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Synthesis of Fulvic Acid-Coated Magnetite (Fe3O4–FA) and Its Application for the Reductive Adsorption of [AuCl4]– Philip Anggo Krisbiantoro; Sri Juari Santosa; Eko Sri Kunarti
Indonesian Journal of Chemistry Vol 17, No 3 (2017)
Publisher : Universitas Gadjah Mada

Fulvic acid-coated magnetite (Fe3O4–FA) has been synthesized through coprecipitation method using NH4OH. Synthesis conducted by cheap and environmentally friendly preparation used iron salts and extracted fulvic acid (FA) from Peat soil of Rawa Pening, Central Java, Indonesia. Characterization using FT–IR indicated that the coating of FA on Fe3O4 occurred through the formation of chemical bond between iron of Fe3O4 and carboxyl group of FA. The XRD measurement indicated that coated Fe3O4 successfully dispersed in smaller size than uncoated Fe3O4, i.e. from 16.67 to 14.84 nm for Fe3O4 and Fe3O4–FA, respectively. Synthesized Fe3O4–FA has pHPZC 6.37 and stable at pH > 3.0. The extracted FA has total acidity 866.61 cmol kg–1, –COOH content 229.77 cmol kg–1 and –OH content 636.84 cmol kg–1. Fe3O4–FA has total acidity 494.86 cmol kg–1, –COOH content 67.80 cmol kg–1 and –OH content 427.06 cmol kg–1. The adsorption rate constant (k) of [AuCl4]– on Fe3O4–A according to the Ho kinetic model was 8006.53 g mol–1 min–1. The adsorption capacity (qmax) according to Langmuir isotherm model was 1.24 × 10–4 mol g–1. The presence of reduction towards the adsorbed [AuCl4]– was shown by the appearance of peaks at 2θ: 37.41; 43.66; 64.25, and 76.67° in the XRD diffractogram.

Synthesis of Gold Nanoparticles Using p-Aminobenzoic Acid and p-Aminosalicylic Acid as Reducing Agent Abdul Aji; Eko Sri Kunarti; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 19, No 1 (2019)
Publisher : Universitas Gadjah Mada

Synthesis of gold nanoparticles (AuNPs) by reduction of HAuCl4 with p-aminobenzoic acid and p-aminosalicylic acid as a reducing agent was investigated. This work was conducted in order to determine the optimum condition of AuNPs synthesis and examine the effect of the hydroxyl group in p-aminosalicylic acid towards the size, shape, and stability of the synthesized gold nanoparticles (AuNPs). The optimum condition of the gold nanoparticles synthesis was determined by UV/Vis spectrophotometer, the shape and size of gold nanoparticles were measured by Transmission Electron Microscope (TEM). The synthesis process was started by reacting HAuCl4 and the reducing agents in an aqueous solution at 86 ºC. The initial gold concentration, reducing agents concentration and pH were varied in order to obtain the optimum condition. In the optimum condition, the results showed that p-aminosalicylic acid containing both hydroxyl and amino groups performed higher reduction ability compared to p-aminobenzoic acid that only containing an amino group. Reducing agents which have a hydroxyl group (p-aminosalicylic acid) could produce AuNPs with a smaller concentration of HAuCl4 than p-aminobenzoic acid. Gold nanoparticles that were synthesized with p-aminosalicylic acid were more stable and had a smaller particle size compared to its counterpart that is synthesized with p-aminobenzoic acid.

The Synthesis and Stability Study of Silver Nanoparticles Prepared by Using p-Aminobenzoic Acid as Reducing and Stabilizing Agent Dian Susanthy; Sri Juari Santosa; Eko Sri Kunarti
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

