Now showing 1 - 4 of 4
  • Some of the metrics are blocked by your 
    Item type:Publication,
    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
    ;
    ;
    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.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    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.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Chemically activated carbons derived from cashew nut shells as potential electrode materials for electrochemical supercapacitors
    (2025-06-01)
    Chaiammart, Nattapat
    ;
    Vignesh, Veeramuthu
    ;
    Thu, Myo Myo
    ;
    ;
    Maiyalagan, Thandavarayan
    Supercapacitors are widely recognized as energy storage solutions due to their high power densities and long cycle lives. Furthermore, there is growing scientific and technological interest in converting biomass waste into carbon materials for manufacturing supercapacitor electrodes. In addition to their abundance and cost-effectiveness, the appeal of carbons derived from biomass lies in their tunable porosity, which enables the rational design of carbon materials to achieve the desired performance of supercapacitors. Here, we present the synthesis of activated carbons from cashew nut shells via potassium hydroxide (KOH) activation at different temperatures (650, 750, and 850 °C). The resulting materials exhibited amorphous and predominant microporous structures. Increasing the activation temperature led to a rise in specific surface area from 1534 to 2034 m<sup>2</sup> g<sup>−1</sup> and an increased proportion of mesopores. The electrochemical properties of these activated carbons for supercapacitor applications were investigated by cyclic voltammetry, galvanostatic charge–discharge, and impedance spectroscopic techniques in a 1 M sodium sulfate (Na<inf>2</inf>SO<inf>4</inf>) electrolyte. Using a three-electrode system, the activated carbons treated at 750 °C exhibited a maximum specific capacitance of 106 F g<sup>−1</sup> at a current density of 0.5 A g<sup>−1</sup> with a good rate capability; they retained 75 % at 10 A g<sup>−1</sup> over a 1.0 V voltage window. Furthermore, a symmetric supercapacitor coin-cell, fabricated with activated carbons treated at 750 °C as the positive and negative electrodes, demonstrated an energy density of 2.43 Wh kg<sup>−1</sup> at a power density of 1002 W kg<sup>−1</sup>. The cell exhibited 87 % capacitance retention at 1.0 A g<sup>−1</sup> after 10,000 cycles. This work showcases the efficient and sustainable utilization of cashew nut shells as a carbon source for supercapacitor applications and highlights their value in a circular economy.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Biomass nanoporous carbon-supported pd catalysts for partial hydrogenation of biodiesel: Effects of surface chemistry on pd particle size and catalytic performance
    (2021-06-01)
    Udomsap, Parncheewa
    ;
    Meesiri, Sirasit
    ;
    Chollacoop, Nuwong
    ;
    Two types of cattail flower-derived nanoporous carbon (NPC), i.e., NPC activated with KOH and H3PO4, were produced and characterized using several techniques (e.g., Raman spectroscopy, ni-trogen adsorption, and X-ray photoelectron spectroscopy). The influence of the carbon support characteristics on the particle sizes and chemical states of Pd in the synthesized Pd/NPC catalysts, which affect the catalytic activity and product selectivity, was analyzed. The surface chemistry properties of NPC were the main factors influencing the Pd particle size; by contrast, the textural properties did not significantly affect the size of the Pd particles on NPC supports. The use of Pd nanoparticles supported on the rich-functionalized surface carbons obtained by H3PO4 activation led to superior catalytic activity for the polyunsaturated fatty acid methyl ester (poly-FAME) hy-drogenation, which could achieve 90% poly-FAME conversion and 84% selectivity towards mono-unsaturated FAME after a 45-min reaction time. This is due to the small Pd nanoparticle size and the high acidity of the catalysts, which are beneficial for the partial hydrogenation of poly-FAME in biodiesel. Conversely, the Pd nanoparticles supported on the high-surface-area carbon by KOH ac-tivation, with large Pd particle size and low acidity, required a longer reaction time to reach similar conversion and product selectivity levels.