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Jaya Hardi
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INDONESIA
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 320 Documents
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Studi Awal Sintesis ZnO/SiO2 dengan Silika dari Limbah Padat Geothermal dan Uji Performansinya dalam Penghilangan Metilen Biru : Preliminary Study of ZnO/SiO2 Synthesis with Silica from Geothermal Solid Waste and Its Performance Test in Methylene Blue Removal Paramitha, Tifa; Joko Suryadi; Rahma Ardelia Raissa; Teguh Aditya Nugraha; Nirmala Utami
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16557

Abstract

Industrial development impacts environmental problems, such as the emergence of wastewater containing methylene blue. In this research, SiO2 was composited with ZnO to remove methylene blue. The steps of this study include SiO2 extraction from geothermal solid waste, ZnO/SiO2 synthesis, and methylene blue removal test. The process of extracting SiO2 from geothermal solid waste used the sol-gel method. The FTIR analysis showed that SiO2 contains siloxane group (Si-OH) and silanol group (Si-O-Si). ZnO/SiO2 synthesis was done by making SiO2 suspension and continued with adding the addition of several Zn(NO3)2.6H2O. The FTIR analysis of ZnO/SiO2 showed no absorption at the wavenumber 960 cm-1 and there is a shoulder around the number 950 cm-1 which indicates the vibration of Si-O-Zn. Meanwhile, methylene blue removal tests were carried out on artificial wastewater. Based on the research results, the highest percent removal (99%) was obtained under operating conditions, including a dose of 500 mg/L, pH 10, and contact time of 30 minutes. Based on box-benkhen analysis, it is known that dose and pH singularly affect the percent removal, while contact time does not affect the percent removal. The optimization results obtained optimum conditions for methylene blue removal at a dose of 581.952 mg/L, pH of 10, and contact time of 30 minutes. Percent removal in conditions without irradiation and with irradiation of UV light were 98.758% and 99.178%. It shows that the adsorption process is the main process in removing methylene blue, while the photocatalytic process has little effect because it is possible that only a small amount of ZnO can attach to the surface of SiO2.
The Effect of Solvent-to-Coffee Ratio on Caffeine Content in Ethyl Acetate Extracts of Arabica Gayo Coffee Beans Soeswanto, Bambang; Sihombing, Rony Pasonang; Suryadi, Joko; Hariyadi, Tri; Paramitha, Tifa; Yusuf, Yusmardhany; -, Alfiana Adhitasari
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16573

Abstract

This paper studies the optimal ratio that gives the highest caffeine amount and improves the efficiency and quality of extraction from Arabica Gayo coffee beans. No previous studies have explored the best ratio of Gayo Arabica coffee beans to ethyl acetate solvent for extracting caffeine. The paper explains the method used, which has four main steps: preparing materials, extracting and measuring caffeine, and analyzing the results. The paper presents the experimental findings and discusses how different ratios affect caffeine content in Arabica Gayo coffee beans. It uses statistics to show significant differences between the ratios and compares them using Tukey tests. The paper concludes that the best solvent-to-coffee ratio for maximizing caffeine in ethyl acetate extracts is 1:5, resulting in a concentration of 1411.1 ppm. This ratio gives the best balance between caffeine yield and solvent usage.
Penurunan Logam Fe dan Co Pada Kerang Hijau (Perna viridis) dengan Metode Perendaman Larutan Belimbing Wuluh: Reduction Fe and Co Metals in Green Mussels (Perna viridis) by Soaking in Starfruit Solution Widiyanto, Holisha; Asad, Hafidz Al; Sriwijayanti; Susvira, Dian; Situmeang, Boima
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16586

