PLANT AND SOIL
·
2014
·Vol. 382
·期 1
·103-115
·
IF 3.235
Duan Dechao,Peng Cheng,Xu Chen,Yu Mingge,Sun Lijuan,Worden Natasha,Shi Jiyan,Hu Tiandou
Background and aims Metal species in rhizosphere soil profoundly influence their mobility and phytoavailability. Clarifying the speciation transformation of heavy metals helps understand their translocation and accumulation in plants. Methods Single extraction, selective sequential extraction (SSE) and X-ray absorption near-edge structure (XANES) spectroscopy were employed to investigate the speciation transformation of lead (Pb) and its influence on metal accumulation in tea plants after the addition of tea polyphenols (TPs). Results Pb content was decreased in young leaves and stems, whereas increased in roots, after TPs were amended to soil. Both SSE and XANES analysis suggested bioavailable Pb was transformed to organically bound Pb after the addition of TPs. The increased percentage of organically bound Pb might be fixed in the cell wall of plant root through a ternary complex formed between the Pb-organic matter complex and cell wall components. Therefore, Pb translocation from roots to young tissues was decreased. Conclusions Pb phytoavailability change was driven by its speciation transformation after the addition of TPs. Combined SSE and XANES spectroscopy represent powerful tools to study metal speciation transformation in plant and soil systems.
研究领域:
环境科学
·
植物学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2011
·
IF 3.068
Wenhui Xiong,Jian Peng,Yongfeng Hu
This paper presents a novel technique integrating bulk-sensitive and surface-sensitive XANES methods to distinguish between physisorption and chemisorption for phosphate adsorption onto ferrihydrite-modified diatomite (FHMD). XANES P K-edge, L-edge, and Fe M-edge spectra were obtained for reference samples (K 2 HPO 4 and FePO 4 ·2H 2 O) and test samples (phosphate adsorbed onto FHMD (FHMD-Ps) and Si-containing ferrihydrite (FHYD-Ps)). A resolvable pre-edge peak in the P K-edge spectra of FHMD-Ps and FHYD-Ps provided direct evidence for the formation of P–O–Fe(III) coordination and the occurrence of chemisorption. The resemblance between the P L-edge spectra of K 2 HPO 4 and FHMD-Ps and the marked difference between the spectra of FHMD-Ps and FePO 4 ·2H 2 O indicated the intact existence of the adsorbate and the adsorbent. The similarity between Fe M-edge spectra of FHMD and FHMD-Ps and the difference between the spectra of FHMD-Ps and FePO 4 ·2H 2 O confirmed the findings from P L-edge analyses. Therefore, chemisorption and physisorption coexisted during phosphate adsorption onto FHMD. Phosphate chemisorption occurred in the deeper zone of FHMD (from 50 nm to 5 μm); whereas physisorption occurred in the zone of FHMD shallower than 50 nm since the probing depth of XANES P K-edge method is 5 μm and that of P L-edge and Fe M-edge methods is 50 nm.
研究领域:
环境化学
·
材料科学
·
表面科学
·
吸附
·
光谱学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ying Zhao,Qingxu Li,Qiantao Shi,Beidou Xi,Xinyi Zhang,Zhiqiang Jian,Gaoting Zhou,Xiaoguang Meng,Xuhui Mao,Dejun Kang,Bin Gong
Extensive studies have been carried out on phosphate removal by zero valent iron (ZVI). Different mechanisms of phosphate removal by ZVI such as phosphate adsorption and precipitation of ferric phosphate and vivianite (Fe 3 (PO 4 ) 2 ·8H 2 O) have been reported. In this study, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray powder diffraction (XRD), and X-ray absorption near edge spectroscopy (XANES) were used to elucidate the mechanisms of phosphate removal by micron-scale zero-valent (mZVI). Time-series ATR-FTIR analysis revealed that phosphate was removed by ZVI in two steps: a) adsorption of phosphate in the first 3 days, and b) slow conversion of the adsorbed phosphate into the precipitated form in 6 days. XRD and XANES analysis determined that iron oxides, ferric ion, and ZVI with oxide layer inhibited the formation of vivianite, resulting in the formation of phosphate precipitates, such as H 2 Fe(II)P 2 O 7 . The results suggested that phosphate is removed by ZVI mainly through precipitation under aerobic conditions. The knowledge gained in this study improves the fundamental understanding of the phosphate removal processes via ZVI.
