Faculty of Humanities and Sciences

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    Catalytic graphitization in nanocast carbon monoliths by iron, cobalt and nickel nanoparticles
    (Pergamon, 2018-08-01) Thambiliyagodage, C. J; Ulrich, S; Araujo, P. T; Bakker, M. G
    Hierarchically porous carbon monoliths containing metal (Fe, Co, Ni) nanoparticles were synthesized in a one-pot synthesis through a nanocasting technique using silica (SiO2) as the template. The macropore structure of SiO2 has been replicated in nanocast carbon and N2 adsorption analysis shows that the monoliths have high surface area, high mesopore volume, and that micropores are also present. The temperature effect on catalytic graphitization was studied by using x-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectroscopy. It is observed that iron was capable of producing turbostratic carbon at 500 °C, while turbostratic carbon was produced at temperatures of 700 °C when cobalt and nickel are present. Iron, cobalt, and nickel were found to be good graphitization catalysts with the order of catalytic activity being iron > cobalt > nickel. Raman spectroscopy experiments provide insight into the degree of ordering of the carbon of each sample and are in agreement with the results from the other techniques: with increasing pyrolysis temperature, with and without the presence of metals, ordering of amorphous carbon is confirmed. Detailed analysis of the Raman spectroscopic data showed clear differences between the metal catalyzed and non-catalyzed samples enabling the contributions from the two different mechanisms to be clearly distinguished.
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    PublicationOpen Access
    Leaching of ilmenite to produce titanium based materials: a review
    (Springer International Publishing, 2021-12) Thambiliyagodage, C. J; Wijesekera, R; Bakker, M. G
    Naturally available ilmenite mineral is being used as a starting material to produce titanium based products that have wide applications. Transformation of ilmenite to diferent titanium based materials by strong and weak acid, and base digestion, is discussed. Efects of temperature, concentration of acid/base, reaction time on dissolution of ilmenite are extensively reviewed. Characterization of the starting materials, intermediates and the products by x-ray difraction, thermogravimetry, brunauer–emmett–teller surface area analysis, and scanning electron microscopy are presented. Further, advantages and disadvantages associated with the digestion methods are discussed.
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    PublicationOpen Access
    Synthesis of mesoporous silica nanoparticles derived from rice husk and surface-controlled amine functionalization for efficient adsorption of methylene blue from aqueous solution
    (Elsevier, 2021-01-01) Usgodaarachchi, L; Thambiliyagodage, C. J; Wijesekera, R; Bakker, M. G
    Mesoporous silica nanoparticles (MSN) were synthesized using rice husk (RH) as the raw material via sol-gel pathway using cetyltrimethylammonium bromide (CTAB) as the structure directing agent. Silica nanoparticles were successfully functionalized with 3-aminopropyl triethoxysilane (APTES) via in-situ and post functionalization methods. Synthesized nanoparticles were characterized by X-Ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The amorphous silica nanoparticles were of 50–60 ​nm in diameter with a surface area of 150 ​m2/g, pore volume of 0.237 ​cm3/g and average pore size of 3.62 ​nm. Morphology and textural parameters were changed upon functionalization. The equilibrium adsorption capacity of MSN-A (4.94 ​mg/g) to adsorb 10 ​mg/L methylene blue (MB), was higher than in amine functionalized silica nanoparticles. The influence of experimental factors such as pH, adsorbent dosage, and initial MB concentration on adsorption of MB to MSN-A were studied. The equilibrium data for MB adsorption on mesoporous silica nanoparticles well fitted to Langmuir equation, with a maximum monolayer capacity of 19.26 ​mg/g. The adsorption of MB could be best described by the pseudo-second order model. The results indicate that MSN-A is a potential mesoporous material fabricated by cheap natural resources to remove MB from aqueous solutions.