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All Journal Natural Science: Journal of Science and Technology KOVALEN: Jurnal Riset Kimia Indonesian Journal of Chemistry
Erwin Abdul Rahim
Jurusan Kimia FMIPA Universitas Tadulako
Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT

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Journal : KOVALEN: Jurnal Riset Kimia

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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.
PRODUKSI METIL OLEAT MELALUI REAKSI METANOLISIS MINYAK BIJI KELOR (Moringa oleifera Lam) Fatiah Riskah; Ahmad Ridhay; Mappiratu Mappiratu; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 1 (2019): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (656.369 KB) | DOI: 10.22487/kovalen.2019.v5.i1.14561

Abstract

Telah dilakukan penelitian yang bertujuan untuk mendapatkan fraksi massa metil ester asam oleat tertinggi dari rasio minyak biji kelor/metanol (v/v) serta waktu reaksi dalam proses metanolisis minyak biji kelor serta komposisi dari metil ester asam oleat. Penelitian ini dilakukan dengan menggunakan Rancangan Acak Lengkap (RAL) dengan variasi rasio minyak biji kelor/metanol 1:3, 1:4, 1:5, 1:6 dan 1:7 (v/v) serta variasi waktu reaksi 30 menit, 60 menit, 90 menit, 120 menit dan 150 menit. Hasil yang diperoleh menunjukkan bahwa peningkatan rasio minyak biji kelor/metanol  meningkatkan fraksi massa metil ester asam oleat dengan fraksi massa maksimum (72.61%) terdapat pada penggunaan rasio minyak biji kelor/metanol 1:7 (v/v). Demikian pula pada pengaruh waktu reaksi yang menunjukkan bahwa peningkatan waktu reaksi meningkatkan fraksi massa metil ester asam oleat dengan fraksi massa maksimum (78.75%) terdapat pada penggunaan waktu reaksi 150 menit. Berdasarkan hasil analisis GC-MS diperoleh senyawa dominan penyusun metil ester tersebut adalah metil oleat persentase sebesar 48.25%, kemudian metil stearat dengan persentase sebesar 7.67%, selanjutnya metil palmitat dengan persentase sebesar 5.14 dan senyawa yang belum diketahui secara pasti dengan persentase sebesar 38.94%Kata Kunci: Minyak biji kelor, metil oleat,metanolisis
Pembuatan Konsentrat Protein Ampas Tahu Menggunakan Garam Ammonium Sulfat: Manufacturing of Tofu Pulp Protein Concentrate Using Ammonium Sulphate Nurhaeni; Frischa Sari Kencana; Andi Tenri Ajeng; Khairuddin; Prismawiryanti; Syamsuddin; Dwi Juli Puspitasari; Indriani; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 1 (2022): 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.2022.v8.i1.15844

Abstract

Tofu pulp which generally becomes waste can be used as a source of protein concentrate. Protein concentrates from tofu pulp have been obtained at various ratios of tofu pulp: ammonium sulfate and ammonium sulfate salt concentration. The research was conducted to obtain the highest protein yield and content of tofu pulp protein concentrate. This study used a completely randomized design (CRD) with the independent variable being the ratio of tofu pulp filtrate: ammonium sulfate (1:2, 1:3, 1:4, 1:5, 1:6, and 1:7 (v/v)) and concentrations of ammonium sulfate (30, 40, 50, 60, 70, and 80%), while the dependent variables were the yield of protein concentrate and protein content. Production of protein concentrate used the salting-out method with ammonium sulfate salt. The ratio of tofu pulp: ammonium sulfate 70% obtained the best ratio of 1:5 with a yield of 41.6% and protein content of 84.58%. Tofu pulp as industrial waste can be a potential source of protein concentrate because it has a high protein content.
Aktivitas Antibakteri Ekstrak Kulit Batang Tumbuhan Johar (Senna siamea Lam) pada Berbagai Polaritas Pelarut : Antibacterial Activity of Johar (Senna siamea Lam) Stem Bark Extract on Various Solvent Polarities Djumidar; Abd. Rahman Razak; Ahmad Ridhay; Ni Ketut Sumarni; Syamsuddin; Jusman; Nurhaeni; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 2 (2022): 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.2022.v8.i2.15970

