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Journal : Indonesian Journal of Chemistry

IMMOBILIZATION OF HUMIC ACID ONTO CHITOSAN USING TOSYLATION METHOD WITH 1,4-BUTANEDIOL AS A SPACER ARM Uripto Trisno Santoso; Radna Nurmasari; Dewi Umaningrum; Sri Juari Santosa; Bambang Rusdiarso; Dwi Siswanta
Indonesian Journal of Chemistry Vol 12, No 1 (2012)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (420.224 KB) | DOI: 10.22146/ijc.21369

Abstract

Immobilization of humic acid (HA) onto chitosan using tosylation method with 1,4-butanediol as a spacer arm has been evaluated. Chitosan was phthaloylated selectively using phthalic anhydride in dimethylformamide as solvent with addition of 5% water (v/v) as cosolvent prior to be tosylated. N-phthaloyl-chitosan and HA were tosylated using tosyl chloride in excess and triethylamine as catalyst at temperature < 10 °C for 12 h. The 6-O-tosyl-N-phthaloyl-chitosan was reacted with 1,4-butanediol in order to obtain a spacer arm attached chitosan. The 6-O-butanol-N-phthaloyl-chitosan was activated by reacting with tosyl chloride. For evaluation on immobilization of HA on chitosan with and without spacer arm, 6-O-tosylbutane-N-phthaloyl-chitosan was reacted with HA and the 6-O-tosyl-N-phthaloyl-chitosan was reacted with HA. The HA immobilized onto chitosan was characterized by XRD and FTIR spectrophotometric method. The result showed that HA can be immobilized covalently onto chitosan after attaching 1,4-butanediol as spacer arm onto 6-O-tosyl-N-phthaloyl-chitosan and activating the product with tosyl chloride, but HA cannot be reacted directly onto 6-O-tosyl-N-phthaloyl-chitosan.
CHARACTERIZATION OF SORBENT PRODUCED THROUGH IMMOBILIZATION OF HUMIC ACID ON CHITOSAN USING GLUTARALDEHYDE AS CROSS-LINKING AGENT AND Pb(II) ION AS ACTIVE SITE PROTECTOR Uripto Trisno Santoso; Sri Juari Santosa; Dwi Siswanta; Bambang Rusdiarso; Shogo Shimazu
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 (181.878 KB) | DOI: 10.22146/ijc.21434

Abstract

Sorbent produced through immobilization of humic acid (HA) on chitosan using glutaraldehyde as cross-linking agent and Pb(II) ions as active site protector has been characterized. Active sorption site of HA was protected by reacting HA with Pb(II) ion, and the protected-HA was then activated by glutaraldehyde, crosslinked onto chitosan, and deprotected by 0.1 M disodium ethylenediamine tetra-acetic acid (Na2EDTA). The protected-crosslinking method enhanced the content of immobilized-HA and its chemical stability. Based on the FTIR spectra, crosslinking of HA on chitosan probably occurred through a chemical reaction. The sorption capacity of sorbent still remains unchanged after the second regeneration, but some of HA start to be soluble. The latter shows that cross-linking reaction between HA and chitosan is through formation an unstable product. The effectiveness of sorbent regeneration can also be identified by the XRD pattern.
ADSORPTION KINETICS OF Pb(II), Cd(II) AND Cr(III) ON ADSORBENT PRODUCED BY PROTECTED-CROSSLINKING OF HUMIC ACID-CHITOSAN Dewi Umaningrum; Uripto Trisno Santoso; Radna Nurmasari; Rahmat Yunus
Indonesian Journal of Chemistry Vol 10, No 1 (2010)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (295.532 KB) | DOI: 10.22146/ijc.21484

Abstract

Study on adsorption kinetics of of Pb(II), Cd(II) and Cr(III) on adsorbent which was produced by protected-crosslinking of humic acid-chitosan has been done. The Langmuir-Hinshelwood, pseudo first- and second-order kinetics models were used to describe the kinetic data, and the rate constants of adsorption were also evaluated. The experimental data fitted well the second-order kinetics model, indicating that the chemical sorption is the rate-limiting step, instead of mass transfer. The initial metal ion concentration significantly affects the adsorption rate. An increase in initial metal ion concentration results in the decrease in adsorption rate of the metals.
IMMOBILIZATION OF HUMIC ACID ON CHITOSAN BEADS BY PROTECTED CROSS-LINKING METHOD AND ITS APPLICATION AS SORBENT FOR Pb(II) Radna Nurmasari; Uripto Trisno Santoso; Dewi Umaningrum; Taufiqur Rohman
Indonesian Journal of Chemistry Vol 10, No 1 (2010)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (337.212 KB) | DOI: 10.22146/ijc.21485