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
CHINESE SCIENCE BULLETIN
·
2006
·Vol. 51
·期 22
·2710-2716
·
IF 0.783
Yi Hongling,Zeng Xiangqiong,Cao Yan,Ren Tianhui,Kasrai M.,Bancroft G. M.
X-ray absorption near edge structure (XANES) spectroscopy has been firstly used to characterize the chemical nature of tribochemical and thermal films generated from alkyl, benzyl and acylcontaining organic polysulfides. It has been found that the thermal films generated from these polysulfides are mainly composed of FeSO 4 , and alkyl disulfides also exist in the subsurface and bulk of thermal films generated from acyl-containing polysulfides. Under tribochemical conditions, the composition of film is dependent on the molecular structure of the additives. Namely, the tribochemical film generated from alkyl polysulfide is composed of alkyl disulfide in the out surface, a mixture of FeSO 4 , FeS 2 and sulfoxide in the subsurface, and FeSO 4 in the bulk; the composition of the tribochemical film for benzyl polysulfide consists of FeSO 4 in the out surface, while the composition in subsurface and bulk is the same as the alkyl polysulfide. For acyl-containing polysulfides, the tribochemical films consist of alkyl disulfide in the out surface, and FeS 2 in the subsurface and bulk.
研究领域:
材料科学
·
摩擦学
·
表面化学
·
光谱学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Longfei Tang,Songjiang Chen,Shiwei Wang,Xiuxiang Tao,Huan He,Lei Zheng,Chenyan Ma,Yidong Zhao
The present work investigated the feasibility of heterocyclic sulfur (HS) removal for coal utilizing potassium tert-butoxide and hydrosilane system. Changes of sulfur forms with treatment time in Xinyu (XY) coal were determined by XANES . Results showed that reductions of total sulfur and organic sulfur for XY coal were 55% and 53%, respectively. >85% sulfoether and thiophene sulfur were removed after treated for 4 h, suggesting that the HS could be removed to a high extent from coal. However, contents of sulfonate and sulfonic ester increased with treatment time due to the hydrolysis and oxidation of intermediate products containing Si S bands. Furthermore, it indicated that the HS could be removed selectively from coal without destroying the macromolecular structure of coal based on analysis of desulfurization mechanism. These findings suggested that the desulfurization of refractory HS in coal could be obtained using the potassium tert-butoxide/hydrosilane reductive system, which provided a reference for desulfurization of high organic sulfur coal .
研究领域:
能源化学
·
煤化工
·
环境化学
·
应用化学
·
清洁燃料技术
✓ 已验证
DOI
高影响因子
MINERALS ENGINEERING
·
2022
·
IF 5.479
Xing-fu Zheng,Jin-lan Xia,Hong-chang Liu,Zhen-yuan Nie,Chang-qin Qin,Yu Wang,Jian-hua Chen
Elemental sulfur (S 0 ), as one of the most important intermediates formed during chalcopyrite bioleaching, can exist in a variety of allotropic forms, among which amorphous μ-S and orthorhombic ɑ-S 8 are the most common forms. Although previous studies have focused on the effect of S 0 on chalcopyrite bioleaching, how S 0 allotropes affect chalcopyrite bioleaching is unclear. Therefore, in this work, the differential effect of ɑ-S 8 and μ-S on chalcopyrite bioleaching by Acidithiobacillus ferrooxidans ( A. ferrooxidans ) was studied at the molecular and atomic levels by combining synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy, comparative transcriptome analysis and density functional theory (DFT) calculations, accompanied by the determination of solution behaviors and mineral surface morphologies. The results showed that µ-S was favorable for bacterial adsorption and that the addition of µ-S could promote the copper extraction rates by A. ferrooxidans , while the addition of ɑ-S 8 inhibited the copper extraction rates. The XANES results showed that both cases with the addition of ɑ-S 8 and µ-S could affect the formation and evolution of secondary minerals during bioleaching by A. ferrooxidans . The comparative transcriptome analysis showed that the gene expression of A. ferrooxidans was much more affected by the addition of µ-S, with more genes upregulated than ɑ-S 8 . The DFT results indicated that both ɑ-S 8 and µ-S could adsorb on the CuFeS 2 (0 0 1) surface easily, and µ-S could make the CuFeS 2 surface obviously change, while ɑ-S 8 hindered the adsorption of bacterial cells. Of note, µ-S could enhance the interaction between the CuFeS 2 (0 0 1) surface and bacterial cells with stronger bonding and more transferred electrons than ɑ-S 8 .