Abstract

Johar plant is a type of plant from the Fabaceae family which is widely used in traditional medicine such as malaria, itching and diabetes medicine. This study aims to determine the antibacterial activity of Johar stem bark extract with different levels of solvent polarity on the growth of Staphylococcus aureus and Escherichia coli bacteria and to determine the active compound class by TLC-Bioautography. The extraction of active compounds used a multilevel maceration method starting with n-hexane (non polar), followed by ethyl acetate (semi-polar) and ethanol (polar) solvents. Antibacterial activity testing was carried out by diffusion well method with a concentration variant of 25% and 50%. The results showed that n-hexane, ethyl acetate, and ethanol extract had antibacterial activity against the two test bacteria. Ethyl acetate and ethanol extract from Johar stem bark at a concentration of 50% were classified as very strong antibacterials with inhibition zone diameters against S. aureus, which were 22.02±0.84 mm and 20.16±0.23 mm, respectively. The results of the TLC-Bioautography test showed that the three test extracts had strong antibacterial activity against S. aureus and E. coli. In the n-hexane extract with n-hexane: ethyl acetate (9:1) eluent using Lieberman-Burchard spray reagent, it was suspected that triterpenoid compounds were present. In ethyl acetate extract with n-hexane: ethyl acetate (6:4) eluent and ethanol extract with chloroform: methanol (8:2) eluent using FeCl3 1% spray reagent, it was suspected that the tannin compound was present in both extracts.
Analisis Kadar Kadmium (Cd) dalam Bawang Merah Lokal Palu (Allium cepa L. var. aggregatum) pada Berbagai Lokasi dan Umur Tanam: Analysis of Cadmium (Cd) in Palu Local Shallots (Allium cepa L. var. aggregatum) at Various Locations and Planting Ages Eka Lindawati; Khairuddin Khairuddin; Nurhaeni; Ruslan; Ahmad Ridhay; Husain Sosidi; Erwin Abdul Rahim; Syamsuddin
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.i1.16287

Abstract

The local Palu shallot (Allium cepa L. var. aggregatum) plant is one of the leading products in the Central Sulawesi region. Shallots can experience a decrease in quality if they are contaminated with heavy metals, such as cadmium (Cd) in amounts that exceed the threshold. This study aims to determine the effect of planting age on cadmium levels in local Palu shallots cultivated in Oloboju Village and Solove Village, Biromaru District, Sigi Regency. The research variables used were the planting age which consisted of 4 levels (age 40, 50, 60, and 70 days), and the planting location which consisted of 2 levels (Solove Village and Oloboju Village). Cd levels were analyzed using an Atomic Absorption Spectrophotometer (AAS). Cadmium levels in shallot roots at two planting locations decreased with increasing planting age, from 101.34 - 107.18 mg/kg at 40 days of age to 1.68-3.78 mg/kg at 70 days of age. Shallot bulbs at two locations had lower cadmium levels than roots, namely 0.01-0.04 mg/kg. The results of the study found that planting time had a significant effect on cadmium levels in the roots of shallots, but planting age and planting location had no significant effect on cadmium levels in local Palu shallot bulbs with levels that met the SNI (Indonesian national standard) quality requirements
Pemanfaatan Karbon Aktif Kulit Kacang Tanah untuk Menurunkan Kadar Ion logam Ca2+ dan Mg2+ dalam Air: Utilization Peanut Shell Activated Carbon to Reduce Levels of Ca2+ and Mg2+ in Water Wilda Yanti; Husain Sosidi; Indriani; Prismawiryanti; Dwi Juli Puspitasari; Moh. Mirzan; Erwin Abdul Rahim; Nov Irmawati Inda
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 2 (2023): 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.2023.v9.i2.16397

Abstract

Peanut shell has a high cellulose content as a carbon source which can be used as a basic ingredient for making activated charcoal. Research on peanut shells used as activated charcoal aims to determine the effect of contact time and pH on reducing levels of metal ions Ca2+ and Mg2+ in water. The research was conducted using contact time variables (30, 60, 90, 120, and 150 minutes) and pH (4, 5, 6, 7, and 8). Measurement of adsorbed metal levels was determined by using an Atomic Absorption Spectrophotometer (AAS). The research results obtained showed that variations in contact time could reduce Ca2+ levels by 77.46% -84.89% and Mg2+ by 86.88%-88.91%. Adsorbents with variations in pH can reduce Ca2+ levels by 63.48%-88.74% and Mg2+ by 90.35%-94.49%. The best conditions for the absorption of Ca2+ and Mg2+ ions were a contact time of 60 minutes and pH 4. The adsorbent was applied to reduce Ca2+ and Mg2+ levels in water with different hardness levels. The results of the analysis of water samples from two different locations had Ca2+ levels of 94.180 mg/L and 210.20 mg/L, while Mg2+ levels were 13.536 mg/L and 17.420 mg/L. The percentages of Ca2+ adsorption for the two samples were 96.19% and 77.08%, and the percentages of Mg2+ adsorption for the two samples were 21.16% and 10.63%. Carbon from peanut shells activated with sodium acetate has the potential to be used to reduce hardness in water.
Sintesis dan Karakterisasi Polivinil Alkohol (PVA) Terlapis Polieugenol: Synthesis And Characterization of Polyvinyl Alcohol (PVA) Coated with Polyeugenol Rahim, Erwin Abdul; Ridhay, Ahmad; Sitti Nur Halizah; Indriani; Sosidi, Husain; Khairuddin; Inda, Nov Irmawati; Nurakhirawati; Mirzan, Moh.; Amar, Aini Auliana
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.i1.17088

