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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 325 Documents
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Efektivitas Fotodegradasi Lignin dari Limbah Ampas Sagu (Metroxylon sagu Rottb.) Menggunakan Katalis TiO₂: The Effectiveness of the Photodegradation of Lignin from Sago (Metroxylon sagu Rottb.) Waste Using TiO₂ Catalyst Muh. Natsir; Aden Mula Pratiwi; Thamrin Azis; Nohong; Imran; Wa Ode Harlis; Alimin; La Ode Kadidae; Ruslan; C Bijang; La Ode Abd Kadir; Laily Nurliana
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 3 (2022): 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.2022.v8.i3.16149

Abstract

Lignin degradation from sago (Metroxylon sagu Rottb.) waste has been carried out using a TiO2 catalyst. This research aims to determine the effectiveness of lignin degradation from sago waste using a TiO2 catalyst. Lignin from sago pulp was isolated using 10% NaOH and characterized using Fourier Transform Infra Red (FTIR) spectroscopy. The results of the characterization using FTIR show that the absorption at wave number 2937.59 cm-1 is the -C-H stretching vibration of the alkane functional groups, the absorption at wave number 2360.87 cm-1 is the vibration of the C≡C triple bond, the wave numbers 1795.73 cm-1 and 1637.56 cm-1 are associated with the stretching of the carbonyl group. The absorption at wave number 1427.32 cm-1 is a C-H vibration connected to an unsaturated bond in an aromatic ring. Absorptions at wave number 1105.21 cm-1, 1128.36 cm-1, 1153.43 cm-1 were the stretching vibration of -C-H on the guaiasil ring, and the absorption at wave number 1022.27 cm-1 was the stretching vibration of C-O-C ether. From this spectrum, it can be seen that lignin is not completely pure because it is probably still mixed with cellulose. The results of the effectiveness test of lignin degradation using a TiO2 catalyst with the help of UV light were able to degrade the lignin isolated by 31.43%, for 3 hours at a lignin concentration of 40 ppm.
Ekstraksi Teh Hijau dan Aplikasinya sebagai Pengendali Korosi Pada Pompa di Lingkungan Garam NaCl 3,56%: Green Tea Extraction and Its Application as Corrosion Controller in 3.56% NaCl Retno Indarti
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 3 (2022): 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.2022.v8.i3.16160

Abstract

Green tea leaves contain antioxidant compounds that can be used as organic inhibitors in a corrosion process. Tea leaves were extracted by maceration method using 70% ethanol solution with a solid:solvent ratio of 1:8 (w/v) for 1 x 24 hours in an atmospheric room. The extract was then concentrated with a rotary evaporator and separated with solvent under vacuum conditions at 852 mbar, temperature of 70oC and rotation of 80 rpm. The results of the qualitative test of extra tea leaves using 10% NaOH and 1% FeCl3 changed the color to brownish orange and blue-black. This indicates the content of flavonoids and tannins. Green tea leaf extract is also applied to control the corrosion rate of brass metal. Variations in the concentration of tea leaves were 200, 400, 600 ppm in 3.56% NaCl solution. The pump circulation is carried out for 40 hours, the weight loss method is carried out every 8 hours. The average corrosion rate without inhibitor is 3.95 mmpy, the corrosion rate with 200 ppm inhibitor is 1.24 mmpy, the corrosion rate with 400 ppm inhibitor is 0.46 mmpy, the corrosion rate with 600 ppm inhibitor is 0.23 mmpy. A significant decrease in the corrosion rate occurred at a concentration of 600 ppm with an efficiency of 92.32%.
Evaluasi Kadar Senyawa Fenolat, Flavonoid Total, serta Aktivitas Antioksidan Secara in vitro dalam Ekstrak Metanol Bawang Dayak (Eleutherine palmifolia (L.) Merr : Evaluation of Phenolic Compounds, Total Flavonoid Content and in vitro Antioxidant Activity of Methanol Extract of Dayak Onion Bulbs (Eleutherine palmifolia (L.) Merr Farida Laila; Ika Resmeliana; Wina Yulianti; Atep Dian Supardan
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 3 (2022): 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.2022.v8.i3.16175

