APPLIED SURFACE SCIENCE
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2016
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IF 3.15
Jin Feng,Qiang Wang,Dongliang Fan,Lirong Ma,Deli Jiang,Jimin Xie,Jianjun Zhu
In order to investigate the roles of three-dimensional network structure and calcium on Ni catalysts, the Ni, Ni-Al 2 O 3 , Ni-Ca-Al 2 O 3 xerogel catalysts were successfully synthesized via the fast sol-gel process and chemical reduction method. The crystal structure of three different catalysts was observed with X-ray powder diffraction (XRD). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption were employed to investigate the role of network structure of xerogel catalysts and the size distribution of Ni nanoparticles. The catalyst composition was determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) measurement and energy-dispersive X-ray spectroscopy (EDS). Temperature-programmed reduction (TPR) experiments were carried out to investigate the reducibility of nickel species and the interaction between nickel species and alumina. The catalytic hydrogenation of p -nitrophenol to p -aminophenol was investigated over the prepared nickel-based xerogel catalysts. The conversion of p -nitrophenol was monitored by UV spectrophotometry and high performance liquid chromatography (HPLC). The results show that the catalysts are highly selective for the conversion of p -nitrophenol to p -aminophenol and the order of catalytic activities of the catalysts is Ni < Ni-Al 2 O 3 < Ni-Ca-Al 2 O 3 . The catalysts were recycled and were used to evaluate the reutilization.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Jing Yang,Qian Guo,Lei Li,Ruixue Wang,Yucheng Chen,Xingrun Wang
Compare to the content of Cr(VI), the distribution of specific Cr(VI) species in soil is rarely paid attention to, which may lead to an inaccurate environmental risk assessment of Cr(VI) contaminated soil or inability to meet stringent requirement for soil remediation . Herein, to reveal the primary mechanisms and factors controlling the evolution of Cr(VI) species in soil, the distribution of Cr(VI) and Cr(III) species in soils with different particle sizes and textures was systematically investigated by using a modified sequential extraction procedure and spectroscopy characterizations (e.g., SEM-EDS mapping). The results show that a significant proportion of Cr(VI) can be captured by minerals containing exchangeable calcium ions and metal oxide hydrates in the soil, forming a relatively stable adsorbed Cr(VI). Also, a small fraction of Cr(VI) can precipitate as calcium chromate with free calcium ion which is the most stable Cr(VI) species in the soil. The majority of Cr(VI) discharged into soil tends to be reduced by ferrous ions or minerals containing ferrous ions with a product of Fe(III)-Cr(III) coprecipitate. Therefore, the speciation of Cr in the soil is closely correlated to Fe and Ca. After the equilibrium of adsorption, precipitation, and reduction reactions of Cr(VI), the rest of Cr(VI) retains as the form of its original water-soluble state in soil. The evolution of Cr(VI) species and the content of specific Cr species in soil are mainly determined by the contents of iron, exchangeable calcium ions and metal oxide hydrates, which effect the Cr(VI) reduction, precipitation and adsorption, respectively.
研究领域:
环境科学
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土壤化学
✓ 已验证
DOI
PubMed
高影响因子
Materials Today Communications
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2024
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IF 3.7
Yufei An,Yiping Su,Gang Li,Shuoyang Liang,Yingying Cai,Ruiheng Zhang,Xuehua Shen,Feng Yan,Zuotai Zhang
CO 2 capture through mineral carbonation extends the applicability of carbon sequestration by enabling storage in various cementitious materials derived from solid wastes. Calcium-containing cementitious materials receive extensive attention due to their potential for carbon capture, however, the underlying mechanisms both decalcification and carbonation during composition-structure evolution remain to be fully elucidated. Herein, a mineral carbonation strategy was reported to enhance carbon uptake performance, depending on the evolution stage of calcium (alumino) silicate hydrates (C-(A-)S-H) gel induced by alkali activation. Sequential dynamic monitoring and experimental characterizations confirmed that the decalcification and carbonation processes are closely linked to Ca-bonding states within the C-(A-)S-H structure. The results indicate that the short chains of alumino-silicate and the majority of the weakly bonded Ca phases are more prone to carbonation. Estimation of carbonation capacities also revealed that samples with 3h-activation exhibit the highest carbonation capacities (80.5 %), showing the higher carbonate potential with free Ca and weakly bound Ca (e.g. Ca(OH) 2 and interlay Ca in tobermorite-like structure) than samples with more intralayer Ca. Our work can provide new insights into the understanding of alkali activation induced decalcification and the improvement on carbonation capacities in early-formed C-(A-)S-H analogues.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2014
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IF 3.785
Ziyun Shan,Yinhe Tan,Lingzhen Qin,Ge Li,Xin Pan,Zhouhua Wang,Xiu Yu,Qinruo Wang,Chuanbin Wu
To develop reverse microemulsion as a potential strategy for pulmonary delivery of salmon calcitonin (sCT) in HFA134a propellant of pressurized metered dose inhalers (pMDIs), pluronic P85 (P85) was chosen as the most appropriate surfactant to form microemulsions containing sCT. Formulation parameters, including the surfactant and ethanol content, water content, and sCT loading, were optimized to obtain two desired pMDI formulations A and B with clear and transparent appearance, Tyndall effect, good physical stability and aerosolization properties. Aerosolization properties of the optimized pMDIs were assessed by next generation impactor (NGI) and twin-stage impactor (TSI), and the dose of sCT in each stage was assayed by HPLC. The fine particle fraction (FPF) of formulations A and B were both at the range of approximately 28.0–36.0%. Cytotoxicity studies indicated the cell viability determined by MTT assay only slightly dropped when the A549 cells were exposed to the pMDI formulations. Pharmacological study performed on the male Wistar rats showed the intratracheal administration of the microemulsion pMDIs containing sCT exhibited similar but prolonged hypocalcemic activity compared with the intravenous injection of sCT solution. Therefore, such reverse microemulsions are potential for pulmonary delivery of therapeutic peptides using HFA-pMDIs.
研究领域:
药剂学
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药物递送系统
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药理学
✓ 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）