State 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.
State 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.
Int J Biol Macromol. 2019 Oct 15;139:352-360. doi: 10.1016/j.ijbiomac.2019.07.207. Epub 2019 Jul 31.
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 (R > 0.97), and the adsorption isotherms adapted well with the Freundlich model (R > 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.
新型壳聚糖基吸附剂（CS-DEO-SP）通过使用二环氧辛烷（DEO）和亚精胺（SP）顺序交联和胺化成功制备，用于增强从水溶液中吸附 Cr(VI)。用 1.5mg/L 的 SP 在 50°C 下反应 5h 制备出最优的 CS-DEO-SP 珠。所制备的珠表现出非均相和多孔表面。改性吸附剂的比表面积（79.6%）、孔体积（86.0%）和孔径（31.2%）的增加证明了壳聚糖珠的成功修饰。Cr(VI)离子在制备的 CS-DEO-SP 珠上的吸附动力学很好地符合伪二级模型（R>0.97），吸附等温线很好地符合 Freundlich 模型（R>0.96）。实验数据表明，Cr(VI)离子在 CS-DEO-SP 珠上的吸附极依赖于溶液 pH 值，在酸性条件（pH 2.0）下达到 358.1mg/g 的最大吸附容量。使用 1.0mol/L NaOH 对用过的 CS-DEO-SP 珠进行再生后，在五个连续的吸附循环中，再用吸附剂的吸附容量逐渐下降。总体而言，制备的 CS-DEO-SP 珠在酸性溶液中表现出良好的稳定性和 Cr(V)吸附性能，因此可用作从酸性金属电镀废水中去除 Cr(VI)离子的有效吸附剂。