Abstract

Green mussels with the Latin name Perna viridis are an animal that lives in the ocean and is a type of shellfish that is widely consumed by the public. Along with time, the emergence of factories that can pollute the oceans can cause contamination of marine life in it, one of the pollutants is the heavy metals of Fe and Co. The accumulation of heavy metals Fe and Co in green mussels can be toxic to people who consume them. This study aims to determine the concentration of heavy metals Fe and Co in green mussels before and after immersion in starfruit solution. Tests for immersion of the starfruit solution were carried out at 15, 30, and 45 minutes, then the destruction results were analyzed using inductively coupled plasma (ICP) with the calibration curve method. The Fe content in the green mussel sample before treatment was 2.946 mg/kg and the Co content in the green mussel sample before treatment was 2.6081 mg/kg. After soaking in starfruit solution for 15, 30, and 45 minutes, the Fe metal was 1.572 mg/kg, 1.275 mg/kg, and 1.035 mg/kg and the Co metal was 1.572 mg/kg, 1.275 mg/kg, and 0.683mg/kg. Research of immersing starfruit solution with soaking for 15, 30, and 45 minutes is effective in reducing levels of heavy metals Fe and Co in green mussels. The highest reduction was observed during a 45-minute immersion, with a decrease of 64.87% for Fe and 73.81% for Co, respectively.
Ekstraksi Komponen Lipid dari Mikroalga Nannochloropsis oculata dan Nitzschia sp. dengan Metode Sokletasi dan Bligh Dyer: Extraction of Lipid Components from Nannochloropsis oculata and Nitzschia sp. Microalgae with Soxhletation and Bligh Dyer Methods Stepanus, Jamius Bin
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16596

Abstract

Dependence on fossil energy sources as non-renewable energy will trigger the threat of an energy crisis in Indonesia in the future. The solution to this issue is through the development of renewable energy and one of them is through the exploration and utilization of biomass such as microalgae. Microalgae have a high lipid content (4-77%) and have potential as raw materials for producing biofuel (biodiesel, bioethanol, and biogas). Lipids can be converted into biodiesel through acid or base-catalyzed esterification and transesterification reactions. The aim of this research was to determine the percentage of lipid components, namely free fatty acids (FFA), monoglycerides (MAG), diglycerides (DAG), and triglycerides (TAG) from microalgae extracts of Nannochloropsis oculata and Nitzschia sp. using Soxhletation and Bligh Dyer extraction methods. This research also aims to determine the comparison of lipid yields from the two extraction methods. Lipid yield percentage was determined through gas chromatography analysis. The research results showed that the percentages of FFA, MAG, DAG, and TAG for N. oculata ranged from 3.34 - 33.79% (soxhletation) and 0 - 17.54% (bligh dyer). Meanwhile, for Nitzschia sp., the percentage ranged from 7.16 - 26.28% (soxhletation) and 0.45 - 13.73% (bligh dyer). Lipid yield for N. oculata was 1.81% (soxhletation) and 2.21% (bligh dyer), while for Nitzschia sp., 0.96% (soxhletation) and 2.10% (bligh dyer). Based on the results of both extraction methods, it was found that the total lipid percentage of the microalgae N. oculata was higher than Nitzschia sp.
Total Metabolit Sekunder dan Uji Aktivitas Antioksidan Daun Juwet (Syzygium cumini L.) dengan Spektrofotometer Uv-Vis: Total Secondary Metabolites and Test of Antioxidant Activity of Juwet Leaves (Syzygium cumini L.) with Uv-Vis Spectrophotometer Tien, Tien Wahyu Handayani; Rasmiyanti, Ni Kadek Evy; Tandi, Joni; Magfirah
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16672

Abstract

The aim of this research is to determine the total amount of secondary metabolites (alkaloids, flavonoids, saponins and tannins) contained in the ethanol juice of juwet leaves (Syzygium cumini L.) using the UV-Vis spectrophotometry method and to determine the antioxidant activity of the ethanol juice of juwet leaves based on IC50 value. Determination of total levels of secondary metabolites using UV-Vis spectrophotometry and antioxidant testing using the DPPH method. The results of qualitative analysis of the ethanol juice of juwet leaves contained secondary metabolite compounds, namely flavonoids, saponins, tannins and alkaloids. The average value obtained for the level of total secondary metabolites for flavonoid compounds was 0.417% w/w., saponins 0.766 w/w., tannins 0.282 w/w and alkaloids 0.384% w/w. The results of testing the antioxidant activity of juwet leaf ethanol extract and quercetin as a comparison had antioxidant activity, the average IC50 results were 14.289 ± 0.255 ppm and 102.45 ppm, therefore they were classified as moderate antioxidants.
Determination of Boron Concentration at Sausage Samples with Distillation of Ester Borane Method using Fluorescence Spectrophotometry Lailatusholihah, Isna; Aisyiah Restutiningsih Putri Utami; Micha Mahardika
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16673