研究领域:
微生物学
·
矿物学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
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
·
纳米材料
·
水处理
·
吸附化学
·
环境工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Ze Li,Yidan Fu,Lina Han,Pengfei Zheng,Xiaoyuan Zeng,Peng Dong,Jing Feng,Yingjie Zhang
The insufficient d-electron density in V metal atoms limits O2 dissociation, constraining the kinetics and activity of the oxygen reduction reaction and the oxygen evolution reaction in VN-based catalysts. Herein, Co dopant was employed to modulate the electronic characteristics of the d-orbitals and associated free energy of VN, thereby further enhancing its catalytic activity. XPS and XANES spectra revealed that Co atoms replaced V and strongly bonded with neighboring N atoms, effectively regulating the local electronic structure. DFT analysis show that the Co doping strategy effectively regulates the adsorption/desorption equilibrium of oxygen reduction reaction intermediates through d-electron transfer to V atoms, while significantly lowering the activation energy barrier of the rate-determining step. Electrochemically, V0.95Co0.05N/NC/C achieved a low bifunctional index (ΔE = 0.78 V), with a half-wave potential for the ORR of 0.83 V and an OER overpotential of 380 mV at 10 mA cm–2. In Zn-air batteries, it achieved a high specific capacity (708.98 mAh gZn–1) and retained 88% initial voltage after 280 h cycling, demonstrating robust stability for practical applications. This study presents a doping strategy to modulate d-band centers in transition metal nitrides for energy conversion devices.
研究领域:
电化学
·
材料科学
·
能量转换
·
催化
·
纳米技术
·
电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Cheng-Long Ma,Zhi-Qiang Wang,Wei Sun,Li-Mei Cao,Xue-Qing Gong,Ji Yang
The surface reconstruction of iridium-based derivatives (AxIryOz) was extensively demonstrated to have an excellent oxygen evolution reaction (OER) performance in an acidic medium. It is urgent to use various spectroscopy and computational methods to explore the electronic state changes in the surface reconstruction process. Herein, the underestimated Lu2Ir2O7 was synthesized and investigated. Four typical forms of electrochemistry impedance spectra involved in the reconstruction process revealed three dominating forms of reconstructed pyrochlore in the OER stage, including the inner intact pyrochlore, mid metastable [IrO6]–[IrO6] framework, and the outer collapse amorphous layer. The enhancing electron transport efficiency of the corner-shared [IrO6]–[IrO6] framework was revealed as a critical role in acidic systems. The density of state (DOS) for the constructed [IrO6]–[IrO6] framework corroborated the enhancement of Ir–O hybridization and the downshift of the d-band center. Additionally, we contrast the pristine and reconstruction properties of the Pr2Ir2O7, Eu2Ir2O7, and Lu2Ir2O7 in alkaline and acidic media. The DOS and the XANES results reveal the scale relationship between the O 2p band center and the intrinsic activity for bulk pyrochlore in alkaline media. The highest O 2p center and the highest Ir–O hybridization of Lu2Ir2O7 exhibited the best OER performance among the Ir-based pyrochlore, up to a ninefold improvement in Ir-mass activity compared to IrO2. Our findings emphasize the electrochemical behavior of the reconstruction process for activated water-splitting performance.
