Bulin Chaoke, Xiong Qianhui, Zheng Rongxiang, Li Chenna, Ma Yuelong, Guo Ting
College of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, PR China.
College of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Feb 15;307:123645. doi: 10.1016/j.saa.2023.123645. Epub 2023 Nov 13.
Phytic acid modified graphene oxide (PGO) has encouraging prospect in environmental application. Herein, PGO was fabricated with a simple hydrothermal method and used as adsorbent to remove methyl blue (MB). Elaborate inspection based on the hard-soft acid-base (HSAB) principle, spectroscopic characterization, as well as batch adsorption and fitting were conducted to unravel the adsorption mechanism. Results show, PGO efficiently adsorbs 89.08 mg·g of MB in 22 min. HSAB principle proposes, high electron transfer (ΔN) and energy lowering (ΔE) induce covalent bond (chemical interaction), while low ΔN and ΔE induce electrostatic effect (physical interaction). Accordingly, both the first and second strongest interaction occurs between PA moiety and MB: π electrons of MB flows towards O atom in OH and O(-O-) of PA, respectively. Yet the third strongest interaction happens between GO moiety and MB: electron of O atom in OH group of GO flows towards N atom of MB. Above top three interactions are characterized by prominent ΔN and ΔE implying the formation of covalent bond. However, other interactions yield low ΔN and ΔE, suggesting the presence of electrostatic effect. HSAB principle conclusion was substantiated by FTIR and UV-Vis analyses. These findings confirm that PA modification enhances the adsorption affinity of graphene oxide. Thereby, chemical adsorption induced by physical interaction is proposed. This work may inspire the design of efficient adsorbent based on PGO framework for environmental restoration.
植酸修饰的氧化石墨烯（PGO）在环境应用中具有广阔前景。在此，采用简单水热法制备了PGO，并将其用作吸附剂去除亚甲基蓝（MB）。基于软硬酸碱（HSAB）原理进行了详细研究、光谱表征以及批量吸附和拟合，以揭示吸附机理。结果表明，PGO在22分钟内可有效吸附89.08 mg·g的MB。HSAB原理表明，高电子转移（ΔN）和能量降低（ΔE）会诱导共价键（化学相互作用），而低ΔN和ΔE会诱导静电效应（物理相互作用）。因此，PA部分与MB之间发生了最强的第一和第二相互作用：MB的π电子分别流向PA的OH中的O原子和PA的O（-O-）。然而，GO部分与MB之间发生了第三强的相互作用：GO的OH基团中的O原子的电子流向MB的N原子。上述前三种相互作用具有显著的ΔN和ΔE，这意味着共价键的形成。然而，其他相互作用产生的ΔN和ΔE较低，表明存在静电效应。FTIR和UV-Vis分析证实了HSAB原理的结论。这些发现证实了PA修饰增强了氧化石墨烯的吸附亲和力。因此，提出了由物理相互作用诱导的化学吸附。这项工作可能会激发基于PGO框架设计用于环境修复的高效吸附剂。