A study to examine the performance of p-aminobenzoic acid as both reducing agent for silver nitrate to silver nanoparticles (AgNPs) and stabilizing agent for the formed AgNPs has been done. The synthesis of AgNPs was performed by mixing silver nitrate solution as precursor with p-aminobenzoic acid solution and heating it in a boiling water bath. After the solution turned to yellow, the reaction stopped by cooling it in tap water. The formed AgNPs were analyzed by using UV-Vis spectrophotometry to evaluate their SPR absorption in wavelength range of 400–500 nm. The synthesis process was highly depend on the pH, reaction time, and mole ratios of the reactants. The synthesis only occur in pH 11 and at reaction time 30 min, the particle size of the formed AgNPs was 12 ± 7 nm. Longer reaction time increased the reducing performance of p-aminobenzoic acid in AgNPs synthesis but decreased its stabilizing performance. The increase of silver nitrate amount relative to p-aminobenzoic acid in the synthesis increased the reducing and stabilizing performance of p-aminobenzoic acid and the optimum mole ratio between AgNO3 and p-aminobenzoic acid was 5:100 (AgNO3 to p-aminobenzoic acid).

Synthesis of Citrate-Capped Gold Nanoparticles from Reduced [AuCl4]– on Ascorbic Acid-Immobilized Mg/Al Hydrotalcite Agustina Sus Andreani; Suyanta Suyanta; Eko Sri Kunarti; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

Reductive adsorption of [AuCl4]-– by using ascorbic acid immobilized on Mg/Al hydrotalcite (Mg/Al HT) and synthesis of gold nanoparticles (AuNPs) from the reduced gold using sodium citrate have been conducted. Mg/Al HT was synthesized by co-precipitation method at pH 10 with molar ratio of Mg(II) and Al(III) 2:1. Ascorbic acid (AA) was then immobilized on Mg/Al HT to form hybrid of AA and Mg/Al HT (Mg/Al HT-AA). Mg/Al HT-AA was used to reductively adsorb [AuCl4]– and the formed Au(0) was extracted by using sodium citrate to form citrate-capped AuNPs. The formation of AuNPs from 100 mg/L [AuCl4]– solution removed by 60 mg Mg/Al HT-AA was optimum at pH 5.0, by using 70 mM sodium citrate and 2 h sonication time. This optimum condition was successfully applied to synthesize AuNPs from [AuCl4]– as the leaching product of gold from PCB using aquaregia.

Effect of Reaction Time and Stability Properties of Gold Nanoparticles Synthesized by p-Aminobenzoic Acid and p-Aminosalicylic Acid Abdul Aji; Sri Juari Santosa; Eko Sri Kunarti
Indonesian Journal of Chemistry Vol 20, No 2 (2020)
Publisher : Universitas Gadjah Mada

In this work, we determined the influenced of the reaction time at the synthesis of gold nanoparticles (AuNPs) by p-aminosalicylic acid and p-aminobenzoic acid as reducing agent. Besides working as a reducing agent, the p-aminobenzoic acid and p-aminosalicylic acid also simultaneously played a role as a capping agent/stabilizing agent. Gold ion was first mixed with the pH adjusted p-aminobenzoic acid and p-aminosalicylic acid. The mixture then heated in boiling water at 86 °C. The formation of AuNPs was indicated by the appearance of red color and analyzed with UV/Vis spectrophotometry to evaluate their surface plasmon resonance (SPR) absorption in the wavelength range 400–800 nm. The reducing ability of the reducing agents was affected by its structure. Gold nanoparticles that were synthesized with p-aminosalicylic acid were more stable, faster and had a smaller size than its counterpart that is synthesized with p-aminobenzoic acid. The stability test over a periods 5 months showed that AuNPs were relatively stable.

Silver Nanoparticles Capped with p-Hydroxybenzoic Acid as a Colorimetric Sensor for the Determination of Paraquat Gusrizal Gusrizal; Sri Juari Santosa; Eko Sri Kunarti; Bambang Rusdiarso
Indonesian Journal of Chemistry Vol 20, No 3 (2020)
Publisher : Universitas Gadjah Mada

Highly stable silver nanoparticles capped with p-hydroxybenzoic acid were synthesized by reducing silver ion with p-hydroxybenzoic acid and used for the detection of paraquat. The synthesized silver nanoparticles, which are yellow, exhibited an absorption peak at 420 nm when measured with a UV-visible spectrophotometer due to the surface plasmon resonance. In the presence of paraquat, the color of silver nanoparticles changed from yellow to purple accompanied by the appearance of a new peak at 580 nm in addition to the peak at 420 nm. In order to obtain optimum experimental conditions, temperature, and time of reaction were optimized, and the ratio of absorbance obtained at 580 nm and 420 nm (A580/A420) were monitored. The A580/A420 is proportional to the concentration of paraquat. Under the most favorable condition, the calibration curve showed a high level of linearity ranging from 6.0 × 10–4 to 1.0 × 10–3 M, and the detection limit was found to be 8.30 × 10–6 M. Silver nanoparticles capped with p-hydroxybenzoic acid was found to be useful for the colorimetric determination of paraquat in the aqueous medium.

