Vlachou Irene, Bokias Georgios
Department of Chemistry, University of Patras, GR-26504 Patras, Greece.
Materials (Basel). 2023 Feb 25;16(5):1926. doi: 10.3390/ma16051926.
Rapid industrialization has led to huge amounts of organic pollutants and toxic heavy metals into aquatic environment. Among the different strategies explored, adsorption remains until the most convenient process for water remediation. In the present work, novel cross-linked chitosan-based membranes were elaborated as potential adsorbents of Cu ions, using as cross-linking agent a random water-soluble copolymer P(DMAM-co-GMA) of glycidyl methacrylate (GMA) and N,N-dimethylacrylamide (DMAM). Cross-linked polymeric membranes were prepared through casting aqueous solutions of mixtures of P(DMAM-co-GMA) and chitosan hydrochloride, followed by thermal treatment at 120 °C. After deprotonation, the membranes were further explored as potential adsorbents of Cu ions from aqueous CuSO solution. The successful complexation of copper ions with unprotonated chitosan was verified visually through the color change of the membranes and quantified through UV-vis spectroscopy. Cross-linked membranes based on unprotonated chitosan adsorb Cu ions efficiently and decrease the concentration of Cu ions in water to a few ppm. In addition, they can act as simple visual sensors for the detection of Cu ions at low concentrations (~0.2 mM). The adsorption kinetics were well-described by a pseudo-second order and intraparticle diffusion model, while the adsorption isotherms followed the Langmuir model, revealing maximum adsorption capacities in the range of 66-130 mg/g. Finally, it was shown that the membranes can be effectively regenerated using aqueous HSO solution and reused.
快速工业化已导致大量有机污染物和有毒重金属进入水生环境。在探索的不同策略中，吸附仍然是水修复最便捷的过程。在本工作中，使用甲基丙烯酸缩水甘油酯（GMA）和N，N - 二甲基丙烯酰胺（DMAM）的无规水溶性共聚物P（DMAM - co - GMA）作为交联剂，制备了新型交联壳聚糖基膜作为铜离子的潜在吸附剂。通过浇铸P（DMAM - co - GMA）和壳聚糖盐酸盐混合物的水溶液，然后在120℃下进行热处理来制备交联聚合物膜。去质子化后，进一步探索这些膜作为从硫酸铜水溶液中吸附铜离子的潜在吸附剂。通过膜的颜色变化直观地验证了铜离子与未质子化壳聚糖的成功络合，并通过紫外 - 可见光谱进行了定量。基于未质子化壳聚糖的交联膜能有效吸附铜离子，并将水中铜离子浓度降低至几ppm。此外，它们可作为简单的视觉传感器用于检测低浓度（约0.2 mM）的铜离子。吸附动力学可用伪二级和颗粒内扩散模型很好地描述，而吸附等温线遵循朗缪尔模型，显示最大吸附容量在66 - 130 mg/g范围内。最后，结果表明这些膜可用硫酸水溶液有效再生并重复使用。
