• فهرست مقالات MWCNTs-SiO2

      • دسترسی آزاد مقاله

        1 - Separation and Quantification of Hydrocarbons of LPG Using Novel MWCNT-Silica Gel Nanocomposite as Packed Column Adsorbent of Gas Chromatography
        Seyed Mojtaba Mostafavi Masoumeh Piryaei Ahmad Rouhollahi Ali Mohajeri
        In this study, a new silica gel based adsorbent was fabricated and its ability in separation and quantification of alkanes mixture was investigated. Silica gel (SiO2) is a polar absorbent which is mainly used to separate polar compounds. Also, the carbon materials such چکیده کامل
        In this study, a new silica gel based adsorbent was fabricated and its ability in separation and quantification of alkanes mixture was investigated. Silica gel (SiO2) is a polar absorbent which is mainly used to separate polar compounds. Also, the carbon materials such as activated carbon and recently carbon nanotube (CNTs), have been widely used for separation of nonpolar materials. Carbon nanotubes are nanosized carbon-based sorbents that have a high surface area and a large aspect ratio and are known to be stable at high temperatures. It is, therefore, conceivable to use of their unique properties in gas chromatography. In this work, a MWCNT-Silica gel nanocomposite was prepared by Sol-Gel process and it was used as stationary phase in gas chromatography for separation of alkanes mixture. In first part, ability of silica gel adsorbent was studied and then results were compared with new MWCNT-Silica gel nanocomposite. Finally, a quantitative investigation was done on a LPG sample and propane, 2-methylpropane, n-butane, 2,2-dimethylpropane, 2-methylbutane and n-pentane were measured by standard addition. پرونده مقاله
      • دسترسی آزاد مقاله

        2 - Separation of Aromatic and Alcoholic Mixtures using Novel MWCNT-Silica Gel Nanocomposite as an Adsorbent in Gas Chromatography
        Seyed Mojtaba Mostafavi Ahmad Rouhollahi Ali Mohajeri Masoumeh Piryaei
        The separations of alcohols with hydrophilic and hydrophobic parts, and the separation of aromatic mixtures, are extremely important processes in gas and petroleum industries. Choosing an adsorbent for performing this separation is the most important part of the process چکیده کامل
        The separations of alcohols with hydrophilic and hydrophobic parts, and the separation of aromatic mixtures, are extremely important processes in gas and petroleum industries. Choosing an adsorbent for performing this separation is the most important part of the process. Silica gel is used as an adsorbent is various techniques such as pressure swing adsorption (PSA) and gas and liquid chromatography. Due to the polarity of silica gel, it is used for the separation of polar molecules. Carbon materials such as activated carbon and recently carbon nanotube (CNTs) are widely used for the separation of nonpolar materials. In the course of this study, a new composite was fabricated using sol-gel methods. Multiwall carbon nanotubes (non-polar carbon-based adsorbents with high surface areas) were mixed with a silica gel base (a strong polar adsorbent). The composite was then used in the separation of mixtures of both aromatic hydrocarbons and alcohols. پرونده مقاله
      • دسترسی آزاد مقاله

        3 - Quantitative Determination of LPG Hydrocarbons by Modified Packed Column Adsorbent of Gas Chromatography Via Full Factorial Design
        Asghar Pasban Seyed Mojtaba Mostafavi Hanieh Malekzadeh Benyamin Mohammad Nazari
        In this study, a new silica gel based adsorbent was fabricated and its ability in separation and quantification of alkanes mixture was investigated. Silica gel (SiO2) is a polar absorbent which is mainly used to separate polar compounds. Also, the carbon materials such چکیده کامل
        In this study, a new silica gel based adsorbent was fabricated and its ability in separation and quantification of alkanes mixture was investigated. Silica gel (SiO2) is a polar absorbent which is mainly used to separate polar compounds. Also, the carbon materials such as activated carbon and recently carbon nanotube (CNTs), have been widely used for separation of nonpolar materials. Carbon nanotubes are nanosized carbon-based sorbents that have a high surface area and a large aspect ratio and are known to be stable at high temperatures. It is, therefore, conceivable to use of their unique properties in gas chromatography. Optimization of gas chromatography with modified and unmodified columns was investigated by full factorial design. According to the results of proposed design, the temperature, flow rate and carrier gas are known to be important factors affecting performance. In this work, a MWCNT-Silica gel nanocomposite was prepared by Sol-Gel process and it was used as stationary phase in gas chromatography for separation of alkanes mixture. In first part, ability of silica gel adsorbent was studied and then results were compared with new MWCNT-Silica gel nanocomposite. Finally, a quantitative investigation was done on a LPG sample and propane, 2-methylpropane, n-butane, 2,2-dimethylpropane, 2-methylbutane and n-pentane were measured by standard addition. Finally, the greatest difference between the response profiles in modified and unmodified column was determined. پرونده مقاله