Abstract

The study of borax contamination in food samples was successfully analyzed. This study used sausage samples using the Fluorescence Spectrophotometry method. Sausage samples were from Daerah Istimewa Yogyakarta (DIY). This study used 4 sausage samples. The samples were given labels A, B, C, and D. The steps of the research were optimation of distillation time, optimation of catalyst, optimation of solvent, and then followed by analyzing the borax concentration on sausage samples. Based on this study, the optimum distillation time was 24 hours. On the other hand, the best catalysts and solvents were sulphuric acid and ethanol. The A and B samples contained borax contamination and the concentration was under 5 ppm. The C and D samples contained borax contamination and the concentration was above 5 ppm. The conclusions were that A and B samples were not given borax addition and C and D samples were given borax addition.
Penggunaan Arang Aktif Ampas Kopi untuk Menurunkan Bilangan Peroksida dan Asam Lemak Bebas (ALB) pada Minyak Goreng Bekas : Utilization of Activated Charcoal from Coffee Grounds to Reduce Peroxide Number and Free Fatty Acid (FFA) in Used Cooking Oil Prismawiryanti; Andarwati, Sophia; Syamsuddin
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December 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.2023.v9.i3.16845

Abstract

The peroxide value and free fatty acid content influence the quality of cooking oil. Activated charcoal from coffee grounds has been used in processing used cooking oil. This research aimed to determine the ratio of coffee grounds activated charcoal adsorbent-to-used cooking oil (w/v) and the optimum contact time to reduce used cooking oil's peroxide and free fatty acid levels. The ratio of adsorbent and used cooking oil was 1:20, 1:10, and 1:5 (w/v) with contact times of 60, 90, and 120 minutes. Coffee grounds charcoal was activated by ZnCl2. A ratio of adsorbent and cooking oil 1:5 (10 g activated carbon and 50 ml cooking oil) reduced the peroxide number from 12 mek/O2 kg to 9.8 mek/O2 kg and free fatty acids from 0.972% to 0.383%. A contact time of 120 minutes could optimally reduce the peroxide number and free fatty acids from 12 mek O2/kg to 9.3 mek O2/kg and 0.972% to 0.332%, respectively. Coffee grounds have the potential to be processed into activated charcoal for refining used cooking oil.
Tofu Liquid Waste Treatment Using Effective Volume of Anaerobic Sequencing Batch Reactor (ASBR) Budiastuti, Herawati; Rachmawati, Anissa Nurul; Agustin, Delliana; Paramitha, Tifa; Rusdianasari
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 1 (2024): 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.2024.v10.i1.16478

Abstract

The tofu industry produces liquid waste containing high organic compounds. Organic compounds in liquid waste can threaten aquatic ecosystems if discharged directly into water bodies. One of the most effective wastewater treatment systems is the treatment using Anaerobic Sequencing Batch Reactor (ASBR). Besides being able to reduce the content of organic compounds, ASBR can produce biogas, and its decomposing microorganisms do not flow into the effluent stream. The purpose of this study was to evaluate the performance of ASBR at an effective reactor volume according to the design. This is because the use of ASBR in previous studies had not reached the operational stage and did not use an effective volume reactor. The stages of waste treatment using ASBR include the seeding, acclimatization, and operation stages. Waste treatment took place at room temperature in the reactor with an effective volume of 6 L. The operating parameters tested were MLVSS, COD, BOD, pH, and cumulative biogas volume. The results obtained show that the seeding process took 56 days, acclimatization took 10 days, and the operation lasted for 17 days. The efficiency of reducing COD concentration was 60%, the efficiency of reducing BOD concentration was 35.65%, and the cumulative volume of biogas produced was 24,120 mL at the operating stage. The use of the ASBR system at an effective volume of 6 L resulted in the successful processing of tofu liquid waste.
Evaluasi dan Modifikasi Alat Penukar Ion dengan Penambahan Kolom Adsorpsi Karbon Aktif untuk Menurunkan Kesadahan : Evaluation dan Modification of Ion Exchange Equipment with the Addition of Activated Carbon Adsorption Column to Reduce Hardness Endang Kusumawati; Retno Dwi Jayanti; Lestari Herlianti Putri; Nurul Annisa; Paramitha, Tifa
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 1 (2024): 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.2024.v10.i1.16556

