School of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
J Environ Sci (China). 2014 Dec 1;26(12):2379-86. doi: 10.1016/j.jes.2014.03.005. Epub 2014 Oct 30.
Pollutants that exist in anionic species are issues of concern in water treatment. Compared to cationic pollutants, the removal of anionic pollutants by adsorption is more difficult because most adsorbents carry predominantly negative charges in neutral and alkaline environments. In this study, a cross-linked chitosan derivative with quaternary ammonium and magnetic properties (QM-chitosan) was prepared and employed to remove chromium (VI) and phosphorus (V) (Cr(VI) and P(V)) from aqueous environments. The QM-chitosan was characterized by Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), energy dispersive X-ray (SEM-EDX) and zeta potential. Batch experiments show that QM-chitosan can effectively remove Cr(VI) and P(V), and the main mechanism was believed to be electrostatic interaction. A pseudo second-order model was fitted to describe the kinetic processes of Cr(VI) and P(V) removal. The adsorption isotherms of both Cr(VI) and P(V) on the QM-chitosan were well fitted by the Langmuir isotherm equation. The saturated adsorption capacity of P(V) (2.783 mmol/g) was found to be higher than that of Cr(VI) (2.323 mmol/g), resulting from the size of the H(2)PO(4)(-) ions being smaller than that of the HCrO(4)(-) ions. However, the theoretical calculation and experimental results showed that QM-chitosan had a stronger affinity for Cr(VI) than P(V). The adsorption-desorption of the QM-chitosan was evaluated, and high regeneration rates were demonstrated.
存在于阴离子物种中的污染物是水处理中关注的问题。与阳离子污染物相比，吸附去除阴离子污染物更困难，因为大多数吸附剂在中性和碱性环境中主要带负电荷。在这项研究中，制备了一种带有季铵盐和磁性的交联壳聚糖衍生物（QM-壳聚糖），并将其用于从水溶液中去除铬（VI）和磷（V）（Cr(VI) 和 P(V)）。通过傅里叶变换红外光谱（FT-IR）、热重分析（TGA）、能量色散 X 射线（SEM-EDX）和zeta 电位对 QM-壳聚糖进行了表征。批实验表明，QM-壳聚糖可以有效地去除 Cr(VI) 和 P(V)，主要机制被认为是静电相互作用。拟二级动力学模型拟合描述了 Cr(VI) 和 P(V)去除的动力学过程。Cr(VI) 和 P(V)在 QM-壳聚糖上的吸附等温线均很好地符合 Langmuir 等温线方程。发现 P(V)（2.783mmol/g）的饱和吸附容量高于 Cr(VI)（2.323mmol/g），这是因为 H₂PO₄(-)离子的尺寸小于 HCrO₄(-)离子的尺寸。然而，理论计算和实验结果表明，QM-壳聚糖对 Cr(VI)的亲和力强于 P(V)。评估了 QM-壳聚糖的吸附-解吸性能，证明了其具有较高的再生率。
