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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 11 Documents
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Search results for , issue "Vol. 10 No. 2 (2024): August Edition" : 11 Documents clear
Optimalisasi Limbah Serbuk Gergaji Kayu Jati (Tectona grandis L.f) Sebagai Adsorben Logam Berat Kobalt (Co) dengan Metode Aktivasi Kimia: Optimization of Teak Wood Sawdust Waste (Tectona grandis L.f) as Heavy Metal Adsorbent of Cobalt (Co) by Chemical Activation Method Faradin, Faradin; Muharti, Asti; Dinafa, Nazwa Jinanti; Widiyanto, Holisha
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.16629

Abstract

Teak wood (Tectona grandis L.f.), a high-quality wood commonly used in Indonesia, specifically in the Cilegon area, has the potential to be used as an alternative to reduce environmental pollution. This research aimed to test teak wood sawdust waste as an adsorbent for cobalt heavy metal, create activated charcoal from the sawdust waste for the same purpose, and determine the optimal conditions for treatment with and without chemical activation. Industrial waste samples were found to contain 50.7 ppm of cobalt metal through ICPS testing. Activated chemical adsorption, without activation and with industrial wastewater mixture, resulted in a decrease in cobalt metal concentration by 78.2% or 11.08 ppm. The optimal conditions for activated chemical adsorption were found at a pH of 5, an adsorbent mass of 600 mg, and a time of 40 minutes, resulting in decreases of 60.9% (21.2751 ppm), 71% (15.7821 ppm) and 67.7% (17.5812 ppm), respectively. The results show that teak wood sawdust waste can effectively adsorb cobalt heavy metal, providing a potential solution for industrial wastewater treatment.
Evaluation of Counter Current Horizontal Screw Extractor’s Performance in Determining Leaching Equilibrium of Clitoria ternatea Anthocyanins Ramadhani, Laily Isna; Hidayatulloh, Irwan; Nurcahyo; Trirahayu, Dhyna Analyes
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17005

Abstract

Anthocyanin compounds as natural coloring substances contained in Clitoria ternatea flowers have higher antioxidant activity than anthocyanins from other flower extracts. Obtaining anthocyanin extract from Clitoria ternatea flower can be done using the solid-liquid extraction method. The objectives of this study include making a leaching equilibrium diagram of Clitoria ternatea flowers and determining the optimum L/S ratio and the number of equilibrium stages in the counter current horizontal screw extractor. In the maceration process, a leaching equilibrium diagram is produced, which is then used to design and determine the number of equilibrium stages. The equilibrium diagram of anthocyanins from Clitoria ternatea flowers with a gradient slope to the right is in accordance with the literature so that the equilibrium diagram can be used in the design of the extraction unit and the calculation of the theoretical stage of the multi-stage extraction unit. Based on the equilibrium diagram, the Number of Transfer Units (NTU) of 4 stages and the Height of the Transfer Unit value of this process is 0.105 m.
Sintesis dan Karakterisasi Zeolit X dari Fly Ash Batu Bara Menggunakan Metode Sintesis pada Suhu Rendah: Synthesis and Characterization of Zeolite X From Fly Ash Waste Using Synthesis Method at Low Temperature Rieswana, Yuried; Aisyah, Aurela Naura; Sani; Suprihatin
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17028

Abstract

Many industries in Indonesia have switched to using coal fuel. The use of coal at PT PLTU Paiton has reached 250 tons per hour and produces 4% of waste by-products of combustion contained from bottom ash by 25% and fly ash by 75%. Fly ash waste will harm the environment and health. Fly ash contains many components, including SiO2 52%, Al2O3 31.86%, Fe2O2 4.89%, CaO 2.68%, and MgO 4.66%. This research aims to synthesize and characterize zeolite X from PT Paiton fly ash using a low-temperature synthesis method. Zeolite X synthesis in this study has 3 steps: The pretreatment process, silica synthesis process, and zeolite synthesis process. The results of silica synthesis obtained SiO2 55.54%. The resulting zeolite product has a typical peak at 2Ï´ 28.72. Zeolite x has a wavelength of 430, 570, 695,7, and 965,7, which respectively indicates Si-O-Si and Si-O-Al bonds, double ring bonds, T-O ring symmetric strain (internal), and asymmetric (internal). The results of zeolite X crystal synthesis in this study could not be formed in the variable of adding time of 3-5 hours with a variation of moles of Al2O3 0,5-1,5 moles.
Modifikasi Biofoam Berbasis Pati Singkong dengan Serat Eceng Gondok dan Variasi Konsentrasi Plasticizer: Modification of Cassava Starch-Based Biofoam with Water Hyacinth Fiber and Concentration Variation of Plasticizer Hutagalung, Sarawinda; Sibarani, James; Pramesti , Resia Yoan; Puspaningtya, Theresia Hellen Renata
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17104