研究领域:
材料科学
·
电化学
·
催化
·
光谱学
·
计算化学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 23
·13108-13117
·
IF 3.43
Ying-Ying Jiang,Zhi-Qiang Wang,Jia-Tang Chen,Jun Li,Ying-Jie Zhu,Li-Jia Liu,Xiao-Xuan Guo,Yong-Feng Hu,Shi-Sheng He,Jin Wu,Feng Chen,Tsun-Kong Sham
Adenosine triphosphate (ATP) biomolecules play critial roles in the biomineralization process during the formation of amorphous calcium phosphate composites (ACPC), and ACPC is an important drug carrier due to its significant advantages of biocompatibility and biodegradability. Hence, studying the behavior of ACPC nanodrug carriers is crucial to investigate the structural regulation of biomimetic minerals and calcium phosphate (CaP)-based drug delivery systems. However, it is difficult to probe these interactions using traditional characterization methods. In this paper, XANES analysis together with STXM successfully provided a method to reveal the interaction of ATP and drug molecules with individual mesoporous ACPC. We found that the adenosine and phosphate groups of ATP biomolecules coordinated with Ca2+ and played critical roles in the formation of ACPC; drug molecules with the –COOH groups were linked to Ca2+via carboxylic acid groups primarily by electrostatic interactions, and the N-containing ring structures within the drug molecules also coordinated with Ca2+.
研究领域:
材料科学
·
生物医学工程
·
药剂学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2025
·
IF 11.3
Jianping Lu,Baogang Zhang,Song Wang,Pan Gao,Shixiang Wang,Shungui Zhou,Fang Huang,Hailiang Dong
Vanadate [V(V)] reduction, a key process of vanadium(V) cycling and detoxification, is of geochemical interest and environmental importance, which can be driven by reducing minerals solely or by mediated by microorganisms. However, the discrepancies between abiotic and biotic processes remain poorly understood. This study demonstrated that widespread pyrite (FeS2) could reduce V(V) both directly and through microbial mediation by Thiobacillus denitrificans (T. denitrificans), with distinct outcomes. The presence of T. denitrificans accelerated V(V) reduction and improved the long-term reactivity of pyrite. XANES analysis showed that abiotic and biotic reduction resulted in an apparent oxidation state of V at 4.82 and 4.41, respectively. Microbial activity further enhanced electron transfer, supported by nicotinamide adenine dinucleotide, riboflavin and the upregulation of cnorB, nosZ, mtoA, and soxB. δ51V isotope fractionations with enrichment factors of −0.53 ± 0.06‰ (abiotic) and −0.89 ± 0.07‰ (biotic) were determined, with significant difference. Larger δ34S isotope fractionation with only δ13C change was observed in the biotic system. Bioaugmentation/biostimulation confirmed the effectiveness of pyrite in V(V) immobilization, while T. denitrificans further enhanced V(V) removal and colonized well in aquifer sediment. This work advances the understanding of couped geochemical cycling of V and pyrite and highlights the vital role of microorganisms in V remediation.
研究领域:
环境地球化学
·
生物地球化学
·
矿物学
·
微生物生态学
·
环境科学
·
电化学
·
同位素地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 9
·1416
·
IF 5.719
Yining Jia,Rong Huang,Ruijuan Qi
Numerous efforts have been devoted to realizing the high loading and full utilization of single-atom catalysts (SACs). As one of the representative methods, atom migration-trapping (AMT) is a top-down strategy that converts a certain volume of metal nanoparticles (NPs) or metal-based precursors into mobile metal species at high temperature, which can then be trapped by suitable supports. In this study, high-loading iron single atoms anchored onto carbon matrix/g-C3N4hybrid supports were obtained through a single-atom migration-trapping method based on metal–organic framework (MOF) pyrolysis. It is confirmed, by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), that the Fe(acac)3precursor is reduced to Fe single atoms (SAs), which are not only anchored onto the original N-doped carbon (NC), but also onto g-C3N4, with an Fe-N coordination bond. Further electrochemical results reveal that Fe-C3N4-0.075 possesses a better half-wave potential of 0.846 V and onset potential of 0.96 V compared to Fe-N-C, the product obtained after pyrolysis of Fe(acac)3@ZIF-8. As opposed to SAs prepared by the pyrolysis process only, SAs prepared by AMT are commonly anchored onto the surface of the supports, which is a simple and effective way to make full use of the source metal and prepare SACs with higher exposing active sites.Keywords:atom migration-trapping;single-atom catalysts;metal–organic frameworks
研究领域:
催化
·
材料科学
·
化学
✓ 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）