Narsito Narsito
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO BOX BLS 21 Yogyakarta 55281

Published : 43 Documents

Found 23 Documents
Journal : Indonesian Journal of Chemistry

Indonesian Journal of Chemistry Vol 1, No 2 (2001)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6429.473 KB) | DOI: 10.22146/ijc.21952


In the present work, some fundamental aspects of the formation of gaseous lead hydride from aqueous solutions containing divalent lead ions (Pb2+) and its application in the atomic absorption spectrometric analysis lead has been investigated. By utilizing a peristaltic pump, an acidic solution of Pb2+ was first oxidized with ammonium peroxodisulphate, NH4S2O8, and followed by reduction with sodium tetrahydroborate, NaBH4. After a gas-liquid separation, the gaseous lead hydride produced was directly swept into an electrically heated open ended quartz tube, located at the light path of an atomic absorption spectrometer in order to have possibilities for specific atomic absorption spectroscopic measurements. The absorbance signals caused by lead atomic absorption could be used proportionally to estimate the density of atomic lead vapor produced in the thermal decomposition under investigation. Results showed that on-line pre-oxidation of the analyte is very important and crucial step in the gaseous hydride generation of lead, and no lead hydride was produced without the involvement of this step. Moreover, it was observed that the use of low major gas flows cannot be applied in quantitative atomic absorption spectrometric determination of lead by this technique. This condition may result in possible losses of the analyte atomic vapor due to metallic condensation.
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (100.384 KB) | DOI: 10.22146/ijc.21645


The kinetics of photo-reduction of manganese(IV) oxide, MnO2 in aqueous medium, in the presence of humic acid has been investigated, including the possibility for the involvement of such radicals in the reduction. Results showed that in aqueous medium, the efficiency of the photo-reduction of MnO2 producing a soluble ionic Mn(II) was governed strongly by an internal electron transfer within an intermediate of HA-MnO2 anion complex, resulted in the chemical adsorption of humic acid on MnO2 surface. It was observed that under solar radiation and atmosphere containing oxygen, the rate of MnO2 reduction increased considerably, by factors of about 46 and 2 respectively. Moreover, there was evidence that some radicals certainly played a role in the photo-reduction of MnO2, since radical scavenger addition significantly decreased the reduction efficiency of MnO2. In the present of an excess of propanol-2, however, which was expected to remove all OH radicals present, only about 60 % decrease in reduction efficiency were observed, suggesting that radicals other than OH radical are involved in the reduction of MnO2. It was observed further that the presence of iron(III) in MnO2 up to 1 % (w/w) did not alter the reduction efficiency of MnO2.
ADSORPTION OF Mg(II) AND Ca(II) ON DISULFONATO-SILICA HYBRID Azmiyawati, Choiril; Nuryono, Nuryono; Narsito, Narsito
Indonesian Journal of Chemistry Vol 12, No 3 (2012)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (438.099 KB) | DOI: 10.22146/ijc.21334


Adsorption of Mg(II) and Ca(II) on disulfonato-silica hybrid (DSSH) in the aqueous solution has been studied. The hybrid was synthesized by sol-gel process with sodium silicate solution from rice hull ash, chloroprophyltrimethoxysilane (CTS) and 4-amino-5-hydroxy-naphtalene-2,7-disulfonic acid monosodium salt (ANSNa) as silica source, cross linker and active group, respectively. Sodium silicate solution was reacted with CTS and ANSNa that were added dropwise. Adsorption of magnesium and calcium ions on DSSH was carried out in a batch system. Solution pH significantly affected magnesium and calcium adsorption and the optimum condition was obtained at pH = 6. The synthesized DSSH showed a high adsorption capacity of 0.0844 mmol/g and 0.1442 mmol/g for Mg(II) and Ca(II), respectively. The adsorption isotherm obtained with Langmuir isotherm model gives the negative values of ΔG°, i.e. -23.334 kJ/mol and -22.757 kJ/mol for Mg(II) and Ca(II), respectively, indicating the spontaneous process of adsorption. Kinetic studies showed that the adsorption of Mg(II) and Ca(II) ions onto HDSS follows the pseudo-second-order kinetics.
Cadmium Adsorption on Chitosan/Chlorella Biomass Sorbent Prepared by Ionic-Imprinting Technique Shofiyani, Anis; Narsito, Narsito; Santosa, Sri Juari; Noegrohati, Sri; Zahara, Titin Anita; Sayekti, Endah
Indonesian Journal of Chemistry Vol 15, No 2 (2015)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (390.111 KB) | DOI: 10.22146/ijc.21210


