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All Journal Indonesian Journal of Chemistry
Eko Sri Kunarti
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281, Indonesia
Chemical Engineering, Chemistry & Bioengineering Chemistry

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Controlled Release Fertilizer Encapsulated by Glutaraldehyde-Crosslinked Chitosan Using Freeze-Drying Method Adhitasari Suratman; Dwi Ratih Purwaningsih; Eko Sri Kunarti; Agus Kuncaka
Indonesian Journal of Chemistry Vol 20, No 6 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.55133

Abstract

A new encapsulation of NPK fertilizer hydrogel granules made from glutaraldehyde crosslinked chitosan has been successfully fabricated. This designed fertilizer was aimed to maximize the fertilizing process in the soil, as the environmental pollution affected by the excess release of the nutrients can be prevented. The granule was prepared from biodegradable chitosan crosslinked with glutaraldehyde by applying a method of air and freeze-drying. The release test proved that this designed fertilizer showed a good performance as a Controlled Release Fertilizer (CRF) in which the hydrogel granules could absorb and deposit large amounts of NPK. Later on, they could also release large amounts of NPK as well, unlike several types of CRFs. The release percentage of NPK out of the granules tended to decrease with an increase of pH at a range close to the average pH of the soil, which is neutral to base. Comparing two methods, the freeze-drying technique, which yields a bigger pore size, showed a higher release percentage than air-drying. The release kinetics of the granules followed the Korsmeyer-Peppas model.
Natural Magnetic Particles/Chitosan Impregnated with Silver Nanoparticles for Antibacterial Agents Annisa Afra Martha; Defia Indah Permatasari; Elma Retna Dewi; Nikho Asyoka Wijaya; Eko Sri Kunarti; Bambang Rusdiarso; Nuryono Nuryono
Indonesian Journal of Chemistry Vol 22, No 3 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.68691

Abstract

In this research, silver nanoparticles (AgNP) impregnated on natural magnetic material/chitosan composite (NMP/Chi) have been conducted with different AgNP concentrations (0.5, 1.0, 1.5 mM). Their antibacterial activity was examined against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The AgNP samples were characterized with UV-Vis spectrophotometer and TEM. The NMP/Chi/AgNP samples were identified with FTIR and XRD, while NMP/Chi/AgNP1.0 (with the highest antibacterial activity) were analyzed with TEM and SEM-EDX. The antibacterial test with a well-diffusion method showed that NMP/Chi/AgNP was categorized as a strong antibacterial agent. The composite showing the largest inhibition zone diameters was NMP/Chi/AgNP prepared using 1.0 M AgNO3, namely 14.39 and 16.8 mm against E. coli and S. aureus, respectively. Characterization of AgNP1.0 showed a spherical shape with an average particle diameter of 17.9 nm in suspension and 32.4 nm in NMP/Chi. The presence of 1000 mg/kg NMP/Chi/AgNP1.0 composite in water was able to reduce the growth of E. coli and S. aureus bacteria by 60.4% (from 5.3 to 2.1 CFU/mL) and 71.6% (from 6.34 to 1.86 CFU/mL), respectively, within 5 h. The NMP/Chi/AgNP1.0 showed an effective antibacterial agent against both bacteria (E. coli and S. aureus) and could be applied potentially in aquatic environments.
Enhancing Compressive Strength and Dentin Interaction of Mineral Trioxide Aggregate by Adding SrO and Hydroxyapatite Leny Yuliatun; Eko Sri Kunarti; Widjijono Widjijono; Nuryono Nuryono
Indonesian Journal of Chemistry Vol 22, No 6 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.76231

Abstract

In this research, the effect of strontium oxide (SrO) and hydroxyapatite (HA) on the properties of mineral trioxide aggregate (MTA) have been studied. MTA contained 20% SiO2, 60% CaO, and 2% Al2O3. Bi2O3 and SrO have been added with 18% (w/w) total percentage. MTA was prepared with a sol-gel process using a weak base (NH3) as a catalyst and calcined at 1000 °C for 3 h. The effect of HA was investigated by adding various percentages (3, 6, and 9%) on the MTA modified with 5% SrO. The modified MTA (MTA-SrO-HA) products were hydrated using water with the MTA to water weight ratio of 3:1. The results showed that tricalcium silicate (C3S), dicalcium silicate (C2S), Bi2O3, and strontium silicate peaks were detected in the XRD patterns. An increase in the intensity in the infrared spectra of CaO occurred after hybridization with HA. In addition, bonding of Ca-O-Si appeared at 879 and 995 cm−1, indicating the formation of cement. MTA modified with 5% SrO and 6% HA showed similar compressive strength to the commercial MTA (ProRoot brand). Furthermore, MTA-SrO5/HA6 showed a strong interface interaction with dentin adheres without any gaps, indicating a potential dental material for the future.
Propylamine Silica-Titania Hybrid Material Modified with Ni(II) as the Catalyst for Benzyl Alcohol to Benzaldehyde Conversion Dewi Agustiningsih; Nuryono Nuryono; Sri Juari Santosa; Eko Sri Kunarti
Indonesian Journal of Chemistry Vol 23, No 5 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.84282

