Simonič Marjana, Fras Zemljič Lidija
Laboratory for Water Biophysics and Membrane Processes, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia.
Laboratory for Characterization and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia.
Materials (Basel). 2020 Jul 18;13(14):3208. doi: 10.3390/ma13143208.
In this paper, the aim of the research was to obtain a highly efficient wool-based sorbent for the removal of zinc Zn(II) from wastewater. To increase the functional groups for metal binding, the wool was functionalized with chitosan. Chitosan has amino groups through which metals can be complexed easily to chelates. The physical and chemical modification of chitosan on wool was performed to analyze the influence of the coating bond on the final ability of the wool to remove metals. The presence of functional chitosan groups onto wool after adsorption was verified by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT-IR) spectra. The effective binding of chitosan to wool was also determined by potentiometric and polyelectrolyte titration methods. The latter titration was used to analyze the chitosan desorption. The main part of the study was the sorption of Zn(II) on natural and functionalized wool. The influence was investigated as a function of contact time, pH, metal ion concentration and temperature on the sorption process. The absorbent with the highest concentration of protonated amino groups (607.7 mmol/kg) and responding sorption capacity of 1.52 mg/g was obtained with wool physically modified by a macromolecular chitosan solution (1%) at pH = 7. Adsorption of Zn(II) onto pristine and modified wool corresponded to pseudo-second order kinetics ( > 0.9884). The Langmuir model was found to be more suitable ( > 0.9866) in comparison to the Freundlich model. The Zn(II) sorption process was spontaneous (∆ < 0) and exothermic (∆ < 0). The results found in this study are significant for escalating the possible use of wool modified with polysaccharide coatings as a sustainable source to improve or increase the metal sorption activity of wool.
在本文中，研究目的是获得一种高效的羊毛基吸附剂，用于从废水中去除锌离子（Zn(II)）。为增加用于金属结合的官能团，羊毛用壳聚糖进行了功能化处理。壳聚糖含有氨基，金属可通过这些氨基轻松络合形成螯合物。对羊毛上的壳聚糖进行物理和化学改性，以分析涂层键合对羊毛最终去除金属能力的影响。吸附后通过衰减全反射傅里叶变换红外光谱（ATR-FT-IR）光谱验证羊毛上功能性壳聚糖基团的存在。还通过电位滴定法和聚电解质滴定法确定壳聚糖与羊毛的有效结合。后一种滴定法用于分析壳聚糖的解吸。研究的主要部分是Zn(II)在天然羊毛和功能化羊毛上的吸附。研究了接触时间、pH值、金属离子浓度和温度对吸附过程的影响。用1%的大分子壳聚糖溶液在pH = 7时对羊毛进行物理改性，得到了质子化氨基浓度最高（607.7 mmol/kg）且吸附容量为1.52 mg/g的吸附剂。Zn(II)在原始羊毛和改性羊毛上的吸附符合准二级动力学（> 0.9884）。与弗伦德利希模型相比，发现朗缪尔模型更合适（> 0.9866）。Zn(II)的吸附过程是自发的（∆ < 0）且放热的（∆ < 0）。本研究结果对于扩大用多糖涂层改性的羊毛作为可持续来源以提高或增强羊毛金属吸附活性的可能用途具有重要意义。