Abstract

Dayak onion bulbs are a plant originating from Kalimantan which has been used for generations to treat various diseases. This plant is quite easy to grow and develop in many places in Indonesia. The aims of the present study were to evaluate the antioxidant potential of the methanol extract of Dayak onion bulbs based on the total of the phenolic and flavonoids contents and also the antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability, ferric reducing power and total antioxidant capacity. The results showed the total phenolic and flavonoid methanol extract of Dayak onion bulbs were 14.49 ± 1.42 mg GAE/g dry weight and 5.41 ± 1.01 mg QE/g dry weight, respectively. Antioxidant activity as measured by the DPPH, total antioxidant capacity, and ferric reduction assay with IC50 values of 16.95 ± 1.58 μg/mL, 24.22 ± 2.51 µg/mL, and 85.40 ± 16.88 µg/mL, respectively. These results suggest that the methanol extract of Dayak onion bulbs has potential bioactive compounds with good antioxidant activity and can be developed as an effective and safe source of natural compounds for functional food or herbal medicine.
Pengaruh Penambahan Variasi KJ-CTAB Terhadap Karakteristik ZnO/KJ-CTAB yang Disintesis Menggunakan Metode Impregnasi Basah: Effect of Adding KJ-CTAB Variations Towards Characteristics of Synthesized ZnO/KJ-CTAB Using Wet Impregation Method Alviana, Azzalina Nur; Rosanti, Aulia Dewi; Shobirin, Rizky Arief; Hidayat, Fahmi
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16036

Abstract

Semiconductor photocatalysts have great potential in solving environmental problems. The photocatalyst process using a semiconductor is one of the technology to oxidize organic compounds such as dyes. Orange peel (KJ) is one of the adsorbents that have the potential for purification of dyes that increase the photocatalytic activity of ZnO material. This study aims to determine the optimum variation of KJ-CTAB to be added to ZnO material. The results of the synthesis of ZnO/KJ-CTAB varasis 1:25, 2:25, and 3:25 (w/v) using the wet impregnation method were characterized on IR, XRD, SEM, DR-UV, and BET instruments. The results showed that FTIR also showed the presence of ZnO bonds in all samples, C-H in samples varied from 1:25, 2:25, and 3:25 (w/v). The XRD results showed that the percentage of crystallinity decreased and the SEM results showed that ZnO/KJ-CTAB 1:25 had a more homogeneous morphology. Based on the results of DR-UV ZnO/KJ-CTAB 1: 25 (w/v) has a band gap energy value of 3.20 eV which is good for use in photocatalyst processes. BET results show that all samples belong to the mesoporous size.
Sintesis dan Karakterisasi Cangkang Kapsul Non Gelatin dari Rumput Laut (Eucheumma cottonii) dan Kaktus Koboi (Cereus peruvianus) untuk Sistem Penghantaran Obat: Synthesis and Characterization of Non Gelatinized Capsule Shells from Seaweed (Eucheumma cottonii) and Koboi Cactus (Cereus peruvianus) for Drug Delivery Systems Mahardika, Micha; Susparini, Ninik Triayu; Dewaldo, Dany; Situmeang, Boima; Amin, Fauzan
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16098

Abstract

Research on drug delivery systems continues to develop, including making the latest formulations on capsule shells as a medium for drug delivery. The effort that has been done was developing non-gelatine drug delivery materials made from the combination of seaweed and cactus. The main component in making gel on seaweed and cactus is the polysaccharide pectin. This study aims to make and determine the characterization of capsule shells from a combination of seaweed and cactus. Capsule shells are made from a combination of pectin extracts from seaweed and cactus with 5 different ratios of 0:4 (A), 1:3 (B), 2:2 (C), 3:1 (D), and 4:0 (E). The characterization involved weight uniformity test, disintegration time test, water swelling test, and dissolution test. Pectin from green seaweed and koboi cactus weighed 235 g and 75 g. The capsule shell weights based on Farmakope Indonesia sixth edition were 307.2, 311.6, 309.7, 304.6, and 308.7 mg. The capsule shell disintegration times, based on Farmakope Indonesia sixth edition, 2020, were 15,16, 14, 21, and 12 minutes, and the best result of the water swelling test was C capsule (2:2) of 666.7%. The results of the capsule shell dissolution test showed that the reduction of the capsule shells did not exceed 10% for 30 minutes according to the Farmakope Indonesia sixth edition. The capsule shells made from a combination of seaweed and cactus can be used as material in drug delivery systems. Non-gelatinized capsule shell which is expected to have anti-inflammatory activity.
Perbandingan Metode Maserasi dan Microwave-Assisted Extraction pada Daun Beluntas dengan Variasi Pelarut dan Uji Antioksidan: Comparison of Maceration and Microwave-Assisted Extraction on Beluntas Leaves with Variation of Solvent and Antioxidant Test Utomo, Yudhi; Chairini, Nur; Asrori, Muhammad Roy
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16155

