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Author: search.filters.author.Kaewtrakulchai, NapatSubject: search.filters.subject.Chemical activation

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    Bimetallic PdNi catalyst on cattail Leaves-Derived nanoporous carbon support for synthesis of partially hydrogenated fatty acid methyl ester (H-FAME)
    (2024-06-01)
    Longprang, Tripob
    ;
    Kaewtrakulchai, Napat
    ;
    Kiatkittipong, Worapon
    ;
    Srifa, Atthapon
    ;
    Chollacoop, Nuwong
    Cattail leaves (CL) have been used as a carbon source to synthesize nanoporous carbon (NPC) support with high surface area (S<inf>BET</inf> = 2002.12 m<sup>2</sup>g<sup>−1</sup>) via hydrothermal carbonization and potassium hydroxide (KOH) activation. The studied catalysts, including monometallic Pd/NPC and Ni/NPC, and bimetallic PdNi/NPC, were synthesized and characterized by using several techniques (e.g., scanning electron microscopy, transmission electron microscopy, nitrogen sorption, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction). Their catalytic activity toward partial hydrogenation of palm biodiesel to H-FAME was tested, and the liquid product composition, cloud point, and oxidation stability were determined. The studied catalysts have a high porosity with the S<inf>BET</inf> of approximately 2037.34–2187.96 m<sup>2</sup>g<sup>−1</sup> led to excellent metal dispersion. Although Ni did not show high catalytic activity compared to Pd, Ni incorporated with Pd as PdNi/NPC catalyst significantly increased the cis-C18:1 selectivity and prevented the catalytic deactivation during the partial hydrogenation. The oxidation stability of palm biodiesel feedstock was increased from 13.69 to 17.12 h while the cloud points adversely increased by only 3 degrees from 12 to 15 °C (still lower than 16 °C of the Thai industrial recommendation) with bimetallic PdNi/NPC catalyst. The main benefit of bimetallic PdNi/NPC over monometallic Pd/NPC and Ni/NPC is shown through not only higher C18:2 conversion but also much higher cis-to-trans ratio of C18:1 resulting in higher oxidation stability with acceptable compromise on the cloud point increasing. Consequently, the produced palm H-FAME can be used at a high blend ratio.
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    Synthesis of nanoporous carbon from brewer waste by hydrothermal carbonization assisted chemical activation for carbamazepine adsorption
    (2024-06-01)
    Apinyakul, Naruemon
    ;
    Chanpee, Sirayu
    ;
    Kaewtrakulchai, Napat
    ;
    Khemasiri, Narathon
    ;
    Eiad-ua, Apiluck
    Nanoporous carbon (NPC) has gained significant attention in wastewater treatment due to its effectiveness. The adsorption process, known for its simplicity, stability, and cost-effectiveness, is widely recognized as an efficient method for removing carbamazepine (CBZ) residues accumulate in the environment. However, the application of NPC is often hindered by challenges in the regeneration process after use, as well as issues related to large surface area, pore size, and functional groups. Fortunately, the samples in this study not only maintained their adsorption efficiency but also demonstrated the ability to be regenerated multiple times. Herein brewery waste was subjected to hydrothermal treatment at 200 °C for 1 h and followed by KOH and NaCl activation with different KOH:NaCl (w/w) ratios of 5:0, 4:1, 3:2, 1:1, 2:3, 1:4, and 0:5 to optimize the properties of malt husk derived nanoporous carbon (NPC). The optimal condition KOH:NaCl ratio of 1:1 had a maximum specific surface area of 906 m<sup>2</sup>/g with a total pore volume of 0.252 cm<sup>3</sup>/g. According to the adsorption test, the CBZ adsorption isotherm was well-fitted to the Langmuir model (R<sup>2</sup> = 0.976) kinetic data were consistent with the pseudo-second-order model (R<sup>2</sup> = 0.995). This suggests that the adsorption mechanism involves monolayer adsorption and chemisorption interaction. The Gibbs free energy and enthalpy of CBZ adsorption by NPC were found to be spontaneous and endothermic. The regeneration test revealed a 95.35% decrease in the adsorption capacity of NPC after 5 repeated cycles. Consequently, the study suggests a potential application of nanoporous carbon from MH as an alternative adsorbent for removing carbamazepine in wastewater.
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