Ionic-Imprinted Chitosan/Chlorella biomass sorbent (IICCb) has been synthesized for selective adsorption of Cd(II) adsorption. IICCb was prepared by coating Cd(II)-complexed-chitosan hydrogel on the biomass surface followed by cross-linking procedure. Cd(II)-imprinting ions were then eluted using Na2EDTA solution to provide a specific template for binding sites of Cd(II). Batch adsorption was carried out as function of initial pH, contact time, and initial concentration of the Cd(II) solution. Result showed that the optimum adsorption of Cd(II) was found at pH 4-6. Study of pseudo-second order kinetic showed that the adsorption of Cd(II) on IICCb went faster than that on Ionic-Imprinted Chitosan (IIC) or Non-Imprinted Ionic Chitosan/Chlorella sorbent (NIICCb). The maximum Cd(II) adsorption capacity as obtained from Langmuir adsorption isotherm was found to be 53.76 mg/g on IICCb, that was comparatively higher than that on IIC (44.44 mg/g) or on NIICCb (51.02 mg/g) adsorbent.
Retracted-Enhanced X-Ray Absorption Property of Gold-Doped Single Wall Carbon Nanotube Alimin, Alimin; Narsito, Narsito; Kartini, Indriana; Santosa, Sri Juari
Indonesian Journal of Chemistry Vol 15, No 3 (2015)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (367.573 KB) | DOI: 10.22146/ijc.21187


Enhanced X-ray absorption property of single wall carbon nanotube (SWCNT) through gold (Au) doping (Au@SWCNT) has been studied. Mass attenuation coefficient of SWCNT increased 5.2-fold after Au doping treatment. The use of ethanol in the liquid phase adsorption could produce Au nanoparticles as confirmed by the X-ray Diffraction (XRD) patterns. The possibility of gold nanoparticles encapsulated in the internal tube space of SWCNT was observed by transmission electron microscope technique. A significant decrease of nitrogen uptakes and upshifts of Radial Breathing Mode (RBM) of Au@SWCNT specimen suggest that the nanoparticles might be encapsulated in the internal tube spaces of the nanotube. In addition, a decrease intensity of XRD pattern of Au@SWCNT at around 2θ ≈ 2.6° supports the suggestion that Au nanoparticles are really encapsulated into SWCNT.
Physical Characteristics of Chitosan Based Film Modified With Silica and Polyethylene Glycol Mahatmanti, F. Widhi; Nuryono, Nuryono; Narsito, Narsito
Indonesian Journal of Chemistry Vol 14, No 2 (2014)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (343.738 KB) | DOI: 10.22146/ijc.21249


Recently, development of film materials is focused on finding the films with high chemical and physical stabilities. Organic based material such as chitosan produces films with low physical stability, and hence addition of inorganic materials necessary. In this research, the effect of silica and polyethylene glycol (PEG) addition on the properties of chitosan based films has been investigated. Precursors used to produce films included chitosan with the deacetylation degree of 83% and sodium silicate solution as the silica source. A simple synthesis in a one-pot process was carried out by mixing 1%(w) of chitosan solution in 2%(v/v) acetate acid and sodium silicate solution (27% SiO2) in various composition ratios and casting the solution on a glass dish. The tensile strength and percentage of elongation decrease with increasing the silica content. The tensile strength tends to decline with addition of PEG, but the elongation percentage of the film increases. Hydrophilicity of the film decreases with the addition of silica and increases with the addition of PEG. The addition of silica and PEG does not change significantly the morphology of the film and functional groups indicating the domination of physical interaction among active sites in the film components.
EFFECT OF AGING TIME TOWARD CRYSTALLINITY OF PRODUCTS IN SYNTHESIS OF MESOPOROUS SILICATES MCM-41 Suyanta, Suyanta; Narsito, Narsito; Wahyuni, Endang Tri; Triyono, Triyono; Sutarno, Sutarno
Indonesian Journal of Chemistry Vol 10, No 3 (2010)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (175.14 KB) | DOI: 10.22146/ijc.21435


