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Jaya Hardi
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Program Studi Kimia Fakultas MIPA, Uniiversitas Tadulako Jl. Soekarno-Hatta Km. 9, Tondo Palu, 94117
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KOVALEN: Jurnal Riset Kimia
Published by Universitas Tadulako
ISSN : -     EISSN : 24775398     DOI : https://doi.org/10.22487/kovalen
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry
KOVALEN: Jurnal Riset Kimia is a peer-reviewed journal of chemistry published by the Tadulako University, Indonesia. This journal concern with publishing the original research articles, review articles, and the current issues related to chemistry. Publishing frequency 3 issues per year, in April, August, and December.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 5 Documents
 1 
Search results for , issue "Vol. 12 No. 1 (2026): April Edition" : 5 Documents clear
Effect of Extraction Time and Sodium Bisulfite on Citronella (Cymbopogon nardus) Extract: Yields, Moisture, and GC-MS Analysis Widowaty, Windy; Meidina; Sulistyorini
KOVALEN: Jurnal Riset Kimia Vol. 12 No. 1 (2026): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2026.v12.i1.17988

Abstract

This study investigated the influence of extraction time and sodium bisulfite concentration on citronella (Cymbopogon nardus) extracts using ethanol as solvent. Nine treatments (P1–P9) were evaluated for yield, moisture content, and preliminary TLC screening. The highest yield (59.94%) was obtained at 4 h with 2.5 g sodium bisulfite, while P8 (5 h, 2 g sodium bisulfite) exhibited a lower yield but higher moisture content, suggesting greater solubilization of polar compounds. ANOVA confirmed that extraction parameters significantly affected extract composition (p < 0.05). TLC results, however, produced anomalous Rf values exceeding the theoretical limit, attributed to the use of n-hexane: acetic acid (6:4) as mobile phase, which was unsuitable for terpenoid separation. Consequently, TLC was considered qualitative only. GC–MS analysis of P8 revealed 18 peaks dominated by long chain fatty acids (palmitic, oleic, cis vaccenic acids), while citronella’s characteristic terpenoids (citronellal, citronellol, geraniol) were absent, confirming volatilization losses during ethanol extraction. These findings highlight that ethanol extraction at elevated temperatures yields fatty acid rich fractions with potential functional applications, however, it is unsuitable for producing authentic citronella essential oil. Future work should optimize TLC solvent systems, extend GC–MS profiling to all treatments, and employ alternative extraction methods such as steam distillation or solvent free microwave techniques to preserve volatile terpenoids.
Hydrophobicity Properties of Silica-Dimethylsilicone Oil-Stearic Acid Based Materials Applied as Waterproof Coating Materials Suryadi, Joko; Annisa Sri Rahmawati; Derina Maulinda; Ndaru Dwiyatmoko Mukti; Andhika Putera Utama; Haryadi
KOVALEN: Jurnal Riset Kimia Vol. 12 No. 1 (2026): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2026.v12.i1.18009

Abstract

Geothermal solid waste is one of the byproduct materials from the geothermal energy process. The silica extracted from this solid waste can be utilized as a raw material for waterproof coatings. The waterproof or hydrophobic properties in this study have been studied with a formulation of silica, stearic acid, and dimethyl silicone oil. The technique of extracting silica from geothermal waste is carried out using the sol-gel method. Preparation of hydrophobic materials is carried out by mixing silica with stearic acid at a ratio of 1:3, 1:5, and 1:7 on a mass basis with the addition of dimethyl silicone oil as an emulsifier. The hydrophobic silica-dimethyl silicone oil-stearic acid materials were synthesized and characterized by functional group analysis using FTIR. The best hydrophobic properties are shown in a ratio of silica and stearic acid of 1:5. On a glass substrate, the silica-dimethyl silicone oil-stearic acid coating produced a contact angle of 110.2 °. On a fabric substrate, the coating exhibited a superhydrophobic phenomenon with a contact angle of 153.7 °.
Characterization and Biodegradation Test of Palm Kernel Meal Galactomanan-Based Bioplastics with Succinic Acid-Polyvinyl Alcohol Cross-Linking Agent Djaleha, Novelista; Rahim, Erwin Abdul; Nurhaeni; Ruslan; Sumarni, Ni Ketut; Prismawiryanti
KOVALEN: Jurnal Riset Kimia Vol. 12 No. 1 (2026): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2026.v12.i1.18014

