MICROCHEMICAL JOURNAL
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2019
·
IF 3.206
Yajun Zhang,Xiaoliang Zeng,Xiaofang Jiang,Hanjiao Chen,Zhou Long
The cerium (Ce)-based UiO-66 metal-organic frameworks were employed for the first time as an effective catalyst for both oxidation and reduction. On one hand, selenium (Se)(VI) was efficiently photo-reduced to volatile species derived from the low lying of Ce 4f orbital and efficient generation of photo-electrons through the frameworks of UiO-66(Ce); on the other hand, the chromogenic substrate, 3, 3′, 5, 5′-tetramethylbenzydine (TMB), was oxidized based on the oxidase-like behavior of UiO-66(Ce) derived from the Ce 4+ /Ce 3+ spontaneous redox couple. The photo-reduced Se(VI) was determined by atomic fluorescence spectrometry , with a linear range of 5.0–200.0 μg/L − 1 , correlation coefficient of 0.998, and detection limit of 1.5 ng/mL − 1 obtained. The colorimetric sensing of mercury (Hg)(II) was accomplished based on the inhibition of TMB oxidation via Hg (II)-TMB interaction, with two linear ranges of 0.1–2.0 μM and 2.25–4.1 μM obtained, and a correlation coefficient of 0.993 and 0.995 obtained, respectively. The catalytic activity of UiO-66(Ce) was demonstrated to be satisfactory for both oxidation and reduction, which further explored the application of UiO-66(Ce) in the field of catalysis.
研究领域:
分析化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2018
·Vol. 5
·期 6
·1441-1453
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IF 6.087
Jingmiao Wei,Wei Zhang,Weiyi Pan,Chaoran Li,Weiling Sun
Adsorption behaviors and mechanisms of selenite [Se(IV)] and selenate [Se(VI)] on two types of zirconium metal–organic frameworks (MOFs, UiO-66 and UiO-66-NH2) were investigated using batch experiments, spectroscopic analyses, and theoretical calculations. Se(IV) adsorption was substantially greater than Se(VI) adsorption. Intriguingly, with increasing solution pH, Se(IV) adsorption increased to a maximum at pH 7, whereas Se(VI) adsorption monotonically decreased. Se(IV) adsorption was not influenced by coexisting ions except for PO43−, whereas Se(VI) adsorption was in general decreased with increasing coexisting ion concentrations. The underlying molecular binding mechanisms were elucidated via zeta potential, XPS, and FTIR analyses as well as density functional theory calculations. Se(IV) formed a strong inner-sphere complex with the MOFs via Lewis acid/base complexation between the Zr coordinatively unsaturated sites and HSeO3− or SeO32− (−59.4 to −142 kJ mol−1) and hydrogen bonding between Zr–O–C and H2SeO3 (−24.4 to −29.8 kJ mol−1). Se(VI) formed outer-sphere complexes with the MOFs through electrostatic interactions (−50.6 to −62.1 kJ mol−1). Thus, the BET surface area was the predominant factor determining the Se(IV) adsorption, whereas both the surface charge and BET surface area controlled the Se(VI) adsorption. This study provided new insights on the molecular interactions between Se(IV) and the MOFs, and revealed the distinct differences between the Se(IV) and Se(VI) adsorptions.
研究领域:
环境科学
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材料科学
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化学
✓ 已验证
DOI
高影响因子
Food Analytical Methods
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2016
·Vol. 10
·期 6
·1653-1660
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IF 2.167
Wang Xiaojun,Chen Peng,Cao Liang,Xu Guoliang,Yang Siyu,Fang Ye,Wang Guozhen,Hong Xincheng
A novel and sensitive magnetic ionic liquid-based up-and-down-shaker-assisted dispersive liquid-liquid microextraction (MIL-UDSA-DLLME) was developed for the graphite furnace atomic absorption spectrometric measurement of inorganic selenium speciation from various rice matrixes. In the first microextraction step, the magnetic ionic liquid (1-butyl-3-methylimidazolium tetrachloroferrate, [C 4 mim][FeCl 4 ]) was selected to extract the complex of Se(IV) and 2,3-diaminonaphthalene from aqueous solution by the assistance of up-and-down-shaker vortex agitator. After the microextraction step, the magnetic ionic liquid containing target analytes was collected at the bottom of the tube by applying an external magnetic field around the test tube. Under the optimized conditions, the method present has low detection limit (0.018 μg L −1 ), wide linear dynamic range (0.03–10 μg L −1 ), and good repeatability (<3.0%, n = 10) for Se(IV). The proposed methodology was applied for separation and preconcentration of inorganic selenium in standard reference materials including GBW10010 rice, GBW10043 Liaoning rice, and GBW10045 Hunan rice with satisfactory results. The developed methodology was also successfully used for the speciation of Se(IV) and Se(VI) in different rice samples with the relative recoveries within the acceptable range of 94.9–104.8% for the addition recovery tests.
