily formed bidentate binuclear ( 2 C ) and monodentate mononuclear ( 1 V ) coring-sharing complexes with As-Fe distances of 3.34 and 3.66 Å, respectively, on Fe (hydr)oxides. Comparison of these results with earlier studies suggests that 2 C and 1 V complexes of DPAA may be favored under low and high surface coverages, respectively, with the formation of 1 V bonds possibly conserving the sorption sites or decreasing the steric hindrance derived from phenyl substituents.
研究领域:
环境科学
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化学
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DOI
高影响因子
Frontiers in Microbiology
·
2026
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IF 5.8
Fanchao Meng,Ulf Skyllberg,Yangyang Li,Shusaku Hayama,Erik Björn,Yu Song
Mercury (Hg) is a global environmental concern due to its microbial conversion to methylmercury (MeHg), a potent neurotoxin that bioaccumulates in food webs and poses risks to ecosystems and human health. Thiol functional groups (RSH) play an important role in controlling Hg(II) speciation and bio-uptake in methylating bacteria, yet the spatial distribution and density of these thiols within cells remain largely unknown. We isolated subcellular fractions of the Hg methylating bacterium Geobacter sulfurreducens in the exponential growth phase, and used Hg L III -edge EXAFS (Extended X-ray Absorption Fine Structure) to quantify thiols in the extracellular medium, inner and outer membranes, periplasm and cytoplasm. The whole-cell thiol content was determined to be 1.3 × 10 −10 μmol cell −1 . The inner membrane contributed 7.1 × 10 −11 (53%), the outer membrane 1.2 × 10 −11 (9%), the periplasm 3.6 × 10 −11 (27%) and the cytoplasm 1.5 × 10 −11 μmol cell −1 (11%). The extracellular fraction contributed an additional 5.7 × 10 −11 μmol cell −1 , corresponding to 30% of the thiols of the cell culture. Local thiol density (thiols normalized to TOC in individual compartment, RSH/TOC, μmol g −1 C) was 36, 450, 140, 600 and 29 μmol g −1 C in the cytoplasm, inner membrane, periplasm, outer membrane and extracellular fractions, respectively. EXAFS analyses demonstrate Hg-thiolate coordination across all compartments, with Hg-O/N bonding and elemental Hg 0 formed at higher Hg loadings. In the periplasm, Hg-disulfide and traces of β -HgS were detected. The high thiol density at the membranes, relative to other compartments, may imply they have an important role in the retention and internalization of Hg(II). Periplasmic thiols may modulate Hg(II) transfer between membranes, and cytoplasmic thiols may regulate the intracellular availability of Hg(II) for methylation. This work provides the first compartment-resolved quantification of thiol abundances and densities in a model Hg-methylating bacterium at subcellular level, offering a mechanistic framework for understanding the speciation, bioavailability, and subcellular transformation of Hg(II) with relevance for other soft metals (e.g., Cd, Pb, Zn, Ag, and Cu).
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PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2017
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IF 5.099
Huihui Du,ChenChen Qu,Jing Liu,Wenli Chen,Peng Cai,Zhihua Shi,Xiao-Ying Yu,Qiaoyun Huang
Bacteria–phyllosilicate complexes are commonly found in natural environments and are capable of immobilizing trace metals. However, the molecular binding mechanisms of heavy metals to these complex aggregates still remain poorly understood. This study investigated Cd adsorption on Gram-positive Bacillus subtilis , Gram-negative Pseudomonas putida and their binary mixtures with montmorillonite using surface complexation model, Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and isothermal titration calorimetry (ITC). We have shown that larger amounts of Cd are adsorbed by B. subtilis than by P. putida at pH<∼6, and Cd sorption that binding to phosphate groups plays a more important role in P. putida than in B. subtilis . This remind us that we should consider the microbe species when predict the biochemical behavior of trace metals in microbe-bearing environments. The observed Cd adsorption on the binary bacteria–clay composites was more than that predicted based on the component additivity approach. When taking bacteria–clay (1:1 mass ratio) as a representative example, an approximately 68%:32% metal distribution between the bacterial and mineral fraction was found. Both the EXAFS and ITC fits showed that the binding stoichiometry for Cd-carboxyl/phosphate was smaller in the binary mixtures than that in pure bacteria. We proposed that the significant deviations were possibly due to the physical-chemical interaction between the composite fractions that might reduce the agglomeration of the clay grains, increase the negative surface charges, and provide additional bridging of metals ions between bacterial cells and clays.