Abstract

Ion exchange is one of the water treatment methods used to reduce hardness. To improve the performance of the ion exchange columns, modification can be done by adding an activated carbon column placed after the ion exchange column to adsorb ions that were not exchanged by the resin so that the treated water met boiler feed water quality standards. The purposes of this study were to determine the best flow rate to reduce hardness in the configuration of the ion exchange and activated carbon columns, determine the saturation time of each column, and determine their exchange/adsorption capacities. The steps of this study included modifications and repair of equipment, leak tests, and configuration system performance tests. Performance tests were conducted by varying the feed flow rates by 0.2; 0.4; 0.6; 0.8; 1 GPM and analyzed the efficiency of hardness reduction. The results of this study showed that the best flow rate to reduce the initial hardness of 499 mg/ L CaCO3 was a flow rate of 0.6 GPM or 2.2 LPM. The efficiency of hardness reduction in the configuration system was 100%. The conductivity of the effluent of anion column and activated carbon column decreased compared to the conductivity of the effluent of cation column with an average decrease of 33.17% in the anion column and 18.35% in the activated carbon column. The saturation time of the configuration system was 168 minutes in cation resin, 46.4 minutes in anion resin, and 159 minutes in activated carbon. Furthermore, the adsorption capacity of cation resin, anion resin, and activated carbon were 35.28 mg/g, 43.98 mg/g, and 9.61 mg/g, respectively. The addition of activated carbon in the configuration system lowers the conductivity of the effluent and decreases hardness.
Kinerja Analitik Mikrokapsul Magnetit - Alginat (MNPs-ALG) untuk Analisis Ion Logam Cu(II) dan Aplikasinya pada Sampel Alam: Analytical Performance of Magnetite - Alginate Microcapsules (MNPs-ALG) for Analysis of Cu(II) Metal Ions and Their Application in Samples Lianasari, Ika Yekti; Aman Sentosa Panggabean; Bohari Yusuf; Alimuddin; Koesnarpadi, Soerja
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 1 (2024): 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.2024.v10.i1.16574

Abstract

Research has been carried out regarding the synthesis of Magnetite-Alginate microcapsules (MNPs-ALG) and applied to Cu (II) metal ions. The nature of magnetic nanoparticles, Fe3O4 which easily form aggregations can be overcome by this encapsulation process, but a very efficient separation process is also very much needed in the analytical separation process.The process of making magnetite nanoparticle compounds is carried out first using FeCl2.4H2O and FeCl3.6H2O and adding concentrated ammonia at a temperature of 90οC until the solution becomes blackish in color. The dry magnetite, Fe3O4, nanoparticles were then dissolved in distilled water and thickened with Na-Alginate then dropped slowly into a 1 M CaCl2 solution. The results of characterization using SEM showed that there were differences in morphology before and after contact, and there was 0.98% mass of Cu elements on the EDS results.The microcapsule adsorption optimization test gave results for the best adsorption percentage >90% on a mass variation of magnetite (MNPs) of 0.3 grams; pH 5; contact time of 30 minutes and retention capacity of 185.95 mg/gram, at a Cu(II) concentration of 800 ppm. Analytical performance shows the best results with linearity parameters with a correlation coefficient of 0.999; the detection limit and quantitation limit are 0.0516 ppb and 0.1720 ppb with a lifetime of four times. The application of samples in the form of river water samples shows a percent recovery value of around >90%, indicating that there is no matrix that significantly influences the measurements.

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