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Congo red adsorption from aqueous solutions by using chitosan hydrogel beads impregnated with nonionic or anionic
Sudipta Chatterjee1, Dae S Lee, Min W Lee
1Department of Chemical Engineering, Hanbat National University, Yuseong-gu, Daejeon, Republic of Korea.
Bioresource Technology
|April 11, 2009
Summary
Chitosan (CS) beads modified with Triton X-100 (TX-100) or sodium dodecyl sulfate (SDS) effectively remove Congo red dye. This surfactant modification significantly enhances dye adsorption capacity compared to unmodified CS beads.
Area of Science:
- Environmental Chemistry
- Materials Science
- Surface Chemistry
Background:
- Wastewater treatment requires efficient methods for removing anionic dyes.
- Chitosan (CS) beads are potential adsorbents, but their capacity can be limited.
- Surfactant modification offers a strategy to enhance adsorbent performance.
Purpose of the Study:
- To investigate the effect of nonionic (Triton X-100) and anionic (sodium dodecyl sulfate) surfactants on chitosan bead adsorption capacity for Congo red dye.
- To determine the optimal surfactant concentrations for enhanced dye removal.
- To understand the adsorption mechanism using isotherm modeling.
Main Methods:
- Preparation of chitosan beads impregnated with varying concentrations of Triton X-100 and sodium dodecyl sulfate.
- Batch adsorption experiments using Congo red dye in aqueous solutions.
- Analysis of adsorption data using the Sips isotherm model to determine adsorption capacity and mechanism.
Main Results:
- CS beads impregnated with Triton X-100 showed enhanced adsorption capacity for Congo red at all tested concentrations (0.005-0.1%).
- CS beads with sodium dodecyl sulfate showed increased adsorption capacity at low concentrations (<0.01%), but capacity decreased at higher concentrations.
- The Sips isotherm model accurately described the heterogeneous adsorption process, with maximum adsorption capacities of 378.79 mg/g for CS/TX-100 and 318.47 mg/g for CS/SDS, significantly higher than unmodified CS beads (223.25 mg/g).
Conclusions:
- Impregnating chitosan beads with nonionic surfactants like Triton X-100 is an effective strategy to significantly enhance anionic dye adsorption.
- Anionic surfactants like SDS can enhance adsorption at low concentrations but may inhibit it at higher concentrations.
- Modified chitosan beads offer a promising and efficient solution for the removal of anionic dyes from wastewater.
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