Abstract

Biofoam is a plant-based alternative packaging. The biofoam was prepared by using the extrusion method and baking process. This research aims to determine the lowest ratio of PVA and glycerol in absorbing water and testing the mechanical properties of biofoam (tensile strength, biodegradation test and FTIR analysis. The best biofoam composition in absorbing water was obtained at a ratio of PVA: glycerol 8%. The results of biofoam characteristics obtained by the water absorption test were 9.76%, maximum bending strength was 9.20 MPa and biofoam can be degraded 100% on day 15. The results of FTIR analysis showed the presence of absorption spectra at wave numbers 3410,15 cm-1, which is a typical region of O-H functional groups (strong and broad) carbohydrates and polyphenols. Modification of starch with fiber and plasticizer in research improves the physicochemical characteristics of biofoam in terms of increasing water absorption and biofoam biodegradation. In contrast, in terms of mechanical properties, the bending strength of biofoam requires further research referring to the characteristics of biofoam mechanical properties toward SNI standards.
Pemanfaatan Limbah Karbon-Aktif Melalui Reaktivitasi Termal Sebagai Adsorben Ion Kadmiun pada Lindi TPA: Utilization of Activated Carbon Waste Through Thermal Reactivity as a Cadmium Ion Adsorbent in Landfill Leachate Sardi, Bambang; Afrilya, Anggie Putry; Andriani, Sitti Maghfirah; Novika, Try; Azzahra, Fadlia; Hidayat, Wahyu
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17169

Abstract

The leachate produced at the Kawatuna landfill, managed without proper waste treatment systems, has been found to contain heavy metals like cadmium (Cd), which contaminate groundwater and pose significant health risks. This study investigates the reduction of Cd ions in leachate through adsorption using activated carbon (AC) waste. The AC waste was reactivated via thermal methods, including phosphoric acid immersion, heating, and washing. Morphological analysis was conducted using scanning electron microscopy (SEM), and adsorption efficacy was evaluated with atomic absorption spectroscopy (AAS). The findings indicate that AC waste with a pore diameter of 2.95 µm can be effectively reused as an adsorbent through thermal reactivation. Specifically, AC treated with H3PO4 immersion and heating exhibited a pore diameter of 3.24 µm, while heating and washing resulted in a pore diameter of 2.29 µm. The Cd concentration in leachate treated with AC immersed in H3PO4 followed by heating showed a modest reduction, whereas the heating and washing treatment led to a significant decrease in Cd levels, achieving an adsorption capacity of 3.92 mg/L within 50 min. This method presents a viable alternative for managing landfill leachate at the Kawatuna site.
Biosintesis Nanopartikel ZnO dengan Ekstrak Temu Kunci (Boesenbergia rotunda) Dibantu Gelombang Mikro, Serta Pengujian Aktivitasnya Terhadap Bakteri : Biosynthesis of ZnO Nanoparticles Using Fingerroot (Boesenbergia rotunda) Extract Assisted by Microwave and Evaluation of Their Antibacterial Activity Junaedi, Yusup; Sugita, Purwantinigsih; Farid, Muhamad
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17229

Abstract

Numerous ZnO nanoparticles have been successfully synthesized using diverse plant extracts, yet research utilizing B. rotunda extract as a capping agent with microwave assistance has been lacking. Hence, this study aimed to employ microwave-assisted B. rotunda extract to produce ZnO nanoparticles and test their antibacterial activity. By utilizing 10 mL of 1% (m/v) B. rotunda extract at pH 12.5 and calcinating for 3.8 hours at 200°C, coupled with 20 minutes of microwave treatment, ZnO nanoparticles averaging 78.78 nm in diameter were synthesized. Particle size was determined using the ImageJ software to analyze TEM images. UV-Vis absorption spectroscopy indicated a peak wavelength at 360 nm, while FTIR analysis identified compounds from B. rotunda extract crucial in nanoparticle formation. Antibacterial testing revealed the nanoparticles' ability to create an inhibition zone against E. coli growth.
Spesiasi dan Bioavailabilitas Merkuri dalam Sedimen Teluk Palu Pasca Gempa dan Tsunami dengan Metode Diffusive Gradient in Thin Film (DGT): Speciation and Bioavailability of Mercury in Palu Bay Sediments Post Earthquake and Tsunami Using the Diffusive Gradient in Thin Film (DGT) Method Sosidi, Husain; Khairuddin; Dwiyana, Putri; Ruslan, Ruslan
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17264

Abstract

Speciation and bioavailability of mercury in the sediments of Palu Bay after the earthquake and tsunami were conducted using fractionation and Diffusion Gradient in Thin Films (DGT). This method has been conducted using sediment samples from the estuary of the Pondo River, Palu. Heavy metal speciation of mercury ions was conducted by looking at the distribution of mercury ions in various species by sequential extraction and heavy metal bioavailability of mercury ions. This method was conducted by looking at the migration of mercury ions from sediments into the seawaters using a Diffusive Gradient in Thin Films (DGT). The speciation of mercury ions concentration with sequential extraction as EFLE (easily, freely, leachable, exchangeable) fraction is about < 0.0005 ppm, the oxidizable fraction is about < 0.0005 ppm and the resistant fraction is between < 0.0005 ppm to 0.0063 ppm. The results of DGT experiments to study the migration of mercury ions from sediments into the seawaters during 3 days of immersion is between 0.01003 ppm and 0.01748 ppm. The availability of mercury ions concentration in the sediments allows for the migration of mercury ions into water.
Pengaruh Ukuran Partikel dan Suhu Terhadap Derajat Asetilasi dan Yield Pada Ekstraksi Kitin dari Belalang Melalui Green Method: The Effect of Particle Size and Temperature on the Degree of Acetylation and Yield in Chitin Extraction from Grasshoppers Using the Green Method Savitri, Meila; Pangestoe, Safina Handayani; Hilman Imadul Umam; Meka Saima Perdani; Teguh Pambudi
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17268

