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Synthesis and Optical Properties of Carbon Quantum Dots Based on Terung Dayak (Solanum Ferox) Fruit Juice as Antioxidant and Metal Ion Sensor Ariefin, Mokhamat; Pasaribu, Marvin Horale; Manurung, Tety Wahyuningsih; Hakim, Muh. Supwatul; Iftitah, Elvina Dhiaul; Suma, Joy Angel Aria; Cahyani, Risfiah Ruli
Jurnal Kimia Sains dan Aplikasi Vol 28, No 4 (2025): Volume 28 Issue 4 Year 2025
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jksa.28.4.176-182

Abstract

Carbon dots (CDs) are a novel class of carbon-based nanomaterials with diverse applications due to their biocompatibility, optical properties, and chemical stability. This study aims to synthesize CDs from Terung Dayak (Solanum ferox) using a microwave-assisted method and evaluate their optical properties, metal ion sensing capability, and antioxidant activity. The CDs were synthesized with variations in microwave power and citric acid concentration, specifically: CD-a using 1 g citric acid at 600 W, CD-b using 2 g citric acid at 600 W, CD-c using 3 g citric acid at 600 W, and CD-d using 2 g citric acid at 800 W, and then characterized using UV-Vis and fluorescence spectroscopy. The results revealed strong UV absorption with maximum peaks at 250 nm for all CDs synthesized and 275 nm for CD-d, depending on synthesis conditions. The CDs exhibited fluorescence intensity influenced by microwave power, with the highest intensity observed for CDs synthesized at 800 W and 2 g of citric acid. The optical bandgap from UV-Vis spectra, determined via Tauc plot analysis, ranged from 4.03 eV to 4.71 eV, indicating quantum confinement effects for all CDs. Furthermore, CD-d demonstrated selective fluorescence quenching for Fe3+ ions, which quenched the fluorescence of the CD. Antioxidant activity was confirmed via 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging, with an IC50 value of 126 ppm for CD-d. These findings highlight the potential of Terung Dayak-derived CDs as multifunctional materials for sensing and antioxidant applications.
Immobilized L-arginine on methacrylate polymer as reusable heterogeneous catalyst for crude palm oil transesterification Erwanto, Erwanto; Warsito, Warsito; Sabarudin, Akhmad; Mardiana, Diah; Iftitah, Elvina Dhiaul
International Journal of Renewable Energy Development Vol 15, No 3 (2026): May 2026
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2026.61761

Abstract

The development of enviromentally friendly and reusable heterogenous catalyst has attracted significant attention for sustainable biodiesel production from low-cost feedstocks such as crude palm oil (CPO). This study aims to synthesize and evaluate an L-arginine immobilized methacrylate-based porous polymer as an efficient and reusable heterogenous base catalyst for CPO transesterification. In this study, a porous polymer synthesized from glycidyl methacrylate (GM) and ethylene glycol dimethacrylate (EGD), denoted as poly(GM-co-EGD), was employed as a support matrix for L-arginine immobilization to develop an efficient heterogeneous base catalyst for the transesterification of CPO. The catalyst was prepared via free radical polymerization followed by covalent immobilization of L-arginine onto the porous polymer framework. FESEM analysis revealed a well-developed interconnected porous morphology, which was further supported by textural characterization showing a high BET surface area of 650 m² g⁻¹ and a total pore volume of 2.07 cm³ g⁻¹. FTIR spectra confirmed the successful chemical bonding between L-arginine and the polymer matrix. Thermogravimetric analysis indicated good thermal stability of the polymeric catalyst up to 120 °C, suitable for transesterification conditions. The basic strength evaluated using Hammett indicators showed moderate-to-strong basicity (9.9 < H_ < 12), while quantitative back titration with benzoic acid revealed that the catalyst with a poly(GM-co-EGD):L-arginine ratio of 1:2 exhibited the highest total basicity of 1.01 mmol g⁻¹. Process optimization using Response Surface Methodology with a Box–Behnken design produced a highly accurate quadratic model (R² = 0.9992). Under optimal conditions, a biodiesel yield of 82.34 ± 1.08% was achieved, consistent with model predictions. The catalyst maintained stable performance over five consecutive cycles, demonstrating its potential as a green and sustainable catalyst for biodiesel production from CPO.
Continuous Essential Oil and Oleoresin Extraction from Star Anise (Illicium verum) by Hydrodistillation and Solvent Extraction Miranda, Fitri Ariadna Sodi; Iftitah, Elvina Dhiaul; Warsito, Warsito; Berliana, Adilatunnisa Nur Indah; Seta, Fadhlih Arya
Indonesian Green Technology Journal Vol. 11 No. 2 (2022)
Publisher : Sekolah Pascasarjana, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.igtj.2022.011.02.03

Abstract

Star anise (Illicium verum) is widely used as a medicinal herb and spice. The extracts, essential oil and oleoresin, can be cici4d produced by hydro-distillation and steam distillation, while solvent and supercritical fluid extraction can be used to extract oleoresin. In this work, the star anise is distilled to obtain the oil, subsequently, its residue is extracted by solvent extraction to get the oleoresin. Whole and grounded star anise fruit is distilled by hydro-distillation for 8, 12, 16, 20, and 24 hours, thus the highest yield is obtained at 20 hours from grounded fruit, and the highest trans-anethole content of 68.50% is obtained at 8 hours from grounded fruit. Residue from the whole fruit-distillation process is extracted by Soxhlet extraction with three types of solvent (ethanol, diethyl ether, and n-hexane) for 6 hours. The highest yield was obtained from ethanol extraction with 1.16% yield and the highest content of trans-anethol was obtained from n-hexane fraction. One sample with the highest content of anethole from whole and grounded fruit-distilled oil and oleoresin are picked, and later they are tested to cici4d measure their antioxidant capacity by Ferric Reducing Antioxidant Power Assay (FRAP). Keywords: Essential oil, oleoresin, star anise, trans-anethole