研究领域:
环境科学
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微生物学
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土壤化学
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DOI
高影响因子
Journal of Materials Chemistry A
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2022
·Vol. 10
·期 16
·8887-8897
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IF 14.511
Donglin Han,Peng Zhong,Xiaorong Zhang,Lulu Jiang
Electrolytes with excellent chemical stability and high proton conductivity are key materials for protonic ceramic fuel cells and electrolyzers. Doping aliovalent cations to increase the number of oxygen vacancies is a common method to increase conductivity. However, determining proper sites for efficient doping is a matter of general concern because in many cases, there are several cation sites in complex oxides. In this work, we used EXAFS analysis to probe the changes in the local structure of proton-conducting pyrochlore oxides, La2(Nb0.4Y0.6)2O7−δ (LNY60) and La2(Nb0.35Y0.65)2O7−δ (LNY65), upon hydration and found that the coordination number of the oxygen sites in the vicinity of La and Y increased after hydration, indicating that these oxygen sites were active for the hydration reaction to introduce protons. Thereafter, the trivalent La sites were doped with divalent Ca, Sr and Ba cations to introduce more oxygen vacancies into the adjacent oxygen sites to facilitate the hydration reaction. As expected, the proton conductivity increased with increasing content of Ca, Sr and Ba. The conductivities of 2.54 at% Ca-doped LNY60 and 0.98 at% Sr-doped LNY65 were both 1.16 × 10−3 S cm−1 at 700 °C, nearly four times higher than those of the pristine oxides. These results indicate that assisted by EXAFS analysis, proper dopant sites can be determined precisely to further elevate proton conductivity in oxides.
研究领域:
材料科学
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化学
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DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 37
·14858-14864
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IF 5.7
Qiang Liu,Jingnan Wang,Kaiheng Zhao,Yongan Yang,Xi Wang
Due to their well-defined geometric and electronic structures and fully exposed active sites, single-atom catalysts (SACs) exhibit significantly enhanced catalytic activity in the field of catalysis. However, the controllable synthesis of SACs, particularly in a simple and scalable manner, presents formidable challenges. Here, we report the general synthesis of SACs containing Co, Ni, Cu, and Zn using a direct impregnation method. Atomically dispersed transition metal atoms over zeolite supports are confirmed by integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy. Detailed studies reveal that the dispersion process originates from the trapping of metal atoms by silane nests. Notably, the Co-SAC catalyst demonstrated superior catalytic performance in the industrially significant propane dehydrogenation reaction. This synthetic strategy is straightforward and amenable to large-scale production of thermally stable SACs for industrial applications.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Kaiyue Song,Chengjun Zhang,Jun Shan,Wenting Wang,Huiji Liu,Mengchang He
Simulating the adsorption behavior of Sb(V) on goethite is of great significance for predicting the mobility of Sb(V) in soil. However, there is still a lack of charge distribution and multisite surface complexation (CD-MUSIC) models that conform to the actual adsorption mechanism. Therefore, our research combined the previous EXAFS results with the SCMs and established two CD-MUSIC models (Model I, which introduced bidentate binuclear and bidentate mononuclear complexes, and Model II, which introduced bidentate mononuclear and monodentate mononuclear complexes). It is also one of the rare cases that bidentate edge- and corner-sharing adsorption complexes have been distinguished by introducing different amounts of H + . The results showed that Model I was more suitable for predicting the adsorption behavior of Sb(V) on the goethite surface than Model II. However, at low pH and high Sb(V) loading, the presence of the monodentate complex ≡FeOHSb(OH) 5 0.5- was possible due to the fast and slow two-step mechanism. Using the optimized CD-MUSIC model parameters, the contribution of surface species to the equilibrium adsorption under different conditions was determined. In the adsorption edge and adsorption isotherm simulation process, the edge-sharing bidentate mononuclear complex ≡(FeO) 2 H 2 Sb(OH) 4 was always the most important product, which was consistent with the results of extended X-ray absorption fine structure (EXAFS) analysis. The applicability of the model parameters was verified by predicting the competitive adsorption between PO 4 3− and Sb(V). The CD-MUSIC model established in the present study could be a useful tool for evaluating the equilibrium distribution behavior and environmental risk of Sb(V) in different types of soils.