Abstract

Beluntas leaves (Pluchea indica L.) as Indonesian herbal plants contain secondary metabolites such as flavonoids. Beluntas leaf parts can be used as medicine. The content of secondary metabolites in Beluntas leaves acts as a natural antioxidant. Beluntas leaf extraction has not been optimal so far. Microwave assisted extraction can increase the yield. This research aims to study the effect of giving different types of solvents of extraction on Beluntas leaves on the levels of flavonoids and the resulting antioxidant activity, and determine the profile of Beluntas leaf extraction results based on comparative trials of the maceration method and MAE (microwave-assisted extraction). This research was conducted in 4 stages: (1) sample preparation of dried Beluntas leaves, (2) extraction by maceration with various types of solvents n-hexane, ethyl acetate, and 70% ethanol, (3) the characteristics of the flavonoid compounds, namely the qualitative test and the quantitative test with AlCl3, and (4) the measurement of antioxidant activity in Beluntas leaf extract using the DPPH method. The results of this study obtained a total flavonoid content of 4.23 mgQE/g which was the result of maceration of the ethyl acetate solvent extract (yield: 5.09%), and all Beluntas leaf extracts in ethyl acetate solvent were included in the category of very strong antioxidant activity with an IC50 value of 31.68 μg/mL.
Analisis Kadar Kurkumin pada Herbal Oil Kunyit Ekstrak Virgin Coconut Oil dengan Metode Ultrasonik dan Maserasi: Analysis of Curcumin Levels in Turmeric Herbal Oil Extract Virgin Coconut Oil with Ultrasonic and Maceration Methods Mahmudah, Rif'atul; Nada, Ufilia Quthrotun; Aulia, Sakinatul
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16178

Abstract

Vegetable oil theoretically and experimentally has proven its potential as an alternative solvent in the extraction of natural materials. Turmeric infused with virgin coconut oil (VCO) is a way to take advantage of the active compounds from the herbs and the oil itself. This study aims to determine the ability of the VCO solvent in extracting curcumin compounds from turmeric with the addition of tween 80 surfactants. The extraction method used was maceration at 60℃ and an ultrasonic frequency of 40 kHz for 15 minutes. Thin layer chromatography (TLC) was used for qualitative analysis of each herbal oil extract using chloroform: methanol (95:5) eluent and FTIR spectrophotometer to identify functional groups. The highest curcumin content was found in herbal oil with tween 80 of 2 ml, namely 31 ppm in maceration extraction and 260.7 ppm in ultrasonic extraction. Identification of curcumin functional groups in herbal oils showed absorption patterns of O-H, C=O, aromatic C=C, C-O-C, and C-H.
Penggunaan Sabut Kelapa Teraktivasi NaOH sebagai Adsorben Metilen Biru: Utilization of Coconut Fiber NaOH-Activated as Blue Methylene Adsorbent Baunsele, Anselmus Boy; Boelan, Erly Grizca; Kopon, Aloisius Masan; Taek, Maximus M.; Tukan, Gerardus D.; Missa, Hildegardis
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16274