Abstract

Environmental pollution caused by non-biodegradable plastic waste has become a major global concern, prompting the development of eco-friendly alternative materials. Bioplastics derived from natural polymers are considered a promising solution due to their biodegradability and renewability. A study has been conducted on the manufacture of bioplastics from palm kernel meal galactomannan, with the addition of succinic acid and PVA, as an effort to reduce pollution caused by plastic waste. This study aims to determine the characteristics of bioplastics, including tensile strength, elongation, Young's modulus, chemical structure, and biodegradation. Bioplastics were obtained by mixing galactomannan, PVA, and variations of succinic acid (0, 0.1, 0.2, and 0.3 g). The results showed a tensile strength of 3.61–8.76 MPa, elongation of 260.83–432.92%, and Young's modulus of 1.21–2.49 MPa. FTIR analysis confirmed the presence of ester bonds, indicating cross-linking, while the biodegradation test showed that all samples were completely degraded within 1 day. The 0.10 g variation produced the best tensile strength, while the control had the most stable surface. This galactomannan-based bioplastic has the potential to be an alternative to conventional plastic due to its good mechanical properties and very rapid degradation.
In Silico Analysis of Imidazole Derivatives Targeting Estrogen Receptor Alpha as Anti-Breast Cancer Candidates Suri, Atika; Suryani, Okta
KOVALEN: Jurnal Riset Kimia Vol. 12 No. 1 (2026): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2026.v12.i1.18031

Abstract

Breast cancer is one of the leading causes of mortality among women worldwide and is frequently associated with the overexpression of Estrogen Receptor alpha (ERalpha). This study aimed to evaluate the potential of imidazole derivatives as anticancer candidates targeting ERalpha (PDB ID: 3ERT) using an In Silico approach. Ten imidazole derivatives were analyzed through Lipinski’s Rule of Five screening, ADMET prediction, and molecular docking studies, with 4-hydroxytamoxifen employed as the positive control. Lipinski screening indicated that all compounds met the drug-likeness criteria. ADMET prediction revealed that most compounds exhibited good intestinal absorption (HIA > 85%) and adequate Caco-2 permeability, with no predicted hepatotoxicity. Molecular docking results showed that all compounds had RMSD values below 2angstroms, indicating stable interactions with the receptor. Among the tested compounds, 1-(2-Phenyl-2-propoxyethyl)-1H-imidazole demonstrated the best binding affinity (-6.3103 kcal/mol) among the imidazole derivatives; however, this value remained lower than that of the positive control, 4-hydroxytamoxifen (-8.6492 kcal/mol), which served as the primary benchmark for binding affinity comparison. Ligand–receptor interactions involved key amino acid residues within the active site of the 3ERT protein. Based on these findings, 1-(2-Phenyl-2-propoxyethyl)-1H-imidazole (compound 9) shows potential as a promising breast anticancer candidate and is recommended for further investigation through In vitro and in vivo experiments are required to verify its biological activity and evaluate its safety profile.
Photodegradation of Crystal Violet Dyes Using Fe2O3/CuO with the Addition of MEA Additive Ramadhani, Alya; Sanjaya, Hary; Nasra, Edi; Amelia, Fitri
KOVALEN: Jurnal Riset Kimia Vol. 12 No. 1 (2026): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2026.v12.i1.18047

Abstract

Synthetic dyes, including Crystal Violet (CV), are widely used in the textile and chemical industries and are increasingly released into the environment due to their toxic, mutagenic, and non-biodegradable nature. The purpose of this work is to examine the photocatalytic degradation of CV utilising Fe2O3/CuO heterojunction with monoethanolamine (MEA) as an additive. To maximise its optical and catalytic capabilities, the Fe2O3/CuO photocatalyst was synthesised using different CuO compositions and MEA volumes. Using UV-Visible Diffuse Reflectance Spectroscopy (UV-DRS) and the Kubelka-Munk technique, the band gap energy was determined. According to the findings, the incorporation of CuO did not show a pronounced effect, but it may contribute to the photocatalytic system through interfacial interactions and improved charge transfer within the Fe2O3/CuO structure. The lowest band gap value and optimal composition were found at 20% CuO, which was further reduced by adding 2 mL MEA. Tests of photocatalytic activity were conducted for 120 minutes when exposed to UV and sunshine. The results showed that CV had a high deterioration efficiency, reaching about 53.87% when exposed to sunshine. The creation of a Fe2O3/CuO heterojunction, which enhances charge separation and decreases electron-hole recombination, is responsible for the improved performance, whereas MEA enhances particle distribution and increases surface area. These results suggest that Fe2O3/CuO with MEA is a promising, economical, and eco-friendly photocatalyst for the treatment of wastewater contaminated with dyes.

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