Postgraduate Program in Environmental Science, Santa Catarina State University, Av. Luiz de Camões, 2090, Conta Dinheiro,, Lages, SC, CEP: 88520-000, Brazil.
Department of Environmental and Sanitary Engineering, Santa Catarina State University, Av. Luiz de Camões, 2090, Conta Dinheiro,, Lages, SC, CEP: 88520-000, Brazil.
Environ Sci Pollut Res Int. 2019 Oct;26(28):28481-28489. doi: 10.1007/s11356-018-3208-3. Epub 2018 Sep 18.
The aim of this work was to study the adsorption and removal of chromium (VI) ions contained in aqueous solutions using a chitosan-based hydrogel synthesized via chemical crosslinking of radical chitosan, polyacrylic acid, and N,N'-methylenebisacrylamide. Fourier-transform infrared spectroscopy confirmed the hydrogel synthesis and presence of reactive functional groups for the adsorption of chromium (VI) ions. The chromium (VI) adsorption mechanism was evaluated using non-linear Langmuir, Freundlich, Redlich-Peterson, and Sips isotherms, with the best fit found by the non-linear Redlich-Peterson isotherm. The maximum chromium (VI) adsorption capacities of the chitosan-based hydrogel were 73.14 and 93.03 mg metal per g dried hydrogel, according to the non-linear Langmuir and Sips isotherm models, respectively. The best kinetic fit was found with the pseudo-nth order kinetic model. The chromium (VI) removal percentage at pH 4.5 and 100 mg L initial metal concentration was 94.72%. The results obtained in this contribution can be useful for future works involving scale-up of a water and wastewater treatment method from a pilot plant to full-scale plant.
本工作旨在研究通过自由基壳聚糖、聚丙烯酸和 N,N'-亚甲基双丙烯酰胺的化学交联合成的壳聚糖基水凝胶对水溶液中所含六价铬离子的吸附和去除。傅里叶变换红外光谱证实了水凝胶的合成以及存在用于吸附六价铬离子的反应性官能团。通过非线性 Langmuir、Freundlich、Redlich-Peterson 和 Sips 等温线评估了六价铬离子的吸附机制，其中非线性 Redlich-Peterson 等温线的拟合效果最佳。根据非线性 Langmuir 和 Sips 等温线模型，壳聚糖基水凝胶的最大六价铬吸附容量分别为 73.14 和 93.03 mg 金属/g 干水凝胶。假一级动力学模型对动力学拟合效果最佳。在初始金属浓度为 pH 4.5 和 100 mg/L 的条件下，六价铬的去除率为 94.72%。本工作的研究结果可为从中试规模扩大到全规模工厂的水和废水处理方法的未来工作提供参考。
