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    Item type:Publication,
    Biodiesel Washing by the Prototype of a Biodiesel Washing Machine with Biochar
    (2025-11-01)
    Fonghiransiri, Surasak
    ;
    Chungcharoen, Thatchapol
    ;
    Choola-Aied, Orasa
    ;
    Srisang, Siriwan
    ;
    Srisang, Naruebodee
    Currently, the prevalent technique for biodiesel washing entails the utilization of water in the purification process. Nevertheless, this method incurs substantial biodiesel loss and gives rise to wastewater, posing potential environmental consequences. Hence, this study aimed to utilize biochar for removing impurities from biodiesel by using a prototype of a biodiesel washing machine with biochar. The effects of the propeller blade number, propeller blade angle, and mixing time on the capability to eliminate impurities in biodiesel were elucidated. The results indicated that the biodiesel washing machine can increase biodiesel yield by up to 2.49% (91.54%) compared to the water washing process (89.05%). The increased propeller blade number, angle, and mixing time can improve the acidity (24.50-64.04%) and water content removal (42.61-79.56%). Consequently, this led to a decrease in density (865.85-886.83 kg/m<sup>3</sup>) and viscosity (3.997-4.321 cSt). The conditions with the best biodiesel properties were five propeller blades, a propeller blade angle of 60 degrees, and a mixing time of 30 minutes. These conditions provided the 63.88% acid removal, 79.49% water content removal, viscosity of 878.92 kg/m<sup>3</sup> and density of 4.208 cSt. Moreover, the methanol and glycerol contents were 0.02% wt. and 0.04% wt., respectively. These properties meet the ASTM 6751 and EN 14214 biodiesel standards.
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    Item type:Publication,
    Low-Cost Activated Carbon for Methylene Blue Adsorption Using Inert Gas-Free Carbonization and Microwave Activation
    (2025-01-01)
    Kongtragoul, Pornprapa
    ;
    Keeratirawee, Kanchalar
    ;
    Choola-Aied, Orasa
    -This study investigated the preparation of activated carbon from spent coffee grounds for methylene blue adsorption using inert gas-free carbonization and microwave activation. Spent coffee grounds were obtained from a local coffee shop in Pathio, Chumphon, Thailand. The coffee grounds were pretreated with 1M H<inf>2</inf>SO<inf>4</inf> before undergoing carbonization at 600 ºC for 3 h in a limited-oxygen atmosphere. The obtained carbon materials were chemically activated with zinc chloride (ZnCl<inf>2</inf>) and physically activated using a microwave-assisted method at 300 W for 180 seconds. The adsorption of methylene blue was evaluated using a batch method. Methylene blue adsorption contact time, effect of pH, and initial concentration were investigated. The maximum adsorption capacity of the activated carbon for methylene blue removal was found to be 29.24 mg/g. The prepared activated carbon exhibited a BET surface area of 70.08 m<sup>2</sup>/g and reached equilibrium in 120 min at the optimum pH of 9. The adsorption isotherm was consistent with the Freundlich model, while the adsorption kinetics followed a pseudo-second-order model. The findings indicate that activated carbon is a cost-effective and efficient adsorbent for methylene blue removal from aqueous solutions.