研究领域:
环境科学
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土壤学
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DOI
PubMed
高影响因子
CHEMOSPHERE
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2016
·
IF 3.698
Yao-Jen Tu,Ting-Shan Chan,Hao-Wei Tu,Shan-Li Wang,Chen-Feng You,Chien-Kuei Chang
An efficient method for removing and recovering molybdenum (Mo) from water was developed by using ZnFe 2 O 4 nanoparticles . The Mo adsorption displayed a nonlinear isotherm that fitted well with the Langmuir isotherm , showing limited adsorption sites on the surface of ZnFe 2 O 4 . The adsorption of Mo(VI) was dependent on solution pH. With increasing pH, the build-up of negative charges of both adsorbent and adsorbate led to enhanced electric repulsion between them. The K -edge XANES spectra for the adsorbents collected after Mo adsorption revealed that Mo(VI) was the predominant oxidation state sorbed on ZnFe 2 O 4 , indicating that the reduction of Mo(VI) did not occur on ZnFe 2 O 4 . The different peak positions of k-space and R-space shown in K-edge EXAFS spectra demonstrated that the adsorbed Mo could be bound on the surface or be slipped in the vacancy position of the ZnFe 2 O 4 crystal. Importantly, Mo could be efficiently adsorbed from photoelectric industrial wastewater and these adsorbed Mo anions were rapidly replaced by OH − ions, implying the potential for Mo removing and recovering in industrial wastewater.
研究领域:
环境科学
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纳米材料
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水处理
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吸附化学
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环境工程
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DOI
高影响因子
APPLIED SURFACE SCIENCE
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2017
·
IF 3.387
Li-juan Pang,Rong Li,Jiang-tao Hu,Lin-juan Zhang,Ming-xing Zhang,Chen-guang Yang,Guo-zhong Wu
An innovative ultrahigh molecular weight polyethylene (UHMWPE) fibrous adsorbent was successfully synthesized via radiation grafting and applied to the selective capture of palladium ions from dilute aqueous solutions. The influence of the pH, initial Pd(II) concentration, and temperature on the adsorption performance was examined in a batch adsorption experiment. Pd K-edge extended X-ray absorption fine structure (EXAFS) spectra indicated that Pd(II) was immobilized on the adsorbent surface via a ligand exchange reaction that formed a stable UHMWPE-PMDA-Pd complex. Although the concentrations of coexisting ions (Cu(II), Zn(II), Cr(VI), Fe(III), and Ni(II)) in the solution were much higher than that of Pd(II), the adsorption capacity for Pd(II) of the as-prepared absorbent was significantly greater than that for other metal ions. Kinetic studies showed good correlation with the pseudo-second-order model. The maximum capacity for Pd(II) adsorption was approximately 221.8 mg·g −1 at 298 K. The adsorption behavior conformed to the Langmuir isotherm model. Thermodynamic studies revealed that the adsorption of Pd(II) was a feasible, spontaneous, and endothermic process.
研究领域:
材料科学
·
环境科学
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DOI
高影响因子
Environmental Science-Nano
·
2024
·
IF 5.8
Qi Cheng,Qingrui Li,Xiaoqin Li,Weizhen Liu,Zhang Lin,Liyuan Chai
Nanoscale zero-valent iron (nZVI) and modified nZVI have shown great removal capacities towards various heavy metals. However, the aging process of nZVI during the reaction is crucial for the long-term affinity and stability of heavy metals in the environment. In this study, the aging and iron oxide evolution of amorphous nZVI (A-nZVI) and nZVI during the reaction with Sb(III) were investigated and compared. The results indicated that after reacting with Sb(III), iron oxides in A-nZVI were mainly composed of γ-Fe2O3 (33.9%) and γ-FeOOH (29.8%), whereas α-Fe2O3 (24.9%) and α-FeOOH (31.8%) were dominant in the aged nZVI. The removal capacities for Sb(III) of γ-Fe2O3 (69.8 mg g−1) and γ-FeOOH (42.3 mg g−1) were both much higher than those of α-Fe2O3 (4.3 mg g−1) and α-FeOOH (8.4 mg g−1). Sb(III) was partially oxidized during the reaction, and DFT calculation showed that the adsorption energies of both Sb(III) and Sb(V) on γ-Fe2O3 and γ-FeOOH were higher than those on α-Fe2O3 and α-FeOOH. Furthermore, EXAFS analysis revealed that Sb formed an inner-sphere complex with the iron oxides in A-nZVI through the bidentate mononuclear edge-sharing structure (2E). Therefore, A-nZVI showed higher affinity and long-term stability toward Sb(III) remediation.
