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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 320 Documents
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Sintesis dan Karakterisasi Katalis Bentonit Termodifikasi TiO2 dan Terinpregnasi Logam Ni : Synthesis and Characterization of TiO2 Modified Bentonite Catalyst and Ni Metal Impregnated Mirzan, Mohamad; Duda, Nining Austi; Khairuddin; Nurakhirawati; Ruslan
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 3 (2024): 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.2024.v10.i3.17411

Abstract

TiO2-modified and Ni-impregnated bentonite catalysts have been synthesized and characterized to determine their physicochemical properties. Ni(NO3)2.6H2O was used as a precursor for impregnation. The physicochemical properties determined include surface acidity by acid-base titration method, FTIR spectrum, and XRF and XRD data. The highest surface acidity value was obtained from the Ni-TiO2/bentonite catalyst sample of 1.57 mmol/g. The results of FTIR analysis showed that the peak at wave number 3441 cm-1 in TiO2/bentonite shifted to 3458 cm-1 in Ni-TiO2/bentonite. The distribution of bentonite content after being pillared with TiO2 = 8.68% and impregnated with NiO = 0.58%. The success of nickel metal impregnation into the TiO2/bentonite support was obtained from XRD data, which was marked by the appearance of a typical Ni peak at 2θ = 37.70° d = 2.38 Å, 2θ = 39.39° d = 2.28 Å, 2θ = 43.02° d = 2.10 Å, 2θ = 51.38°d = 1.77 Å.
Sintesis dan Karakterisasi Komposit Mn-N-TiO2/Bentonit untuk Degradasi Polutan Organik: Synthesis and Characterization of Mn-N-TiO2/Bentonite Composite for Organic Pollutants Degradation Ruslan; Prismawiryanti; Sumarni, Ni Ketut; Ridhay, Ahmad; Riski, Mutiara Zalfa; Nurhalisa, Sitti; Marsela, Anggi
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 3 (2024): 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.2024.v10.i3.17502

Abstract

Research has been conducted on the synthesis and characterization of Mn-N-TiO2/Bentonite composites for the degradation of organic pollutants. This study aims to synthesize the Mn-N-TiO2/Bentonite composite as a catalyst in degrading congo red in visible light and to determine the effect of irradiation time on the effectiveness of photodegradation of congo red catalyzed Mn-N-TiO2/Bentonite. The synthesis of the Mn-N-TiO2/Bentonite composite was carried out using the sol-gel method. Characterization was carried out with UV-Vis DRS, XRD, FTIR, and SEM-EDX. A photocatalytic activity test on Congo red degradation was carried out using ultraviolet and visible lamps. The results of the characterization of the Mn-N-TiO2/Bentonite configuration show that the band gap energy of Mn-N- TiO2/Bentonite with a variation of 5 g has a band gap energy of 2.14 eV with anatase crystal form. In the IR spectrum, there is a shift in wave number from 1634.49 to 1433.11cm-1, there is the vibration of the NO bond, absorption below 1000 cm-1 indicates the presence of Mn-O bonds, and absorption at wave number 1049.28 cm-1 indicates the presence of ions. manganese metal trapped in the TiO2 matrix. This spectrum indicated the presence of manganese and nitrogen. These results were confirmed by the EDX instrument, which showed the presence of 0.60% Mn and 0.04% N. SEM results show that particles that are still agglomerated and have a large size, which is influenced by water vapor in the TiO2 crystal structure. The results showed that the photodegradation activity increased significantly up to 40.9075% at 30 minutes of irradiation for the Mn-N- TiO2/Bentonite composite and 20.0225% under exposure to ultraviolet light.
Profil Morfologi dan Difraksi Arang Hasil Pirolisis Beberapa Jenis Kayu Lokal Provinsi Bengkulu, Indonesia: Morphology and Diffraction Study of Charcoal By-Products from the Pyrolysis of Several Local Woods from Bengkulu Province, Indonesia Nurwidiyani, Ria; Triawan, Deni Agus; Rahman, Arief Aulia; Yudha, Sal Prima
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 3 (2024): 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.2024.v10.i3.17289

