COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Yanjun Ou,Shuhua Ma,Xiaohui Wang,Hao Wu,Helong Hui,Yi Zhang
China produces over 50 % of global alumina , but its dependence on imported bauxite is as high as 65 %. Local bauxite in China is of low grade. During mining, high-grade ores were sold, while low-grade ores were left piled up on site. This practice not only occupied a large land area but also caused serious pollution. Additionally, kaolinite and diaspore are embedded in a complex and dispersed distribution on the micron scale. The physical separation and ore phase dissociation of these two (kaolinite and diaspore) are very difficult, thereby preventing the economical and efficient utilization of Chinese bauxite using existing mineral flotation and sintering technologies. Based on the analysis of the molecular structure of kaolinite , this study found a significant difference in the dissolution rates of kaolinite and diaspore in a low-alkali solution. This conclusion was drawn through a combination of kinetic analysis and experimental exploration. Therefore, a new chemical pre desilication method of diaspore bauxite rich in kaolinite was proposed. The experiment found that at temperature of 180 ℃ and Na 2 O concentration of 20 g/L, the solubility of kaolinite in a low alkali solution was 3.3 g/L. After 40 minutes of reaction, the maximum dissolution of kaolinite reached 4.2 g/L. Under the same conditions, the solubility of diaspore was 0.064 g/L. The results of kinetic study showed that the activation energy of pure kaolinite dissolution reaction was 26.77 kJ/mol, which belongs to diffusion control. Conversely, the dissolution reaction activation energy of pure diaspore was 84.30 kJ/mol, which belongs to chemical reaction control . In low alkali systems, there was a significant difference in dissolution rate between the two. By optimizing the process conditions, the optimal process conditions were found. Under the optimal conditions, the aluminum silicon ratio increased from 3.22, 2.91, and 2.68–7.92, 8.42, and 8.17, respectively, by processing three types of low-grade bauxite with different particle sizes. It is noteworthy that this method can achieve a significant increase in bauxite A/S only requiring two simple processing steps: alkali dissolution and liquid-solid separation. This study not only fills the research and application gap of low alkali solutions in the field of bauxite beneficiation, but also helps to support the green and sustainable development of the world's alumina industry.
研究领域:
矿物加工工程
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材料科学与工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2024
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IF 5.8
Jinlong Wang,Shengqiang Song,Hang Liu,Ao Huang,Yunfei Wang,Mithun Nath
In the study, the solid solubility limits of Cr 3+ in the CaAl 12-x Cr x O 19 phase and leachability of any Cr 6+ safety were investigated. Analytical tools and leaching experiments were used to investigate the Al 3+ substitution in hibonite (CaAl 12 O 19 ) structure by Cr 3+ . The results showed that at Al:Cr=9:3, all the generated phases were chrome-hibonite (Ca 1.06 Cr 2.87 Al 9.07 O 18.99 ) and were also supported by the XPS and Cr 6+ leaching experiments results. However, when proportion of Cr in system increases to Al:Cr=7:5, the primary phases are Ca 1.09 Cr 3.92 Al 8.01 O 18.98 and alumina-chrome solid solution (Al 0.77 Cr 1.22 O 3 ) along with a small amount of wuboraite solid-solution (CaAl 2±x Cr 2±x O 7 , a Cr 3+ phase) and chrome-hauyne (Ca 4 Al 6 CrO 16 , a Cr 6+ phase). At Al:Cr=7:5, distilled water and 0.1 mol/L HCl leach around 1.9 mg/L Cr 6+ , but HCl showed relatively faster leaching of Cr 6+ than water and below the Chinese national standard of waste disposal of 3 mg/L. The maximum solid-solubility limit of Cr 3+ in CaAl 12-x Cr x O 19 could be considered as x =3.9.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2013
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IF 3.458
Ziwei Zhang,Xiaole Qi,Xiangbo Li,Jiayu Xing,Xuehua Zhu,Zhenghong Wu
Multilayer-coating technology is the traditional method to achieve pulsatile drug release with the drawbacks of time consuming, more materials demanding and lack of efficiency. The purpose of this study was to design a novel pulsatile drug delivery system based on the physiochemical interaction between acrylic copolymer and organic acid with relatively simpler formulation and manufacturing process. The Enalapril Maleate (EM) pulsatile release pellets were prepared using extruding granulation, spheronization and fluid-bed coating technology. The ion-exchange experiment, hydration study and determination of glass transition temperature were conducted to explore the related drug release mechanism. Bioavailability experiment was carried out by administering the pulsatile release pellets to rats compared with marketed rapid release tablets Yisu ® . An obvious 4 h lag time period and rapid drug release was observed from in vitro dissolution profiles. The release mechanism was a combination of both disassociated and undisassociated forms of succinic acid physiochemically interacting with Eudragit ® RS. The AUC0-τ of the EM pulsatile pellets and the market tablets was 702.384 ± 96.891 h ng/mL and 810.817 ± 67.712 h ng/mL, while the relative bioavailability was 86.62%. These studies demonstrate this novel pulsatile release concept may be a promising strategy for oral pulsatile delivery system.
研究领域:
药剂学
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药物递送
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生物药剂学
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药物代谢
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制剂工程
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药动学
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DOI
高影响因子
FITOTERAPIA
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2023
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IF 3.4
Yajing Wang,Tao Zhang,Jie Liu,Xianfeng Huang,Xiaojing Yan
The clinical treatment of ulcerative colitis (UC) faces great challenges due to lifetime medication. In this study, Gingerol oil was extracted and purified by the process easily scale-up and cost effective, with productivity 2.72 ± 0.38% ( w /w, versus crude drugs). The quality control of gingerol oil was fully established by HPLC fingerprint with 4 common peaks identified as 6-gingerol, 8-gingerol, 6-shogaol and 10-gingerol. The similarities of 6 batches of gingerol oil are within 0.931–0.999. The protective effects of gingerol oil are equivalent to or even stronger than that of 6-gingerol on inflammation and oxidative stress of HT-29 cells induced by lipopolysaccharide and H 2 O 2 , as well as on UC in mice caused by dextran sulfate sodium salt (DSS). Our research conclusions coincide well with the holistic view of Traditional Chinese Medicine and network pharmacology . The absorption kinetics of gingerol oil were conducted using the in situ intestinal perfusion in rats and comparable absorption were achieved in the jejunum , ileum and colon segments within 2 h. Thus, gingerol oil colon targeting pellets were prepared by extrusion-spherization technique. The cumulative dissolution behaviors and mechanisms were observed and analyzed by fitting to dissolution model. Our studies provided reliable theoretical and experimental support for the gingerol oil as reliable therapeutic choice of UC.
研究领域:
药理学
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胃肠病学
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传统中药
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药物递送系统
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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）