cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
Jaya Hardi
Contact Email
jr.hardi0803@gmail.com
Phone
+6281341314717
Journal Mail Official
kovalen.journal@gmail.com
Editorial Address
Program Studi Kimia Fakultas MIPA, Uniiversitas Tadulako Jl. Soekarno-Hatta Km. 9, Tondo Palu, 94117
Location
Kota palu,
Sulawesi tengah
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 8 Documents
 1 
Search results for , issue "Vol. 7 No. 2 (2021): Edisi Agustus" : 8 Documents clear
Kualitas Minyak Ikan Lele Dumbo (Clarias gariepinus) Selama Penyimpanan dengan Penambahan Likopen Kasar dari Buah Tomat: Quality of Dumbo Catfish Oil (Clarias gariepinus) During Storage with The Additing of Crude Lycopene from Tomatoes Heince Andre Pua; Nurhaeni; Erwin Abdul Rahim; Prismawiryanti
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.13905

Abstract

The quality of Dumbo Catfish (Clarias gariepinus) oil can be maintained during storage with the addition of crude lycopene in tomatoes as an antioxidant. The purpose of this study was to obtain the best ratio between crude lycopene in tomatoes and Dumbo catfish oil during storage. The study was conducted using a variable ratio of crude lycopene: Dumbo catfish oil with 4 treatment levels (6:40, 8:40, 10:40, and 12:40 (w/v)) and storage time variables of 1, 2, 3, and 4 weeks. Lycopene levels in Dumbo catfish oil were analyzed using a UV-Vis spectrophotometer, while the quality of Dumbo catfish oil during storage was determined through peroxide value analysis. The results showed that the best ratio of crude lycopene of tomatoes: Dumbo catfish oil was 12:40 at the third week of storage with lycopene content of 0.257 grams and the peroxide value of Dumbo catfish oil was 3.45 meq/kg or had met IFOS standards. Keywords: Crude lycopene, tomato fruit, dumbo catfish oil, peroxide value.
Adsorbsi Ion Logam Cu (II) Menggunakan Biomassa Daun Genjer (Limnocharis flava): Adsorption of Cu (II) Ions by Biomass of Genjer Leaves (Limnocharis flava) Helni Febriani; Dwi Juli Puspitasari; Ruslan; Husain Sosidi
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.14009

Abstract

The adsorption of Cu (II) ions by Genjer (Limnocharis flava) biomass has been carried out. This research aims to determine the optimum pH of the plant and the contact time between the metal ion Cu (II) with the plant that produces the highest absorption, as well as knowing the best adsorbent mass for absorption between Cu (II) metal ions and genjer plants. The study used a completely randomized design (CRD) with variables of pH, contact time, and adsorbent mass. The testing of the absorption of the Genjer leaves biomass against Cu (II) was carried out with Atomic Adsorption Spectrophotometric (AAS). The results showed that the optimum absorption produced was 83.34% at pH 4, and 91.54% with the highest contact time of 30 minutes, and 82.04% with an adsorbent mass of 1 gram. Keywords: Limnocharis flava, pH, contact time, adsorbent mass, adsorption, Cu (II) ion
Pemanfaatan Selulosa dari Rumput Gajah (Pennisetum purpureum) pada Sintesis Karboksimetil Selulosa (CMC) : [Utilization of Cellulose from Pennisetum purpureum at The Synthesis of Carboxy Methyl Cellulose (CMC) Erwin Abdul Rahim; Grace Sita Turumi; Syaiful Bahri; Jusman; Syamsuddin
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.14227

Abstract

Cellulose from Pennisetum purpureum has been used as the main ingredient in the synthesis of carboxymethyl cellulose (CMC). The purpose of CMC synthesis from the cellulose of Pennisetum purpureum is to obtain CMC compounds with the best degree of substitution (DS) value and the highest yield. The study was conducted using a completely randomized design with a factorial pattern consisting of two independent variables, namely the concentration of trichloroacetic acid (10%, 20%, and 30%) and reaction time (3 and 4 hours). The results showed that the CMC with the highest DS value (0.839) was obtained using 20% trichloroacetic acid with a reaction time of 3 hours. The highest CMC yield was 30.15% which was obtained using 30% trichloroacetic acid with a reaction time of 4 hours. Keywords: Pennisetum purpureum, carboxymethyl cellulose, substitution degree.
Pengaruh Asam Itakonat terhadap Properti Polimer Perekat Akrilik Berbasis Air: Effect of Itaconic Acid on the Properties of Acrylic Water Base Adhesive Polymer Rony Pasonang Sihombing; Agustinus Ngatin
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.15507

