Zhu Xi, Guo Yong, Zheng Baozhan
College of Chemistry, Sichuan University, Chengdu 610065, China.
Molecules. 2024 Aug 9;29(16):3768. doi: 10.3390/molecules29163768.
A novel graphene-based composite, 5-methyl-1,3,4-thiadiazol-2-amine (MTA) covalently functionalized graphene oxide (GO-MTA), was rationally developed and used for the selective sorption of Ga from aqueous solutions, showing a higher adsorption capacity (48.20 mg g) toward Ga than In (15.41 mg g) and Sc (0 mg g). The adsorption experiment's parameters, such as the contact time, temperature, initial Ga concentration, solution pH, and desorption solvent, were investigated. Under optimized conditions, the GO-MTA composite displayed the highest adsorption capacity of 55.6 mg g toward Ga. Moreover, a possible adsorption mechanism was proposed using various characterization methods, including scanning electron microscopy (SEM) equipped with X-ray energy-dispersive spectroscopy (EDS), elemental mapping analysis, Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Ga adsorption with the GO-MTA composite could be better described by the linear pseudo-second-order kinetic model ( = 0.962), suggesting that the rate-limiting step may be chemical sorption or chemisorption through the sharing or exchange of electrons between the adsorbent and the adsorbate. Importantly, the calculated value (55.066 mg g) is closer to the experimental result (55.60 mg g). The well-fitted linear Langmuir isothermal model ( = 0.9720.997) confirmed that an interfacial monolayer and cooperative adsorption occur on a heterogeneous surface. The results showed that the GO-MTA composite might be a potential adsorbent for the enrichment and/or separation of Ga at low or ultra-low concentrations in aqueous solutions.
一种新型的基于石墨烯的复合材料，即5-甲基-1,3,4-噻二唑-2-胺（MTA）共价功能化氧化石墨烯（GO-MTA），被合理开发并用于从水溶液中选择性吸附镓，其对镓的吸附容量（48.20 mg/g）高于铟（15.41 mg/g）和钪（0 mg/g）。研究了吸附实验的参数，如接触时间、温度、初始镓浓度、溶液pH值和解吸溶剂。在优化条件下，GO-MTA复合材料对镓的吸附容量最高可达55.6 mg/g。此外，使用多种表征方法提出了一种可能的吸附机制，包括配备X射线能量色散光谱（EDS）的扫描电子显微镜（SEM）、元素映射分析、傅里叶变换红外（FT-IR）光谱和X射线光电子能谱（XPS）。GO-MTA复合材料对镓的吸附可以用线性准二级动力学模型（ = 0.962）更好地描述，这表明限速步骤可能是化学吸附或通过吸附剂与吸附质之间电子的共享或交换进行的化学吸着。重要的是，计算得到的 值（55.066 mg/g）更接近实验结果（55.60 mg/g）。拟合良好的线性朗缪尔等温模型（ = 0.9720.997）证实了在异质表面上发生界面单层和协同吸附。结果表明，GO-MTA复合材料可能是一种潜在的吸附剂，用于在水溶液中低浓度或超低浓度下富集和/或分离镓。