pH Dependence on Colorimetric Detection of Hg2+ by Histidine-Functionalized Gold Nanoparticles Dewi Eviane; Dwi Siswanta; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

In this study, we successfully developed gold nanoparticles capped with histidine (His-AuNPs) for Hg2+ detection using trisodium citrate as the reducing agent. The optimum pH for the detection of Hg2+ by His-AuNPs was 12. The addition of Hg2+ to the His-AuNPs caused the color change from red to black-blue, which is readily detectable by the naked eye. This color change is followed by a decrease in the intensity of the primary Surface Plasmon Resonance (SPR) peak at a wavelength (λ) of 525 nm and an increase in the secondary peak at λ = 650 nm. His-AuNPs effectively detected Hg2+ with limits of detection and quantitation of 1.77 µM and 5.89 µM, respectively. His-AuNPs exhibited good performance for the detection of Hg2+ in waste water collected from a steel industrial facility in Banten Province, with a recovery and a percent relative standard deviation of 115% and 1.02%, respectively.

Assessment of Multi-Nutrients and Heavy Metals in Inorganic Fertilizers Widely Used by Indonesian Farmers Using NAA Sri Murniasih; Sri Juari Santosa; Roto Roto
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.69908

This research aims to determine the concentration of multi-nutrients and heavy metals and investigate the correlation among them in the seven inorganic fertilizers in Indonesia. Sample analysis was carried out using the NAA method. The highest concentrations of macro-nutrients were K (36.54 %) and Cl (18.09%) found in the KCl sample, while Ca (23.01%) was observed in the TSP sample. In the case of micro-nutrients, the highest concentrations of Se (0.36 mg/kg), Ti (597 mg/kg), Br (1.84%), and Ni (2.46 mg/kg) detected in the NPK sample. Meanwhile, the highest concentrations of Co (19.57 mg/kg) and Na (1.40%) were measured in the ZA sample, while Mg, with the highest concentration of 1.78%, was found in the KMgS sample. The micro-nutrients with the highest concentration detected in the TSP sample were Cr (45.96 mg/kg), Zn (342.6 mg/kg), and Mn (1331 mg/kg). Non-essential elements such as U, V, La, Sb, Sm, Th, Hf, Sr, Cs, Tb, Sc, Rb, Ta, and Eu were also detected in the fertilizer samples with the highest concentrations in the TSP sample. Statistical tests of multi-nutrient and heavy metals concentrations indicated that multi-nutrient and heavy metals in fertilizers are complex.

Adsorption of Pb(II) on Calix[4]arene Derivatives: Kinetics and Isotherm Studies Busroni Busroni; Dwi Siswanta; Jumina Jumina; Sri Juari Santosa; Chairil Anwar
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.70665

This study aims to investigate the application of two calix[4]arene derivatives named 5,11,17,23-tetra-(t-butyl)-25,26,27,28-tetrahydroxycalix[4]arene (TBCA) and 5,11,17,23-tetra-(t-butyl)-26,27,28-tribenzoyloxycalix[4]arene (TBMTCA) as adsorbents of Pb(II) from aqueous solution in a batch system. Adsorption was carried out by varying pH solution, exposure time, and concentration. The kinetics was evaluated based on the adsorption in various exposure times using the Lagergren and Ho equations, while the isotherms were analyzed based on the adsorption in various Pb(II) concentrations using the Langmuir and Freundlich equations. Furthermore, the isotherm model showed the Pb(II) adsorption of TBCA and TBMTCA followed Langmuir model with a capacity of 137.29 and 128.46 mg/g, respectively. Based on the adsorption capacity, both adsorbents are the potential for the removal of heavy metal cations from polluted water.

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

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.

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