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A Facile and Efficient Approach for the Production of Reversible Disulfide Cross-linked Micelles
Published on: December 23, 2016
Preparation of aminated cross-linked chitosan beads for efficient adsorption of hexavalent chromium
Mohammadtaghi Vakili1, Shubo Deng2, Dengchao Liu2
1State Key Joint Laboratory of Environment Simulation and Pollution Control, Beijing Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing 100084, China; Green Intelligence Environmental School, Yangtze Normal University, Chongqing 408100, China.
Abstract:
Novel chitosan-based adsorbent (CS-DEO-SP) was successfully prepared by cross-linking and amination using diepoxyoctane (DEO) and spermine (SP) sequentially for the enhanced adsorption of Cr(VI) from aqueous solutions. The optimal CS-DEO-SP beads were prepared with 1.5 mg/L of SP for 5 h at 50 °C. The prepared beads exhibited heterogeneous and porous surfaces. The increased surface area (79.6%), pore volume (86.0%), and pore size (31.2%) of the modified adsorbent evidenced the successful modification of chitosan beads. The adsorption kinetics of Cr(VI) ions onto the prepared CS-DEO-SP beads was well fitted by the pseudo-second-order model (R2 > 0.97), and the adsorption isotherms adapted well with the Freundlich model (R2 > 0.96). The experimental data revealed that the adsorption of Cr(VI) ions on the CS-DEO-SP beads was extremely dependent on solution pH, and the maximum adsorption capacity of 358.1 mg/g was achieved at acidic condition (pH 2.0). After the regeneration of spent CS-DEO-SP beads using 1.0 mol/L NaOH, the adsorption capacity of reused adsorbent gradually declined within five consecutive adsorption cycles. Overall, the prepared CS-DEO-SP beads showed excellent stability in acidic solution and Cr(V) adsorption performance and thus can be used as an efficient adsorbent for eliminating Cr(VI) ions from acidic metal-plating wastewater.
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