Abstract

Wood, as a basic material for the furniture industry, creates waste problems in the form of wood sawdust. Wood sawdust is a material that can be utilized by processing it through a pyrolysis process to produce liquid smoke and charcoal. Charcoal resulting from sawdust pyrolysis of Azadirachta excelsa, Durio zibhetinus, Swietenia mahagoni, and Coffea sp. wood has different characteristics. Pyrolysis was carried out at 300–350 °C for 6 hours. Characterization was carried out using SEM-EDS and XRD. Based on the research, it is known that the character of the charcoal resulting from pyrolysis using XRD shows that the charcoal composition of each wood has similar characteristics, as indicated by the presence of a broad peak at 2 theta 25° indicating that the charcoal formed has an amorphous structure. In comparison, the 2 theta peaks of 17° and 29° respectively, indicate the presence of lignin and CaCO₃ in charcoal. The morphological structure of the charcoal surface based on the results of SEM analysis shows a similarity in morphology between Swietenia mahagoni and Coffea sp. Wood charcoal with small pore diameters and distances apart, as well as between Durio zibhetinus and Azadirachta excelsa wood charcoal, which resembles a honeycomb structure. The composition of charcoal resulting from pyrolysis shows that the largest component of charcoal is carbon with a percentage of 45.4-56%, calcium with a percentage of 10-15.2%, and oxygen with a percentage of 22.5-38.4%, with minor components in the form of aluminum, boron, silicon, and potassium.
Efektivitas Limbah Puntung Rokok sebagai Inhibitor Korosi dalam Medium Asam Klorida pada Baja A36 dengan Metode Microwave Assisted Extraction: Effectiveness of Cigarette Butts Waste as Corrosion Inhibitor in Hydrochloric Acid Medium on A36 Steel by Microwave Assisted Extraction Method Alatif, Ikhsan Akmal; Permatasari, Rahma Puspa; -, Maya Futri Nur Rachmat; Wulandari, Dwi Arsya; Sonia, Gina; Aura, Azma Addina; Trirahayu, Dhyna Analyes; Hadiningrum, Kunlestiowati
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 3 (2024): 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.2024.v10.i3.17395

Abstract

Cigarette butts are one of the wastes found in many places, and their presence can damage the environment. One way to reduce the amount of cigarette butts waste is to process them into corrosion inhibitors. This study aims to extract tobacco from cigarette butts using 96% ethanol solvent by varying the extraction time for 5, 10, 15, and 20 minutes, and microwave power of 150 watts and 300 watts, and calculating the efficiency of corrosion inhibitors in acidic environments. The extraction method used was Microwave Assisted Extraction (MAE). From the extraction process, it is known that the optimum extraction power of 150 watts in 15 minutes produces the highest yield of 64.52%. Based on phytochemical and GC-MS tests, it is known that cigarette butt extract contains antioxidant compounds in the form of alkaloids, pyranones, and terpenoids as corrosion inhibitor compounds. Based on corrosion testing, it is proven that the addition of cigarette butt waste extract corrosion inhibitors can suppress or reduce the corrosion rate that occurs on metals with the most excellent efficiency of 82.26% with an extract concentration of 2000 ppm. And the SEM-EDX test results concluded that the corrosion inhibitor from cigarette butts waste extract can withstand the formation of rust on the metal.
Klasifikasi dan Autentifikasi Tanaman Seurapoh (Chromolaena odorata Linn) Menggunakan Metode Kombinasi Spektroskopi Inframerah dan Kemometrik: Classification and Authentication of Seurapoh Plant (Chromolaena odorata Linn) Using a Combination of Infrared Spectroscopy and Chemometric Methods Karma, Taufiq Karma; Kala, Pasyamei Rembune; Shofi, Shofi; Zafirah, Zafirah
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 3 (2024): 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.2024.v10.i3.17460

Abstract

This study classifies the Seurapoh plant (Chromolaena odorata Linn) collected from various locations across Aceh Province. The analysis aims to determine the influence of geographic differences on the origin of Seurapoh plants by performing classification and authentication. Seurapoh leaf samples in this study were obtained from several locations, including Aceh Besar, Sabang, Southwest Aceh, South Aceh, Aceh Jaya, Bireun, Bener Meriah, and Central Aceh. Classification of Seurapoh leaf extracts was carried out using Principal Component Analysis (PCA), while authentication was conducted using Linear Discriminant Analysis (LDA). The PCA score plot analysis results indicate that it can explain a total data variance of 62%. Based on the PCA score plot, samples generally form three distinct groups: Group 1 consists of samples from the highland region of Gayo, specifically Central Aceh (TA) and Bener Meriah (BM); Group 2 consists of samples from the coastal areas of Aceh, namely Southwest Aceh (ABD), South Aceh (AS), Aceh Jaya (AJ), and Bireun (Br); and Group 3 comprises samples from geothermal manifestation areas of Seulawah Agam and Jaboi. The classifications derived from PCA analysis were subsequently authenticated using LDA. The LDA analysis results indicate that the LDA model, based on cross-validation, accurately predicts the origin locations of Seurapoh leaf samples with a 100% accuracy rate.
Engineering and Application of Fe-TiO2/MOR Zeolite Photocatalysts for the Photodegradation of Methylene Blue Dye Waste Sholikah, Liqanatul Putri; Sumari, Sumari; Permatasari, Suryani Indah
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.i1.17427