Abstract

Acrylic-based polymer adhesive is a type of adhesive that can be used for pressure sensitive adhesive (PSA). Itaconic acid (IA) is a type of acid with 2 (two) OH groups which can form hydrogen bonds. The acrylic base can be used purely from its class. In some cases, however, the acrylic base can be used together with another base. Therefore acrylic-based adhesive with variable addition of itaconic acid was introduced in this study. In this application, the holding power property is one of the important parameters of a PSA. Therefore, holding power is the main parameter in this study. This research includes the preparation of tools and materials, mixing the main raw materials of acrylic monomer and itaconic acid with the types of surfactants and water, and product characterization. The polymerization process is carried out at a pressure of 1 atm with a temperature of 75°C - 80°C accompanied by stirring with a rotation rate of ± 500 rpm. The characterization of this research resulted in a PSA product with a holding power of 2 kg for 30 seconds to 620 minutes. While the resulting peel strength is 1.12 kgf / inc to 0.76 kgf / inc. Keywords: itaconic acid, acrylic PSA, holding power
Pemanfaatan Lumpur Minyak dengan Solar sebagai Energi Alternatif Bahan Bakar: Utilization of Oil Sludge with Diesel as Fuel Alternative Yunus Tonapa Sarungu; Rony Pasonang Sihombing
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.15509

Abstract

Oil sludge resulting from crude oil processing in the petroleum industry could have a negative impact on the environment. Oil sludge could also be classified as hazardous waste and able to damage the environment and human health. Therefore, it was necessary to solve this issues. Oil sludge hydrocarbon utilizing to get higher value was one of solution offered by these research. In the utilization process, filtration method was used at first procedure and followed by diesel mixing at ratio 1:0.1, 1:0.2, 1:0.3, 1:0.4, and 1:0.5. The mixture was then analyzed for several parameters such as heating value, moisture content, ash content, and flashpoint. The results of heating values ranging from 5.966 calories/ gram to 7.210 calories/ gram, the flashpoint was from 38 ⁰C to 76 ⁰C, the water content was from 51.89% to 54.52%, the ash content was from 12.3% to 18.03%. The results showed that utilization of oil sludge could be used as liquid fuel alternative energy. Keywords: oil sludge, energy alternative, liquid fuel
Elektroplating Grafena-Polianilina pada Stainless Steel sebagai Elektroda pada Elektrolisis Air untuk Produksi Hidrogen: Electroplating of Graphene-Polyaniline on Stainless Steel as Electrodes on Water Electrolysis for Hydrogen Production Rahmiani Gani; Syarifah Rabiatul Adawiah; Arfiani Nur
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.15538

Abstract

Hydrogen production by water electrolysis can be optimalized by improve the working electrode. Stainless steel as working electrode was coated with graphene and polyaniline by using cyclic voltammetry method with Ag/AgCl as reference electrode and Pt as counter electrode. Coated electrodes were characterized by SEM-EDS and cyclic voltammetry method. Furthermore, the synthesized electrode was applied for water electrolysis by adding 1- 5 g/L NaHCO3. The characterization data showed that Stainless steel/Graphene-Polyaniline electrode can be synthesized by using cyclic voltammetry. The coating process was conducted at sweeping rate 10 mV/s on voltage -0.2 to 0.8 V for 10 cycles. The voltammograms showed that the highest cathodic peak current of electrolysis obtained at 0.491 mA by addition 2 g NaHCO3 on SS/G-PANi0,5 electrode, and the highest anodic peak current obtained at 0.191 mA by addition 2 g NaHCO3 on SS/G-PANi0,5 electrode. Based on the overpotential data, the smallest average potential difference of H+ adsorption obtained by SS/G-PANi1,0 electrode, and the smallest average potential difference of H+ desorption obtained by SS/G-PANi0,5 electrode. Keywords: Stainless steel, hydrogen production, electroplating, electrocatalyst, electrolysis
Ekstraksi dan Uji Stabilitas Zat Warna Alami dari Biji Buah Pinang (Areca catechu L.) sebagai Bahan Pengganti Pewarna Sintetik pada Produk Minuman: Extraction and Stability Test of Natural Dyes from Areca catechu L. as a Substitute for Synthetic Dyes in Beverage Products St Chadijah; Sari Ningsih; Ummi Zahra; Syarifah Rabiatul Adawiah; Iin Novianty
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.15541

Abstract

Natural dyes are an alternative dye that is not toxic, environmentally, friendly and easily degraded. Therefore, optimizing the use of body coloring sources is carried out. One of the natural dyes released is tannin from betel nuts. Tannins are polar pigments. This study aims to determine the results of natural dyes in betel nuts and find out the durability produced and known organoleptic results. Dyestuff extraction from betel nuts was carried out with 96% ethanol. Testing the color stability of betel nut seedlings was carried out on the effect of pH, temperature and storage time with the method UV-Vis Spectrophotometer. Then the application of betel nut dyes on beverage products was carried out. The results showed that betel fruit produced tannin dyes in brownish red color with an average tannin content of 28.002 mg/L. Dyes stabilized at pH of 6 by heating at 400C and storage for 2 days. The results of organoleptic tests showed that the extract of areca nut powder can be used as a natural dye in beverage products with a level of color, smell and flavor that emits at a concentration of 0.005 g/mL of dyes. Keywords: Extraction, tannin, areca nuts, color stability, organoleptic
Studi dan Aplikasi Elektroda FeTiO3-TiO2/Ti untuk Degradasi Reactive Blue 160 dengan Metode Fotoelektrokatalisis: Study and Application of Photoelectrocatalytic FeTiO3-TiO2/ Ti Electrode to High-Degradation of Reactive Blue 160 Thamrin Azis; Maulidiyah Maulidiyah; Muhammad Nurdin; Muh. Zakir Muzakkar; Ratna; La Ode Abd Kadir; Viesta Valentin Octavian; T Nurwahida; C Bijang; Haris W
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.15561

Abstract

The manufacture of titanium dioxide (TiO2) electrodes is made by anodizing method and coated with ilmenite (FeTiO3) through a dip-coating technique. The ilmenite (FeTiO3) coated TiO2/Ti plate electrode was developed for the degradation of the reactive blue 160 dye under photoelectrocatalytic UV and Visible light irradiation. The performance of FeTiO3-TiO2 / Ti composites degrades reactive blue 160 under UV irradiation and is visible photoelectrocatalytically compared to TiO2. The results of XRD characterization of TiO2 crystals in the form of anatase at 2θ, namely 35.1 ° (110), and the substitution of Fe dopant on TiO2 in the form of anatase and rutile crystals. FTIR data indicated the presence of Fe-O bonds at wave numbers <700 nm. SEM-EDX results showed a thin layer of FeTiO3 was formed, indicating that the dip-coating method was effective in the coating process. The performance of the FeTiO3-TiO2 / Ti electrode has the highest activity against the oxidation process under visible light than the TiO2/Ti electrode. The results of degradation of reactive blue 160 dye with a concentration of 0.5 ppm by photoelectrocatalytic showed that the TiO2 / Ti and FeTiO3-TiO2/Ti electrodes were active in visible irradiation with degradation rate constants of 48% and 69%. Keywords: Electrodes, ilmenite, TiO2 / Ti, degradation, reactive blue 160, photoelectrocatalysis

Page 1 of 1 | Total Record : 8

 1 

Filter by Year

2021 2021


Reset
Filter By Issues
All Issue Vol. 11 No. 2 (2025): December Edition Vol. 11 No. 1 (2025): August Edition Vol. 10 No. 3 (2024): December Edition Vol. 10 No. 2 (2024): August Edition Vol. 10 No. 1 (2024): April Edition Vol. 9 No. 3 (2023): December Edition Vol. 9 No. 2 (2023): August Edition Vol. 9 No. 1 (2023): April Edition Vol. 8 No. 3 (2022): December Edition Vol. 8 No. 2 (2022): August Edition Vol. 8 No. 1 (2022): April Edition Vol. 7 No. 3 (2021): Edisi Desember Vol. 7 No. 2 (2021): Edisi Agustus Vol. 7 No. 1 (2021): Edisi April Vol. 6 No. 3 (2020): Edisi Desember Vol. 6 No. 2 (2020): Edisi Agustus Vol. 6 No. 1 (2020): Edisi April Vol. 5 No. 3 (2019): Edisi Desember Vol. 5 No. 2 (2019): Edisi Agustus Vol. 5 No. 1 (2019): Edisi April Vol. 4 No. 3 (2018): Edisi Desember Vol. 4 No. 2 (2018): Edisi Agustus Vol. 4 No. 1 (2018): Edisi April Vol. 3 No. 3 (2017): Edisi Desember Vol. 3 No. 2 (2017): Edisi Agustus Vol. 3 No. 1 (2017): Edisi April Vol. 2 No. 3 (2016) Vol. 2 No. 2 (2016) Vol. 2 No. 1 (2016) Vol. 1 No. 1 (2015) More Issue