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Journal : Walisongo Journal of Chemistry

UTILIZATION OF BAGASSE ASH FOR THE PREPARATION OF SILICA AEROGEL/MgO COMPOSITES THROUGH AMBIENT-PRESSURE DRYING Azhar, Istighfarin Meilidya; Nazriati, Nazriati; Kusumaningrum, Irma Kartika
Walisongo Journal of Chemistry Vol. 8 No. 2 (2025): Walisongo Journal of Chemistry
Publisher : Department of Chemistry Faculty of Science and Technology UIN Walisongo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21580/wjc.v8i2.27564

Abstract

This study presents the preparation of silica aerogel/MgO composites using bagasse ash as a silica source and MgCl₂·6H₂O as the MgO precursor. Sodium silicate was extracted from bagasse ash and converted into silicic acid through ion-exchange treatment. Silica aerogel formation was achieved through gelation, followed by surface modification using TMCS and HMDS. Magnesium oxide was incorporated via co-precipitation with MgCl₂·6H₂O and subsequently stabilized through calcination. The composites were characterized using FTIR, XRD, and BET–BJH analyses. XRD results revealed a hybrid amorphous–crystalline structure, with silica predominantly in the amorphous phase and MgO in the crystalline phase. BET analysis showed a pore volume of 0.50 cm³/g and a specific surface area of 121.99 m²/g, while the pore-size distribution confirmed its mesoporous nature. FTIR spectra indicated the presence of functional groups corresponding to Si–O–Si, Si–C, C–H, and Mg–O, confirming the successful integration of MgO into the silica aerogel framework. These findings demonstrate the successful preparation of silica aerogel/MgO composites from bagasse ash under ambient-pressure drying conditions.
NaOH-MODIFIED ACTIVATED CARBON FROM CORNCOBS AS A HETEROGENEOUS CATALYST: SYNTHESIS AND APPLICATION IN ULTRASOUND-ENHANCED TRANSESTERIFICATION OF USED COOKING OIL Santana, Rosanina Kartika; Aliyatulmuna, Adilah; Nazriati, Nazriati; A'yun, Amalia Qurrata
Walisongo Journal of Chemistry Vol. 8 No. 2 (2025): Walisongo Journal of Chemistry
Publisher : Department of Chemistry Faculty of Science and Technology UIN Walisongo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21580/wjc.v8i2.28915

Abstract

Biodiesel is an alternative fuel composed of fatty acid methyl esters that can be synthesized from renewable sources and offers lower combustion emissions compared to fossil fuels. In this study, biodiesel was produced via a transesterification reaction using a basic heterogeneous catalyst derived from corncob carbon, which was activated and surface-modified with NaOH to create active catalytic sites. XRD and FTIR analyses confirmed the presence of Na₂CO₃ and Na₂O, while SEM-EDX revealed a porous surface morphology with uniformly distributed sodium. Used cooking oil (UCO) served as the triglyceride source after undergoing degumming, neutralization, and adsorption processes to reduce free fatty acid (FFA) content. The transesterification reaction was conducted in an ultrasonic water bath using the reflux method at 60°C with an oil-to-methanol molar ratio of 1:12. The optimum reaction conditions were achieved using 0.5 wt% catalyst and a reaction time of 120 minutes, yielding 73.15% biodiesel. The quality of the biodiesel produced under optimum conditions was evaluated based on density, viscosity, acid value, and calorific value, which were 857 kg/m³, 3.8743 cSt, 0.2504 mg KOH/g, and 11,168 cal/g, respectively. These values comply with the quality requirements specified in SNI 04-7182-2015. GC-MS analysis confirmed that the major components of the biodiesel were methyl oleate and methyl palmitate. The utilization of corncob waste as a sustainable catalyst support, combined with alkali modification and ultrasonic enhancement, offers improved catalytic efficiency under mild operating conditions. This eco-friendly catalyst demonstrates strong potential for green catalytic processes in renewable energy development.