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Sri Juari Santosa

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

Author-ID : 3958144

Chemical Engineering, Chemistry & Bioengineering Chemistry

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SYNTHESIS OF POLYPROPYLCALIX[6]ARENE FROM p-t-BUTYLPHENOL AS ADSORBENT FOR Cr(III) METAL ION Susy Yunita Prabawati; Jumina Jumina; Sri Juari Santosa; Mustofa Mustofa
Indonesian Journal of Chemistry Vol 11, No 1 (2011)
Publisher : Universitas Gadjah Mada

A study has been conducted to synthesize a novel polypropylcalix[6]arene polymer using p-t-butylphenol as a starting material. It was of interest to investigate the capability of the polymer with a tunnel-like structure, as adsorbent to trap the heavy metal cation such as Cr3+. The synthesis was carried out in several steps i.e (1) formation of p-t-butylcalix[6]arene from p-t-butylphenol as a starting material, (2) treatment of p-t-butylcalix[6]arene with 4.95 equivalents of allyl bromide under alkaline conditions to yield p-t-butyl-37,40-diallyloxy-38,39,41,42-tetra-hydroxy-calix[6]arene, and (3) polymerization of p-t-butyl-37,40-diallyloxy-38,39,41,42-tetrahydroxycalix[6]arene by treatment with concentrated sulfuric acid to yield polypropyl-calix[6]arene. The application of polypropylcalix[6]arene for trapping Cr(III) was investigated by stirring the suspension of calixarene under variation of pH, time, and adsorbent mass. IR and 1H NMR spectra, showed that two allyl groups had been incorporated to the lower rim of the p-t-butylcalix[6]arene and the polymer was obtained as brownish green crystals with the melting point of 108-110 °C. The study also showed that the polypropylcalix[6]arene was able to trap Cr(III) cation. The optimum adsorption conditions were achieved at pH 5, contact time 60 min and concentration 12 mg/l for every 0,008 g of polymer.

DETERMINATION OF RATE CONSTANT AND STABILITY OF ADSORPTION IN COMPETITIVE ADSORPTION OF Cr(III) AND Cd(II) ON HUMIC ACID BY USING THE NEW MODEL OF KINETIC FORMULATION Suyanta Suyanta; Sri Sudiono; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 4, No 3 (2004)
Publisher : Universitas Gadjah Mada

Determination of rate and stability constants of adsorption in competitive adsorption of Cr(III) and Cd(II) on humic acid by using the new model of kinetic formulation has been done. The new model based on assumption that those adsorption was first order adsorption rearched equilibrium.Humic acid was isolated from Peat moss of Silaut- West Sumatra by modificated Schnitzer method. Humic acid characterization was conducted by using infrared spectrophotometer with KBR pellet method. The experiment of kinetic adsorption was conducted in batch system reactor using erlenmeyer at 25 ± 0.01 oC of water steam bath and in a series of sampling procedure. Initial concentration of both Cr(III) and Cd(II) was 4x10-4 M. Thirty milligrams of humic acid was added to 200 mL of metal solution, and then stirred continuously. At the fixed periode of time, 10 mL of sample was taken using a syringe, then filterd with 0.45 µm filter paper. Concentration of Cr(III) and Cd(II) in the filtrate was determinated by AAS, while that was adsorbed by humic acid was equal to difference between initial and equilibrium concentration. It was concluded that competitive adsorption of Cr(III) and Cd(II) on humic acid was first order adsorption rearched equilibrium as proposed in this research. Adsorption rate constant of Cr(III) on humic acid at competitive condition was greater than of Cd(II), but on the contrary for stability constant (K). Competition between Cr(III) and Cd(II) to interact with the active side of humic acid was dominated by Cr(III).

REDUCTION AND OXIDATION PROCESSES OF CHROMIUM IN HUMIC ACID SUBFRACTION-SENSITIZED PHOTOCATALYST Uripto Trisno Santoso; Herdiansyah Herdiansyah; Sri Juari Santosa; Dwi Siswanta
Indonesian Journal of Chemistry Vol 4, No 3 (2004)
Publisher : Universitas Gadjah Mada

The process of reduction and oxidation of soluble chromium in humic acid subfraction-sensitized photocatalyst was studied. Humic acid was extracted from peat soil sampled in Gambut District, South Kalimantan. Humic acid (HA) was fractionated to humic acid subfraction (HAS) by centrifugation method. ZnO and TiO2 were applied as the photocatalysts produced by Merck, suspended in solution of 2 g/L. Two germicide UV lamps 30 watt (Philip®) was placed in a box at 20 cm above the samples. The results showed that HA or HAS sensitized the photoreduction of Cr(VI) by photocatalyst. The low molecular weight of HAS is more effective to act as sensitizer than the high molecular weight one. The yield of the photoreduction of Cr(VI) with photocatalysts enhanced both in the presence of Fe(II) ion and HAS. UV irradiation of the MnO4- solutions containing Cr(III) induced the photooxidation of Cr(III) to Cr(VI). The presence of Fe(III) or HAS doesn't inhibit significantly. The inhibition is enhanced by the present of both HAS and Fe(II) or HAS and Fe(III). This inhibition is enhanced more by the presence of ZnO or TiO2 photocalysts.

STUDY ON THE RATE OF REDUCTION OF Cr(VI) TO Cr(III) BY HUMIC ACID USING CONTINUM MULTICOMPONENT MODEL Uripto Trisno Santoso; Herdiansyah Herdiansyah; Wega Trisunaryanti; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 4, No 1 (2004)
Publisher : Universitas Gadjah Mada

The objective of this study is to develop a rate equation for reduction of Cr(VI) by humic acid (HA) using a continuum multicomponent model. HA was extracted from peat soil samples in Gambut Subdistrict, South Kalimantan. Parameters influencing the rate of reduction, i.e., medium acidity ([H+]), as well as initial humic acid concentrations ([HA]o) and initial Cr(VI) concentrations ([Cr(VI)]o) were critically evaluated. Experiments were performed in triplicate tests. Aliquots of stock solution containing 100 mg/L HA were equilibrated for 24 h at pH 1.5, 2.05, 3.2, 5.6, and 6.5 before being spiked with 0.02 mM of Cr(VI). [Cr(VI)] was determined by 1,5-diphenylcarbazide spectrometric method. A similar set of rate experiments was conducted at a fixed pH of 1.5 and an [Cr(VI)]o of 0.02 mM and with [HA]o of 25, 50, 75, 100, 150, 200, and 250 mg/L. A third set of batch experiment was performed at pH 1.5, an [HA]o of 100 mg/L, and [Cr(VI)]o 0.01, 0.02, 0.05, 0.10, and 0.20 mM. The results showed that the rate of reduction cannot be adequately modeled by either a simple first- or second- order rate equation. A continum multicomponent model adequately describes the effect of solution parameters on the rates of Cr(VI) reduction.

Co-Authors Dwi Siswanta Herdiansyah Herdiansyah Herdiansyah Herdiansyah Jumina Jumina Mustofa Mustofa Sri Sudiono Susy Yunita Prabawati Suyanta Suyanta Uripto Trisno Santoso Uripto Trisno Santoso Wega Trisunaryanti

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