Abstract

A study has been conducted on materials containing polyvinyl alcohol (PVA) coated with poly eugenol. This research aims to explore the synthesis process and properties of PVA coated with poly eugenol. Characterization of PVA includes tensile strength measurement and surface observation using SEM. Additionally, the antioxidant activity of PVA was also tested using the DPPH method. In this study, PVA films were obtained by dissolving PVA in a water solvent. The characterization results indicate that the tensile strength ranges from 25.56 to 271.10 Mpa, elongation reaches 315.20 to 320%, and the young modulus ranges from 4.05 to 6.27 Mpa. Surface observation with SEM shows a smooth surface without pores. The antioxidant activity test shows IC50 values ranging from 84.11 to 175.37 ppm.
Speciation and Bioavailability of Heavy Metals Pb and Cd in Palu Bay Sediments after the Earthquake and Tsunami Sosidi, Husain; Khairuddin; Ruslan; Abustiana, Rahma Lolita; Ramli, Aksar; Rahim, Erwin Abdul
KOVALEN: Jurnal Riset Kimia Vol. 11 No. 1 (2025): 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.2025.v11.i1.17671

Abstract

Major disturbances to seafloor morphology and input of terrestrial material due to the earthquake- tsunami in Palu City in 2018 have the potential to alter the chemical form (speciation), bioavailability, and flux of lead (Pb) and cadmium (Cd) in Palu Bay sediments. This study was conducted to analyze the speciation of Cd2+ ions and Pb2+ ions and determine the concentration of elusion ions using Diffusive Gradient in Thin Film (DGT). In this study, two methods were carried out, namely the fractionation method and the DGT method. The results showed that the analysis of ion speciation at 3 locations using the fractionation method obtained the highest concentration of Cd2+ ions of 1.4492 mg/L at location 1 and the highest concentration of Pb2+ ions of 0.0200 mg/L at location 3. The results of ion analysis at 3 locations using the DGT method obtained the highest elution yield concentration of Cd2+ ions of 0.0225 mg/L at location 1 and the highest elution yield concentration of Pb2+ ions of 0.0155 mg/L at location 3. This study shows that the presence of heavy metals Pb and Cd in Palu Bay sediments after the earthquake-tsunami is still detected with varying concentrations between locations. The fractionation method is able to describe the distribution of metal speciation in sediments, while the DGT method provides information on labile fractions that are more relevant to bioavailability. The combination of these two methods is important for understanding the potential risk of heavy metals to Palu Bay aquatic ecosystems and can be used as a basis for post-disaster environmental monitoring and management efforts.
Co-Authors A. Risman Abd. Rahman Razak Abustiana, Rahma Lolita achmad rihday Ahmad Kamal Ahmad Ridhay Aini Auliana Amar Andi Nursyafinah Andi Tenri Ajeng Dina Apriana Putri Husni Dini Safitri Djumidar Dwi Juli Puspitasari Dwi Juli Pusptasari Eka Lindawati Fadhillah Fadhillah Fatiah Riskah Fisty Sumangkut Frischa Sari Kencana Gilang Almilda Grace Sita Turumi Hardi Ys Hardi Ys. Heince Andre Pua Husain Sosidi Husain Sosidi Inda, Nov Irmawati Indriani Indriani Indriani Indriani Indriani Indriani Indriani Jaya Hardi Jusman, Jusman Khairuddin Khairuddin Laksono Trisnantoro Mappiratu Mappiratu Megmerio Soro Misba Anggriani Moh. Mirzan Moh. Mirzan Moh. Mirzan Moh. Rifki Saputra Muh. Hajir S. Lasapo Musafira Musafira Musafira Musafira Musafira Musafira Ni Ketut Sumarni Nov Irmawati Inda Nur Istiqomah Nurakhirawati Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Prismawiryanti Prismawiryanti Ramli, Aksar Reflin Yuliana Reski Putriani Demsi Ripdayana Ripdayana Rismawati Sikanna Ruslan Ruslan Ruslan Sitti Ainun Hikmah Sitti Nur Halizah Sulfitri Suardi Sumarni Syaiful Bahri Syaiful Bahri Syamsuddin Syamsuddin WILDA YANTI