Mechanisms of lead adsorption on chitosan/PVA hydrogel beads
Mechanisms of lead adsorption on chitosan/PVA hydrogel beads
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DOI：
10.1021/la025917l
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发表时间：
2002-12-10
期刊：
影响因子：
3.9
通讯作者：
Bai, RB
中科院分区：
文献类型：
--
作者：
Jin, L;Bai, RB
在不同pH值（2 ~ 7.6）下，研究了壳聚糖/聚乙烯醇（PVA）水凝胶小球对水溶液中铅的吸附性能。铅吸附壳聚糖/聚乙烯醇珠被认为是强烈的pH值依赖性，并显示在pH值约4和pH值约6.4的最小值的最大吸收能力。Zeta电位研究表明，壳聚糖/PVA微球在pH 6.3时具有正的Zeta电位< 6.3 and negative zeta-potentials at pH >。因此，吸附发生，即使铅和壳聚糖/PVA珠之间的相互作用是静电排斥在pH < 6.3。络合，离子交换，和静电相互作用都被认为是发挥作用，在壳聚糖/PVA珠铅吸附，但这些机制的相对重要性随溶液的pH值而变化。傅立叶变换红外光谱和X射线光电子能谱表明，在所研究的pH范围内，壳聚糖对铅的吸附主要是通过与壳聚糖中的N原子相互作用实现的。
Removal of lead from aqueous solution with chitosan/PVA (poly(vinyl alcohol)) hydrogel beads was studied in batch adsorption experiments at various solution pH values (2-7.6). Lead adsorption on chitosan/PVA beads was found to be strongly pH-dependent and displayed a maximum uptake capacity at pH around 4 and a minimum at pH about 6.4. zeta-Potential study indicated that chitosan/PVA beads possessed positive zeta-potentials at pH < 6.3 and negative zeta-potentials at pH > 6.3. Hence, adsorption occurred even though the interaction between lead and chitosan/PVA beads was electrostatically repulsive at pH < 6.3. Complexation, ion exchange, and electrostatic interaction are all believed to play a role in lead adsorption on chitosan/PVA beads, but the relative importance of each of these mechanisms varies with solution pH values. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy spectra suggested that lead adsorption was mainly through interactions with the N atoms in chitosan in the pH range studied.