研究领域:
环境科学
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材料科学
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化学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Chen Ling,Zhengxiao Wang,Yixuan Song,Lichun Fu,Yanhong Zhang,Weinan Wang,Weinan Xing,Jiangang Han
The efficient removal of complexed heavy metals (HMs) from alkaline electroless plating wastewater is still challenging. A polyamine-grafted chitosan–wood flour-based composite (ACS-AWF) was optimally synthesized. Its adsorption behavior toward Ni(II) in simulated pyrophosphate (PP, the main complextant)–Ni plating wastewater and underlying mechanisms were examined. PP considerably promoted Ni(II) adsorption by up to 108.1%, and the enhancement tolerated excess PP or other substances. Ni(II) adsorption by ACS-AWF was 1.38–∼10 times that of several commercial HM-favored resins in the same complexed system. According to the liquid solute species tracking, solid chemical characterizations (eg. synchrotron radiation X-ray adsorption spectroscopy), and theoretical calculations, it was found that Ni(II), primarily as NiP 2 O 7 2− , could be captured by charge-assistant coordination with the surface polyamine. Then, the coadsorption of PP altered the interface properties via both electrostatic shielding and bridging effect, enhancing Ni(II)–amine coordination efficiency. A dinuclear multilayer coordination structure [-amine–Ni–PP–Ni–amine-] was proposed as the dominant Ni(II) binding mode in the presence of PP. Ni(II) and PP could be sequentially desorbed from ACS-AWF using gradient elution with ＞95.5% Ni(II) purity. ACS-AWF was then stably reused in five cycles (capacity loss ＜10%). These results may guide adsorbent design and application in HM purification and recycling from complexed wastewater.
研究领域:
环境科学
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材料科学
·
化学工程
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产品关联
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Jinwen Qiu,Xiaokang Hou,Yuan Ren,Chengshuai Liu,Fangyuan Meng,Jyh-Fu Lee,Yu-Jung Lin,Ziyuan Huang,Huanxin Ma,Zhenqing Shi,Chunhua Feng
The photoinduced transformation of ferrihydrite is an important process that can predict the geochemical cycle of Fe in anoxic environments as well as the fate of trace elements bonded to Fe minerals. We report that the photooxidation of sulfite by UV irradiation produces hydrated electrons (super-reductants), which significantly promote ferrihydrite reduction to Fe(II), and SO 3 •− (a moderate oxidant), enabling its further oxidation to more crystalline Fe(III) products. The experimental results show that the concentration of sulfite was key in influencing the rate and extent of surface-bound Fe(II) formation, which ultimately determined the distribution of individual products. For example, fitting of the Mössbauer spectroscopy data revealed that the relative abundances of mineral species after 8 h of treatment in the UV/sulfite systems were 41.9% lepidocrocite and 58.1% ferrihydrite at 2 mM SO 3 2− ; 41.8% goethite, 28.2% lepidocrocite, and 29.1% ferrihydrite at 5 mM SO 3 2− ; and 100% goethite at 10 mM SO 3 2− . The combined results of the chemical speciation analysis and the Cd K-edge EXAFS characterization provided compelling evidence that Cd was firmly incorporated into the structure of newly formed minerals, particularly at high sulfite concentrations. These findings provide an understanding of the role of UV/sulfite in facilitating ferrihydrite transformation and promoting Cd stabilization in oxygen-deficit soils and aquatic environments.
研究领域:
环境科学
·
地球化学
·
矿物学
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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）