Abstract

Grasshoppers are insects that are pests for agriculture. In recent years, humans have begun to realize the broader economic value of insects, which are not only used as animal feed but also as sustainable biopolymers, such as chitin and chitosan. Grasshoppers' body organs contain chitin, including the digestive tract (intestine), trachea system, and exoskeleton (outer skeleton). Currently, the chitin extraction process using the green method with Deep Eutectic Solvent (DES) is more popular because it reduces the use of dangerous chemicals, reduces waste, and is overall more environmentally friendly than using chemical and biological methods. In the chitin extraction process, process parameters, such as reaction time, temperature, and particle size of the raw material, are adjusted to obtain the desired properties of chitin. This research aims to determine the effect of particle size and temperature on chitin yield and degree of acetylation (DA). The research results show that the yield values ​​and DA values ​​produced in this research are not by similar references which have described the characteristics of chitin. However, there is one sample showing that the most optimal DA value is the BSC 7 150 mesh 90°C sample, at wavelengths of 1560 cm-1 and 2875 cm-1, producing a DA value of 55.79514% and DD 44.20485933%. The best yield value was BSC 2 110°C 50 mesh, with a value of 22.1%.
Adsorpsi Logam Cu(II) dengan Hidrogel CMC/Pektin Komposisi 2:1 Menggunakan Metode Freeze-Thaw: Adsorption of Cu(II) Metal by Hydrogel CMC/Pectin Composition of 2:1 Using The Freeze-Thaw Method Maelan, Nabila Maharani; Nurazizah Melani Dewi; Sri Andini; Meka Saima Perdani; Aulia Wahyuningtyas
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17273

Abstract

The Citarum River is included in the category of the most polluted river in the world because it contains chemicals that can reduce air quality. This pollution not only affects air quality but also threatens public health and the surrounding ecosystem. Heavy metals, especially Cu(II), are one of the contaminants that have exceeded the threshold and can cause serious health impacts, including organ damage and nervous system disorders. Hydrogel is an alternative adsorbent that is widely used in various fields, especially in the field of air purification. Hydrogel has the ability to absorb and adsorb contaminants. In particular, Carboxymethyl Cellulose (CMC) hydrogel and pectin hydrogel have attracted much attention for safe water purification because they are non-toxic and have good biodegradability and biocompatibility. The researchers conducted a study on the adsorption of Cu(II) metal using a Carboxymethyl Cellulose (CMC) hydrogel adsorbent and pectin in a 2:1 composition through the Freeze-thaw method. FTIR analysis of the CMC/pectin hydrogel confirmed the presence of C-O-, O-H, C=O, C-H, OH bending, and COOH stretching vibrations. Based on BET analysis, the hydrogel has micropores, a type 1 isotherm, and a surface area of ​​1,889 m2/g. The Langmuir isotherm model was used to determine the ideal adsorption conditions to be a concentration of 298 ppm, an adsorption capacity of 1,0918 mg/g, and an adsorption efficiency of 13,485%.
Uji Aktivitas Antioksidan dan Kandungan Fitokimia Daun Benalu (Loranthus ferrugineus Roxb.) yang Tumbuh pada Ketinggian Tempat dan Inang Berbeda : Activity Antioxidant Test and Phytochemical Content of Mistletoe Leaves (Loranthus ferrugineus Roxb.) Growing at Different Altitudes and Host Types Iwit, Seswita; Ardi; Syarif, Auzar
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 2 (2024): August 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.i2.17288

Abstract

Restrictions on synthetic antioxidants in several countries have caused the global community to switch to using natural antioxidants. One source of natural antioxidants is mistletoe leaves (Loranthus ferrugineus Roxb.).The presence of mistletoe in a place and host is an important aspect to pay attention to to get the best antioxidants. This research aims to determine the effect of different altitudes and host types on the antioxidant activity and phytochemical content of mistletoe leaves. This research was structured in a split-plot design with 2 factors, namely altitude (lowland and medium land) and host types (avocado, lime, cocoa, and dogfruit). Antioxidant activity test using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method and phytochemical screening using reagents. Variables observed included extract yield percentage, antioxidant activity (IC50 value), and phytochemical screening. The results showed that altitude and host type significantly affected the antioxidant activity of mistletoe leaves. Mistletoe leaves in avocado hosts in the lowlands and medium land showed the best antioxidant activity, namely 155,94 µg/mL and 156,25 µg/mL in the weak antioxidant category, and the highest phytochemical content, namely flavonoids, alkaloids, tannins, saponins, and steroids.

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