Abstract

SiO2-TiO2@propylamine-Ni(II) as the catalyst for the benzyl alcohol oxidation has been synthesized by utilizing rice husk ash as the SiO2 source. This research was started by extracting SiO2 from rice husk ash and continued by synthesizing the SiO2-TiO2 composite using titanium(IV) tetraisopropoxide (TTIP) as TiO2 precursor and PEG-40 as template. The composite functionalization and metal modification were carried out by adding (3-aminopropyl)triethoxysilane (APTES) as the source of propylamine linker and impregnating NiCl2·6H2O as the nickel precursor, respectively. The catalysts were synthesized by varying the ratios between each component within the material. The prepared materials were then characterized using ATR-IR, XRD, XRF, PSA, SAA, AAS, SEM-EDX, HR-TEM, and TGA. The catalyst activity was investigated by applying it to the oxidation reaction of benzyl alcohol to benzaldehyde with H2O2 as the oxidizing agent under sonication system. The obtained products were then analyzed by using GC-MS to quantify the success of the reaction. All characterizations performed in this research generally indicate the success in the synthesis of SiO2-TiO2@propylamine-Ni(II) materials. Under the same condition including at room temperature, 1 h reaction time, and sonication system, the optimal oxidation reaction of benzyl alcohol was reached when SiO2-TiO2@propylamine-Ni(II)5 was used as the catalyst in 98.52% yield.
Fast and Simple Au3+ Colorimetric Detection Using AgNPs and Investigating Its Reaction Mechanism Faathir Al Faath Rachmawati; Bambang Rusdiarso; Eko Sri Kunarti
Indonesian Journal of Chemistry Vol 24, No 1 (2024)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.84446

Abstract

One of the precious metals that has numerous applications is gold. Although it is non-toxic and biocompatible, the oxidized form, Au3+, is toxic and can cause damage to human organs. Detection of Au3+ becomes a necessary and interesting topic to be conducted. Colorimetric analysis using metal nanoparticles such as silver nanoparticles (AgNPs) can analyze metal ions more simply, sensitively, and selectively than traditional methods. In this research, AgNPs were synthesized using polyvinyl alcohol (PVA) and ascorbic acid as stabilizers and reducing agents. The interaction between Au3+ and AgNPs selectively decreased the absorbance intensity of AgNPs and altered the color of colloidal AgNPs from yellow to colorless. These two phenomena indicated a redox reaction between Au3+ and AgNPs, leading to the decomposition of AgNPs. The decomposition of AgNPs (the proposed mechanism) was confirmed by TEM images and UV-vis spectra. The decrease in AgNPs’ absorbance intensity correlated linearly with the increase in added Au3+ concentration. The calibration curve of ∆A versus Au3+ ion concentration yielded LOD and LOQ of 0.404 and 1.347 μg/mL, respectively.
Preparation and Characterization of Magnetic Material/Chitosan Composite Modified with Glycidyl-Trimethylammonium Chloride Feri Mukhayani; Eko Sri Kunarti; Yuichi Kamiya; Nuryono Nuryono
Indonesian Journal of Chemistry Vol 24, No 2 (2024)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.88758

Abstract

Glycidyl-trimethylammonium chloride (GTMAC) containing quaternary ammonium (QA) groups is commonly used as a base catalyst for any organic reaction. This research prepared a novel composite of GTMAC attached to chitosan-coated magnetic material (MM/Chi/GTMAC) using a precipitation method. The effect of chitosan and GTMAC contents on MM/chi/GTMAC properties was studied, where the chitosan content varied from 0, 0.3, 0.5, 1.0, and 3.0 mol, and GTMAC varied from 0, 0.3, 0.8, 1.0, 1.5, and 3 mL with the constant mass of MM (0.4640 g). The physicochemical and morphological properties were characterized with FTIR, SEM-EDX, XRD, TGA, UV-vis, AAS, and zeta-sizer, and the magnetic strength was simply tested with an external magnet. The result showed that a mixture containing chitosan and GTMAC of 0.358 g and 1.5 mL was an optimum composition, in which MM/chi(0.5)/GTMAC(1.5) has high thermal stability, low chitosan and Fe solubility, and optimum content of QA (0.284 mol/g) without loss of magnetic strength. The higher the amount of chitosan, the lower the magnetic properties, and the higher the GTMAC did not increase the QA content. Therefore, the composite produced has the potential to be a novel heterogeneous base catalyst that is quickly recovered from any organic reaction media.
Co-Authors Adhitasari Suratman Agus Kuncaka Agustina Sus Andreani Aji, Abdul Akhmad Syoufian Alfa Akustia Widati Annisa Afra Martha Bambang Rusdiarso Defia Indah Permatasari Dessy Puspa Aryanti Dewi Agustiningsih Dian Susanthy Dwi Ratih Purwaningsih Elma Retna Dewi Faathir Al Faath Rachmawati Feri Mukhayani Fitri Rizki Amalia Gusrizal Gusrizal Hesti Kusumastuti Indriana Kartini Ira Nur Arba’atul Jannah Karolina Martha Widyandari Leny Yuliatun Lia Kurnia Madjid Arie Wibowo Nikho Asyoka Wijaya Nuryono Nuryono Philip Anggo Krisbiantoro Respati Tri Swasono Salim Mustofa Sri Juari Santosa Sutarno Sutarno Suyanta Suyanta W. Widjijono Yuichi Kamiya