Abstract

The use of dyes such as methylene blue is widespread. However, if methylene blue is discharged without prior treatment, it can lead to pollution problems. In this study, the engineering of zeolites and the degradation mechanism of methylene blue using Fe-TiO2/MOR zeolite as a photocatalyst were investigated. XRD characterization results revealed that Fe-TiO2/MOR zeolite has a crystalline phase. Based on XRF characterization, the percentage of Fe and Ti significantly increased, indicating the successful immobilization of TiO2 and doping of Fe3+ into the zeolite structure to form a composite. The morphological analysis of the Fe-TiO2/MOR zeolite composite showed a rough surface, which could affect its surface area. The Fe-TiO2/MOR zeolite photocatalyst has a band gap of 3.08 eV, allowing it to absorb visible light more efficiently. The study on the application of methylene blue photodegradation using Fe-TiO2/MOR zeolite as a photocatalyst demonstrated higher degradation efficiency compared to using inactivated, non-immobilized, and undoped mordenite zeolite. With an optimal mass of 0.03 grams, a contact time of 90 minutes, and a pH of 10, the percentage of degraded methylene blue reached 98.91%. The Fe-TiO2/MOR zeolite composite has the potential to be used as a photocatalyst in methylene blue photodegradation reactions.
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.
Purification of Crude Glycerol Using Regenerated Spent Bleaching Earth as Palm Oil Refinery Process Wahyuni, Sry; Rizka Fadhillah, Dinda
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.i1.17785

Abstract

Spent Bleaching Earth (SBE) is a type of solid waste generated during the palm oil refining process. Several studies have investigated the potential reuse of SBE as a valuable material, particularly as an adsorbent in glycerol purification. Crude glycerol, a by-product of biodiesel and oleochemical production from palm oil, is typically of low quality and contains numerous impurities, including free fatty acids (FFA) and pigmented compounds such as beta carotene and chlorophyll. In this study, SBE was regenerated using various solvents and subsequently calcined at 500 oC for 2 hours. Its surface was further modified with cetyltrimethylammonium bromide (CTAB) to enhance its adsorption capacity. The results showed that SBE regenerated with n-hexane and subjected to calcination exhibited the highest removal efficiency for beta carotene and chlorophyll. Further analysis of the physical and chemical properties of crude glycerol purified using uncalcined, calcined, and CTAB-modified SBE demonstrated that the modified SBE delivered the best adsorbent performance. The purified glycerol using modified SBE had the following characteristics: Moisture content (10.3%), Density (1.25 g/cm3), Free fatty acid (FFA) content (1.2%), Salt content (4.6%), beta-carotene content (0.843 ppm), Chlorophyll content (0.11 ppm) and pH approximately 6.
Comparative Estimation of Some Contaminates in Products of Drinking Water Companies and Government Stations in the City of Mosul Maseer Nejres, Aws
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.i1.17787

Abstract

Recently, the concentrations of heavy metals have increased in water sources, soil and air, and their symptoms have clearly appeared on living organisms and the serious effects they leave on humans, animals and even plants. has become necessary to periodically monitor these metals, including nickel (Ni), cadmium (Cd), lead (Pb)and cobalt (Co). However, the problem does not stop with heavy metals, as there are other parameters that are closely related in one way or another, such as hardness, pH, Total dissolved solids (TDS) and even conductivity (EC), All of these are present in the water under study, in addition to the Microbiological Assessment test to search for pathogens. The environment of Mosul city was chosen as a source for collecting samples from three categories: local water projects, reverse osmosis water sales systems, in addition to companies accredited for sterilizing, bottling and marketing water. These Metals and parameters were studied using an atomic absorption device, and the results were within the limits established in the regulations of international organizations and bodies.
Evaluation of Antioxidant Activity of Branch Extract from Pouteria campechiana (Sawo Walanda) Batari, Nirmala Puteri; Setyo Purnomo, Adi; Seviani, Winda
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.i1.17792

Abstract

The objective of this research was to assess the antioxidant activity of branch extract (Pouteria campechiana) through analysis of bioactive compound content and antioxidant activity. The sample was extracted through maceration, utilizing methanol as the solvent which produced a yield of 6.03 %. The quantity of phenolic constituents in the extract was determined using the Folin-Ciocalteu method, with gallic acid as the standard, yielding a result of 195.22 mg GAE/g extract. The quantity of flavonoid constituents was determined using gallic acid as a standard resulting in a value of 830.5 mg QE/g extract. Antioxidant activity was tested using two methods, namely DPPH and ABTS. The results of the DPPH test showed an inhibition percentage of 91% with an IC50 value of 3,322 ppm, while the ABTS test showed an inhibition of 99% with an IC50 of 2,206 ppm at a concentration of 10,000 ppm. Based on these results, the Pouteria campechiana branch extract has very weak antioxidant activity, suggests a limited potential as natural bioactive compound source.

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