Abstract

Methylene blue is a textile dye with carcinogenic and mutagenic properties which can cause various problems for the environment and organisms, therefore it is necessary to treat the waste. This study describes the adsorption of methylene blue using base-activated coconut coir. Coconut coir as waste was prepared into 80 mesh-sized powder and then activated using NaOH solution. The base-activated coconut fiber was then used for methylene blue adsorption under several optimization conditions such as pH, contact time, concentration, and adsorption isotherm. The determination of methylene blue was adsorbed by the adsorbent measured using UV-VIS. The pH and contact time results were 7 and 75 minutes, respectively, with the adsorption capacity (qe) of 1.98 mg g-1 and 99.91%. The isotherm adsorption of blue methylene followed the Langmuir isotherm model with the maximum adsorption capacity (Qmax) of 0.2 mg -1. The result showed that the coconut fiber base activated could be used as a dye adsorbent.
Sintesis dan Karakterisasi Semikonduktor TiO2 Doping Magnesium dengan Metode Hidrotermal: Synthesis and Characterization of Magnesium Doped TiO2 Semiconductor by Hydrothermal Method Paramitha, Tika; Utami, Khoirunnisa; Anggraini, Yuki Martha; Paramitha, Tifa
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16275

Abstract

Semiconductors are materials that range between insulators and conductors in terms of conductivity value. Titanium Dioxide (TiO2) is a semiconductor that is widely applied to various things. TiO2 has the benefits, such as being environmentally stable and inexpensive. TiO2 is photoactive in the range of ultraviolet radiation due to the band gap value of 3.2 eV. However, ultraviolet is only produced from 5% of sunlight. The research aimed to narrow the band gap energy so as to maximize light absorption. This is done by modification with the addition of Mg elements to TiO2 materials at different mass variations of Mg (1%, 1.5%, 2%) to the mass of TiO2 which is often referred to as doping. TiO2 was doped by Mg using a hydrothermal method for 24 hours with a temperature of 180áµ’C, followed by 2 hours of calcination at 400áµ’C. Then, TiO2 and Mg-doped TiO2 particles were characterized by SEM-EDX, FTIR, and UV-Vis. Based on the results of TiO2 and Mg-doped TiO2 particle characterization using SEM, both particles are spherical in shape. The success of Mg doping was identified from the data of EDX characterization, which revealed that the mass % of the Mg component increased with the greater Mg doping concentration on TiO2 particles. There was no structural change following Mg doping on TiO2 particles, as evidenced by the same peak based on the results of FTIR characterization of TiO2 and Mg-doped TiO2 particles. Moreover, a 2% Mg mass doping on pure TiO2 resulted in a decrease in band gap energy to 3.16 eV, in which the pure TiO2 was 3.39 eV. The mass doping of Mg on TiO2 required further optimization to obtain the maximum band gap energy reduction for photocatalytic applications.
Aktivitas Antioksidan, Kadar Flavonoid, dan Fenolik Total Cangkang Kerang Mutiara (Pinctada maxima): Antioxidant Activity, Flavonoid Content, and Total Phenolics of Pearl (Pinctada maxima) Clam Shells Ngibad, Khoirul; Muadifah, Afidatul; Sukmawati, Datin An Nisa
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 1 (2023): 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.2023.v9.i1.16281

Abstract

Antioxidant compounds are able to dampen or ward off free radicals. Living things including pearl mussels (Pinctada maxima) can produce secondary metabolite compounds (phenolics, alkaloids, and terpenoids). There have been no studies on the antioxidant potential, flavonoid content, and total phenolics of pearl clam shells. This study aimed to determine the antioxidant potential of pearl clam shell ethanol extract (EECKM) in vitro using the DPPH method. In addition, it aims to determine the total flavonoid and phenolic levels of EECKM. The powder of pearl mussel shells is soaked with ethanol and the filtrate is concentrated until a concentrated extract is obtained. Flavonoid and phenolic levels from EECKM were measured using a UV-Vis spectrophotometer. Measurement of antioxidant activity using the DPPH method. EECKM has a yield of 1.73%, flavonoid levels of 0 mg QE/g, and total phenolics of 4.8 mg GAE/g. The extract has the highest antioxidant activity for a concentration of 100 mg / L with a percent value of DPPH radical inhibition of 67.1%.

Page 26 of 33 | Total Record : 325

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