Researches about the effects of aging time toward crystallinity of products in the synthesis of mesoporous silicates MCM-41 have been done. MCM-41 was synthesized by hydrothermal treatment to the mixture of sodium silicate, sodium hydroxide, cetyltrimetylammoniumbromide (CTMAB) and aquadest in the molar ratio of 8Na2SiO3 : CTMAB : NaOH : 400H2O. Hydrothermal treatment was carried out at 110 °C in a teflon-lined stainless steel autoclave heated in the oven, with variation of aging time, i.e.: 4, 8, 12, 16, 24, 36, 48, and 72 h respectively. The solid phase were filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcinations at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined powders were characterized by using FTIR spectroscopy and X-ray diffraction method. The relative crystallinity of products was evaluated based on the intensity of d100 peaks. The best product was characterized by using N2 physisorption method in order to determine the specific surface area, mean pore diameter, lattice parameter, and pore walls thickness. It was concluded that the relative crystallinity of the products was sensitively influenced by the aging time. The highest relative crystallinity was achieved when used 36 h of aging time in hydrothermal treatment. In this optimum condition the product has 946.607 m2g-1 of specific surface area, 3.357 nm of mean pore diameter, 4.533 nm of lattice parameter, and 1.176 nm of pore walls thickness.
Indonesian Journal of Chemistry Vol 1, No 3 (2001)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (128.043 KB) | DOI: 10.22146/ijc.21940


An adsorbent was prepared by impregnating 2-mercaptobenzo-thiazole onto polystirene treated diatomaceous earth support. This adsorbent was then applied to adsorb mercury(II) in aqueous medium. The mercury(II) adsorption characteristics of the adsorbent was studied by the use of the original diatomaceous earth as reference. Interaction of mercury(II) and both of diatomaceous earth as well as MBT-diatomaceous were performed in a aqueous batch system to include the following parameters: (a) medium acidity and (b) mercury(II) adsorption characteristic on MBT-diatomaceous with and without the present of other metal ions. In the present work quantification of mercury(II) adsorption was done by determining the mercury concentration left in the solution after adsorption. A cold vapour-generation atomic absorption spectroscopy technic was used in this determination.The experiment results show, that the adsorption affinity of MBT-diatomaceous is higher than the original diatomaceous earth. The total adsorption energy of mercury(II) for diatomaceous earth (24.702 kJ/mol) and MBT-diatomaceous (46.942 kJ/mol) suggest that the interaction is chemisorption. The mercury(II) maximum adsorption on diatomaceous earth is obtained at pH 6, while similar adsorption on MBT-diatomaceous practically was not influenced by pH changes. The present of other metals, i.e. Fe(III), Co(II), Ni(II), Cu(II), Cd(II) and Zn(II) in solution does not give any appreciable influence to the adsorption affinity of MBT-diatomaceous to mercury(II); the total sum of the mercury(II) adsorbed is constantly high, almost 100 %. Keyword: Impregnation, MBT-diatomaceous, adsorption, mercury(II)
Indonesian Journal of Chemistry Vol 9, No 1 (2009)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1325.272 KB) | DOI: 10.22146/ijc.21557


The effect of synthesis parameters to the physical properties of pillared saponite and pillared montmorillonite was examined. Mol ratio of Al to clay mass in the range 1.0 - 5.0 and two different calcination methods; conventional calcination and microwave irradiation method are evaluated as controlling factors to evolution of basal spacing d001 , surface acidity, specific surface area, pore distribution and catalytic activity in phenol hydroxylation reaction. XRD, FTIR, and N2-adsorption/desorption analysis were used to characterize the materials. Results showed that pillarization produced higher basal spacing d001 and surface acidity and crystalinity of materials in all Al/clay ratio and in both of the calcination methods. In general, Al to clay mass ratio and calcination method remarkably influence to the basal spacing d001, surface acidity and material crystallinity, but the effect of these factors to catalyst activity in phenol hydroxylation depends on nature of clay. It is concluded that the activity as catalyst is affected by the presence of ionic species and surface acidity in the minerals.     Keywords: Pillared smectite, surface acidity, calcination
IMMOBILIZATION OF PAPAIN ON CHITOSAN Cahyaningrum, Sari Edi; Narsito, Narsito; Santoso, Sri Juari; Agustini, Rudiana
Indonesian Journal of Chemistry Vol 8, No 3 (2008)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1177.439 KB) | DOI: 10.22146/ijc.21609


In this study, papain was immobilized on chitosan with Mg(II) cosslinked agent. Studies on free and immobilized papain systems for determination of optimum pH, optimum temperatur, thermal stability and reusability were carried out. The results showed that free papain had optimum pH 6.5 and optimum temperature 55 °C while the immobile papain hadoptimum pH 8 and optimum temperature 80 °C. The thermal stability of the immobilized papain, relative to that of the free papain, was markedly increased. The immobilized papain can be reused for at least six times.   Keywords: papain, immobilization, chitosan