Nuryono Nuryono
Chemistry Department, Faculty of Mathematics and Natural Sciences Gadjah Mada University, Yogyakarta

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EFFECT OF ACID CONCENTRATION ON CHARACTERS OF SILICA GEL SYNTHESIZED FROM SODIUM SILICATE Nuryono Nuryono; Narsito Narsito
Indonesian Journal of Chemistry Vol 5, No 1 (2005)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (217.159 KB) | DOI: 10.22146/ijc.21834

Abstract

In this research, synthesis and characterization of silica gel from sodium silicate through sol-gel process using H2SO4, HCl, and citric acid have been investigated. Synthesis was carried out by mixing and stirring  20 mL of H2SO4, HCl or citric acid  at certain concentration with 50 mL of sodium silicate solution (Na2O 0.17 M and SiO2 0.61 M) for one hour and let to form gel.  The gel was washed with distillated water, and dried in an oven at 100 oC. Characterization of silica gel was carried out by determination of acidity, water adsorption capacity, and water content. Identification of functional group and structure were identified using x-ray diffractometer (XRD) and infrared (IR) spectrophotometer, respectively.  Results showed that at a range of investigated concentration (0.6 - 3.0 M) the increase of concentration, formation of gel with H2SO4 tended to be faster, but with HCl and citric acid to be slower. The increase of acid concentration caused water content, water adsorption capacity, and acidity of the silica gel resulted with HCl and citric acid tended to be increased, increased, and increased, but with H2SO4 to be decreased, increased, and decreased, respectively. Based on the IR spectra and XRD data, it could concluded that the synthetic silica gels contained silanol (Si-OH) and siloxane (Si-O-Si) and were amorphous, showing similar pattern to kieselgel G 60 produced by Merck.
THERMODYNAMIC OF Mg(II), Cd(II), AND Ni(II) ADSORPTION ON SULFONIC MODIFIED SILICA GEL Choiril Azmiyawati; Nuryono Nuryono; Narsito Narsito
Indonesian Journal of Chemistry Vol 5, No 1 (2005)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (208.036 KB) | DOI: 10.22146/ijc.21835

Abstract

Silica gel modified with 4-amino-5-hydroxy-2,7-naphtalenedisulphonate (SG-SO3-) has been applied for adsorption of Mg(II), Cd(II), and Ni(II) in aqueous medium. In addition, three thermodynamic parameters i.e. capacity, adsorption constant and energy of adsorption were calculated. Adsorption was conducted in a batch system and metal ion remaining in the solution was determined by atomic adsorption spectrophotometry (AAS). The amount of adsorbed metal ions was calculated from the difference of metal ion concentration before and after interaction. Adsorption parameters i.e. capacity (ns2), constant (b), and energy (E) of adsorption were calculated using the equation of Langmuir isotherm. Results showed that ns2 for Mg(II), Cd(II), and Ni(II) on the adsorbent were 4.67 x 10-4, 1.19 x 10-4, and 0.13 x 10-4mol g-1, respectively. The values of b for Mg(II), Cd(II), and Ni(II) were 49.35 x 105, 173.46 x 105, and 181.12 x 105 g-1, respectively. Furthermore, it was found that E for all metal ion investigated was in the range of 26-30 kJ/mol, indicating the involvement of chemical adsorption.  
EFFECT OF DIATOMEAOUS EARTH TREATMENT USING HYDROGEN CHLORIDE AND SULFURIC ACID ON KINETICS OF CADMIUM(II) ADSORPTION Nuryono Nuryono; Narsito Narsito
Indonesian Journal of Chemistry Vol 2, No 2 (2002)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (66.597 KB) | DOI: 10.22146/ijc.21922

Abstract

In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl) and sulfuric acid (H2SO4) on kinetics of Cd(II) adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size) with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II) in aqueous solution with various concentrations. The Cd(II) adsorbed was determined by analyzing the rest of Cd(II) in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed  that before equilibrium condition reached, adsorpstion of Cd(II) occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order  (step I) followed by reaction of reversible first order (step II). Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min.  However, increasing concentration of acid (in a range of concentration investigated) did not give significant and constant change of adsorption rate constant. For step II process,  adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol).