Maponya Thabiso C, Makgopa Katlego, Somo Thabang R, Modibane Kwena D
Nanotechnology Research Lab, Department of Chemistry, School of Physical and Mineral Sciences, University of Limpopo (Turfloop), Sovenga 0727, Polokwane, South Africa.
Department of Chemistry, Faculty of Science, Tshwane University of Technology (Arcadia Campus), Pretoria 0001, South Africa.
Polymers (Basel). 2022 Sep 1;14(17):3613. doi: 10.3390/polym14173613.
The accumulation of toxic heavy metal ions continues to be a global concern due to their adverse effects on the health of human beings and animals. Adsorption technology has always been a preferred method for the removal of these pollutants from wastewater due to its cost-effectiveness and simplicity. Hence, the development of highly efficient adsorbents as a result of the advent of novel materials with interesting structural properties remains to be the ultimate objective to improve the adsorption efficiencies of this method. As such, advanced materials such as metal-organic frameworks (MOFs) that are highly porous crystalline materials have been explored as potential adsorbents for capturing metal ions. However, due to their diverse structures and tuneable surface functionalities, there is a need to find efficient characterization techniques to study their atomic arrangements for a better understanding of their adsorption capabilities on heavy metal ions. Moreover, the existence of various species of heavy metal ions and their ability to form complexes have triggered the need to qualitatively and quantitatively determine their concentrations in the environment. Hence, it is crucial to employ techniques that can provide insight into the structural arrangements in MOF composites as well as their possible interactions with heavy metal ions, to achieve high removal efficiency and adsorption capacities. Thus, this work provides an extensive review and discussion of various techniques such as X-ray diffraction, Brunauer-Emmett-Teller theory, scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectroscopy, and X-ray photoelectron spectroscopy employed for the characterization of MOF composites before and after their interaction with toxic metal ions. The review further looks into the analytical methods (i.e., inductively coupled plasma mass spectroscopy, ultraviolet-visible spectroscopy, and atomic absorption spectroscopy) used for the quantification of heavy metal ions present in wastewater treatment.
有毒重金属离子的积累因其对人类和动物健康的不利影响,仍然是一个全球关注的问题。吸附技术因其成本效益高和操作简单,一直是从废水中去除这些污染物的首选方法。因此,随着具有有趣结构特性的新型材料的出现,开发高效吸附剂仍然是提高该方法吸附效率的最终目标。因此,诸如金属有机框架(MOF)等具有高度多孔晶体结构的先进材料已被探索作为捕获金属离子的潜在吸附剂。然而,由于它们多样的结构和可调节的表面功能,需要找到有效的表征技术来研究它们的原子排列,以便更好地理解它们对重金属离子的吸附能力。此外,各种重金属离子的存在及其形成络合物的能力引发了定性和定量测定它们在环境中浓度的需求。因此,采用能够深入了解MOF复合材料的结构排列及其与重金属离子可能的相互作用的技术,以实现高去除效率和吸附容量至关重要。因此,这项工作对各种技术进行了广泛的综述和讨论,如X射线衍射、布鲁诺尔-埃米特-泰勒理论、扫描电子显微镜和透射电子显微镜结合能量色散光谱,以及用于表征MOF复合材料与有毒金属离子相互作用前后的X射线光电子能谱。该综述还进一步探讨了用于量化废水处理中存在的重金属离子的分析方法(即电感耦合等离子体质谱、紫外可见光谱和原子吸收光谱)。