研究领域:
分析化学
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环境科学
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食品科学
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产品关联
DOI
高影响因子
WATER RESEARCH
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2018
·
IF 7.051
Chao Shan,Jiajia Chen,Zhe Yang,Huichao Jia,Xiaohong Guan,Weiming Zhang,Bingcai Pan
Although the removal of Se(VI) from water by using zero-valent iron (ZVI) is a promising method, passivation of ZVI severely inhibits its performance. To overcome such issue, we proposed an efficient technique to enhance Se(VI) removal via pre-corrosion of ZVI with H 2 O 2 /HCl in a short time (15 min). The resultant pcZVI suspension was weakly acidic (pH 4.56) and contained abundant aqueous Fe 2+ . 57 Fe Mössbauer spectroscopy showed that pcZVI mainly consisted of Fe 0 (66.2%), hydrated ferric oxide (26.3%), and Fe 3 O 4 (7.5%). Efficient removal of Se(VI) from sulfate-rich solution was achieved by pcZVI compared with ZVI (in the absence and presence of H 2 O 2 ) and acid-pretreated ZVI. Moreover, the efficient removal of Se(VI) by pcZVI sustained over a broad pH range (3–9) due to its strong buffering power. The presence of chloride, carbonate, nitrate, and common cations (Na + , K + , Ca 2+ , and Mg 2+ ) posed negligible influence on the removal of Se(VI) by pcZVI, while the inhibitory effect induced by sulfate, silicate, and phosphate indicated the significance of Se(VI) adsorption as a prerequisite step for its removal. The consumption of aqueous Fe 2+ was associated with Se(VI) removal, and X-ray absorption near edge structure revealed that the main pathway for Se(VI) removal by pcZVI was a stepwise reduction of Se(VI) to Se(IV) and then Se 0 as the dominant final state (78.2%). Moreover, higher electron selectivity of pcZVI was attributed to the enhanced enrichment of Se oxyanions prior to their reduction.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 21
·21609-21618
·
IF 2.914
Tan Guangcai,Mao Yi,Wang Hongyuan,Junaid Muhammad,Xu Nan
Biochar (BC) and activated carbon (AC) were both produced from corn straw. Biochar-supported zerovalent iron (BC-ZVI) and activated carbon-supported zerovalent iron (AC-ZVI) were synthesized and applied for Se(IV)/Se(VI) removal. The sorption capacity of BC-ZVI for Se(IV) and Se(VI) was reported at 62.52 and 35.39 mg g −1 , higher than that of AC-ZVI (56.02 and 33.24 mg g −1 ), respectively, due to its higher iron content and more positive charges. The spectroscopic analyses showed that Se(IV)/Se(VI) were reduced to Se(0)/Se(-II) of less toxicity and solubility. The effects of various factors such as pH, ionic strength, co-existing cations and anions, and natural organic matter (NOM) were also investigated. Ionic strength showed no significant effect on Se(IV)/Se(VI) removal, but pH was critical. The presence of NO 3 − and SO 4 2− did not cause obvious inhibition to the removal, while PO 4 3− inhibited the sorption capacity of BC-ZVI and AC-ZVI for Se(IV)/Se(VI) significantly. Common cations (K + , Ca 2+ , and Mg 2+ ) were found to slightly enhance the removal, while NOM significantly decreased the sorption capacity of BC-ZVI and AC-ZVI for Se(IV)/Se(VI). Besides, NOM showed stronger inhibition effect on AC-ZVI than that on BC-ZVI. These results indicated that BC-ZVI, compared with AC-ZVI, could be a promising sorbent to remove Se(IV)/Se(VI) due to its low cost and high efficiency.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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