KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1

Browse

Settings

Subject: search.filters.subject.Hydrophobicity

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Water-tolerant cerium-modified zeolite catalyst for glycerol etherification
    (2026-02-01)
    Ausavasukhi, Artit
    ;
    Thainoi, Suwimon
    ;
    Krukrathok, Nattanitcha
    ;
    Sooknoi, Tawan
    The transformation of glycerol into alkyl ethers, which are utilized as oxygenated fuel additives, is the main topic of this study. Zeolite and cerium-modified zeolite catalysts were prepared and characterized, then evaluated for their efficacy in the etherification of glycerol with tertiary butanol. In comparison to the parent HBeta catalyst, the cerium-modified HBeta catalyst (CeHBeta), which was prepared by impregnation, demonstrated high catalytic performance in glycerol etherification, particularly at lower reaction temperatures. The cerium species can be present as charge-balancing cations and inserted into the framework. CeHBeta is therefore hydrophobic, unlike the parent catalyst. The CeHBeta catalyst may become more active if the water molecules preferentially occupying the Brønsted acid sites are reduced. While Brønsted acid sites are indispensable for the reaction, a synergistic effect with surface hydrophobicity significantly enhances catalytic performance, with CeHBeta exhibiting superior activity. Furthermore, the experiments show that a higher reaction time, molar ratio of glycerol to alcohol, reaction temperature and amount of catalyst lead to a higher selectivity for di-alkyl ether and a higher glycerol conversion.
      1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Surface hydrophobicity and catalytic performance of cerium incorporated HZSM-5 zeolite for conversion of bio-ethanol
    (2024-05-01)
    Ausavasukhi, Artit
    ;
    Sooknoi, Tawan
    Cerium incorporated HZSM-5 (CeHZSM-5) catalyst prepared by impregnation method was tested for aqueous ethanol conversion at 200–400 °C. The CeHZSM-5 catalyst was found to be very active (21.02 %Conversion), compared to the parent HZSM-5 catalyst (9.39 %Conversion), especially at low reaction temperatures (200 °C) and when fed with high water content (80 wt% ethanol). FTIR, FT-Raman, DR-UV, NH<inf>3</inf>-TPD, IPA-TPD, DSC and contact angle techniques reveal that the incorporation of cerium species into zeolites results in the acidity and hydrophilic/hydrophobic nature. Cerium species are thought to tend to migrate into ZSM-5 channels and associate with the zeolite framework. As a result, the net electrostatic charge decreases due to the presence of tetrahedral cerium atoms. Therefore, the CeHZSM-5 exhibits a hydrophobic character, compared to the parent one. The decrease in competitive adsorption of water versus ethanol feed at the Brønsted acid site may lead to an increase in CeHZSM-5 catalyst activity.
      2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Hydrothermal growth of ZnO nanostructures from nano-ZnO seeded in P(MMA-co-BA) matrix
    (2011-11-01)
    Pannasri, Piyaphan
    ;
    Siriphannon, Punnama
    ;
    Monvisade, Pathavuth
    ;
    Nookaew, Jiti
    Nano-ZnO synthesized by hydrothermal reaction were embedded in poly(methyl methacrylate-co-butyl acrylate) matrix (P(MMA-co-BA)) to produce the nano-ZnO/P(MMA-co-BA) nanocomposites via in-situ polymerization at 85 °C. The nano-ZnO/P(MMA-co-BA) nanocomposites were hydrothermal treated in the mixture solution of Zn(NO <inf>3</inf>) <inf>2</inf>•6H <inf>2</inf>O and NH <inf>4</inf>OH at 90 °C under various pH (i.e.7, 8, 9 and 10) and treatment time (i.e. 4, 6, 8, 10, 12 and 24 hrs). The nano-ZnO could act as seeding particles for hydrothermal growth of ZnO nanostructures on the surfaces of nanocomposites. The higher pH of basic solutions used in the hydrothermal treatment, the higher amount of Zn(OH) <inf>4</inf> <sup>2-</sup> nuclei would be created, leading to a modification of the ZnO morphology from nano-nuclei to nanorods, nanorods bushes (flower-like nanostructure) and nanofibers with nanospine. The increase of hydrothermal treatment time resulted in the increases of amount and length of multidirectional grown ZnO nanorods. Data of the contact angle measurement exhibited the increase of hydrophobicity of the nano-ZnO/P(MMA-co-BA) nanocomposites after hydrothermal growth of ZnO nanostructures. The nanocomposites treated at pH∈=∈10 for 24 hrs shows the highest hydrophobicity with the contact angle of 121. In addition, the thermal stability of the nano-ZnO/P(MMA-co-BA) could be improved by the formation of hydrothermal grown ZnO nanostructure on the nanocomposite surface. © 2011 Springer Science+Business Media B.V.
      1