Department of Civil and Environmental Engineering, National University of Singapore, 117576 Singapore, Singapore.
Carbohydr Polym. 2013 Feb 15;92(2):2181-6. doi: 10.1016/j.carbpol.2012.12.009. Epub 2012 Dec 12.
Novel poly(vinyl alcohol)/citric acid/chitosan (PVA/CA/CHT, PCC) beads were prepared as an adsorbent for the removal of trivalent chromium (Cr(3+)) in aqueous solutions. PCC beads with different mass ratios (I, II, III, IV, V, ad VI) between PVA/CA/CHT were evaluated for the removal of Cr(3+) ions to find an optimal stoichiometry of PCC beads, which indicated that the PCC bead (II) with the PVA/CA/CHT mass ratio of 1/5/1 showed the highest adsorption for Cr(3+) ions. The surface characteristics of PCC beads (II) were determined by scanning electron microscopy using a field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FTIR). The results obtained in this study implied that PCC bead (II) had an obviously rough and folded structure, and its spectrum manifested significant changes compared to those of PVA, CA and CHT. The sorption experiments were conducted to evaluate the performance of PCC beads (II) to adsorb Cr(3+) ions in aqueous solutions. Results indicated that the Cr(3+) ion sorption onto PCC beads (II) was highly pH-dependent with the maximum uptake at pH 6.0. The sorption kinetics data were well fitted by the pseudo-second-order equation with high regression coefficients. Sorption isotherm of PCC beads (II) was well described by Langmuir equation, with a maximum sorption at 41.5mg Cr/g PCC beads (II). Desorption studies were also carried out by the repeated sorption/desorption experiments. The high efficiency and reusability of PCC beads (II) make them an attractive sorbent for the removal of Cr(3+) and possibly other metals in aqueous solutions.
新型聚乙烯醇/柠檬酸/壳聚糖（PVA/CA/CHT，PCC）珠粒作为一种吸附剂，用于去除水溶液中的三价铬（Cr(3+)）。评估了具有不同 PVA/CA/CHT 质量比（I、II、III、IV、V 和 VI）的 PCC 珠粒对 Cr(3+)离子的去除效果，以找到 PCC 珠粒的最佳化学计量比，结果表明，PVA/CA/CHT 质量比为 1/5/1 的 PCC 珠粒（II）对 Cr(3+)离子的吸附效果最佳。通过场发射扫描电子显微镜（FESEM）和傅里叶变换红外光谱（FTIR）对 PCC 珠粒（II）的表面特性进行了测定。研究结果表明，PCC 珠粒（II）具有明显的粗糙和折叠结构，与 PVA、CA 和 CHT 相比，其光谱发生了显著变化。进行了吸附实验，以评估 PCC 珠粒（II）在水溶液中吸附 Cr(3+)离子的性能。结果表明，Cr(3+)离子在 PCC 珠粒（II）上的吸附高度依赖于 pH 值，在 pH 值为 6.0 时吸附量最大。吸附动力学数据与准二级方程拟合良好，具有较高的回归系数。PCC 珠粒（II）的吸附等温线很好地符合 Langmuir 方程，最大吸附量为 41.5mg Cr/g PCC 珠粒（II）。还通过重复吸附/解吸实验进行了脱附研究。PCC 珠粒（II）的高效率和可重复使用性使其成为去除水溶液中 Cr(3+)和其他金属的一种有吸引力的吸附剂。