Abstract

Immobilization of humic acid (HA) on chitosan beads has been done using a protected cross-linking reaction method and the product was then utilized as sorbent for Pb(II). Protection of the active sites of HA was carried out by interacting HA with Pb(II) before performing the cross-linking reaction in order to maintain its adsorption capacity. Protected-HA was cross-linked with chitosan beads using glutaraldehyde in order to obtain sorbent insoluble both in aqueous acidic and basic solution. The result showed that the amount of immobilized HA on beads chitosan was 88.60% by weight. The adsorption capacity of the protected-sorbent beads for Pb(II) was 784 mg/g. As a comparison, the adsorption capacity of the non-protected sorbent beads for Pb(II) was only 142 mg/g.
IMMOBILIZATION OF HUMIC ACID ON CHITOSAN USING PROTECTED CROSS-LINKING REACTION METHOD AND ITS APPLICATION AS SORBENT FOR Pb(II), Cd(II), AND Cr(III) Uripto Trisno Santoso; Dewi Umaningrum; Utami Irawati; Radna Nurmasari
Indonesian Journal of Chemistry Vol 8, No 2 (2008)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (253.04 KB) | DOI: 10.22146/ijc.21620

Abstract

Immobilization of humic acid (HA) on chitosan has been done by using a protected cross-linking reaction method and the product was then utilized as sorbent for Pb(II), Cd(II), and Cr(III). HA was cross-linked with chitosan by using glutaraldehyde in order to obtain sorbent insoluble in aqueous acidic and basic solution. Protection of the active sites of HA was carried out by interacting HA with Pb(II) before performing the cross-lingking reaction in order to maintain its adsorption capacity The result showed that the amount of immobilized HA on chitosan was 99.7% by weight. The solubility of the immobilized HA were < 0.5% at pH 6 and < 1.0% at pH 12. The amount of immobilized HA and its solubility indicated that the protection pretreatment did not interfere the cross-linking reaction between HA and chitosan. The adsorption capacity of the sorbent for Pb(II), Cd(II), and Cr(III) were 416.7 mg/g, 332.3 mg/g, dan 714.3 mg/g, respectively.
STUDY ON SENSITIZATION OF FULVIC ACID ON PHOTOREDUCTION OF Cr(VI) TO Cr(III) BY TiO2 PHOTOCATALYST Uripto Trisno Santoso; Kamilia Mustikasaria; Sri Juari Santosa; Dwi Siswanta
Indonesian Journal of Chemistry Vol 7, No 1 (2007)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (147.265 KB) | DOI: 10.22146/ijc.21708

Abstract

Sensitization of fulvic acid (FA) on photoreduction of Cr(VI) to Cr(III) by TiO2 photocatalyst has been studied. Parameters influencing the sensitization, i.e., pH of medium, as well as FA concentrations, TiO2 concentrations and initial Cr(VI) concentrations were critically evaluated. Extraction of FA from peat soil sampled in Gambut, South Kalimantan, Indonesia, was performed using Amberlite XAD-7 resin. The FA extract then was purified by cation exchange method using Amberlite IRA-120 resin. The TiO2 produced by Merck was used as semiconducting photocatalyst and two 30-W UV lamps (Philips® model TUV) were used as photon source. The results showed that presence of FA on TiO2 suspensions could sensitize the photoreduction of Cr(VI), enhancing of the amount of reduced Cr(VI) more significantly than the sensitization by humic acid. The effectiveness of this sensitization increased with increasing initial concentrations of FA, TiO2, or Cr(VI) until certain concentration, but no further improvement can be observed in excess FA, TiO2, or Cr(VI) concentrations. On the contrary, the effectiveness of this sensitization decreased with increasing of the medium pH.