Ciocărlie Loredana, Negrea Adina, Ciopec Mihaela, Duteanu Narcis, Negrea Petru, Svera M Ianăși Paula, Ianăşi Cătălin
Faculty of Chemical Engibeering, Biotechnologies and Environmental Protection, Polytechnic University of Timişoara, Victoriei Square, No. 2, 300006 Timisoara, Romania.
National Institute for Research and Development in Electrochemistry and Condensed Matter, 144th Dr. A.P. Podeanu Street, 300569 Timisoara, Romania.
Materials (Basel). 2024 Nov 23;17(23):5740. doi: 10.3390/ma17235740.
The European Union regards gallium as a crucial element. Because of that, the retrieval of gallium ions from secondary sources through diverse methodologies is of the utmost significance in an actual economical context. The primary goal of this study was to explore the viability of MgFeO spinel as an adsorbent material for Ga(III) ions recovery from aqueous solutions. A spinel adsorbent material was synthesised by using the sol-gel synthesis method. After preparation, the obtained spinel was subjected to a thermal treatment, which resulted in modifications of its crystalline structure and morphology, in concordance with the calcination temperatures. Specifically, two distinct temperatures of 260 and 650 °C were utilised in the process, which was conducted in air. The second objective was represented by the physicochemical characterisation of the newly prepared adsorbent material by using various analytical techniques, e.g., Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and magnetic measurements. The optimal conditions for Ga(III) adsorption were established (S:L ratio, solution pH, contact time, temperature, initial Ga(III) concentration). Simultaneously, the obtained experimental data were modelled to prove the fact that the pseudo-second-order model explained the studied kinetics process and established its mechanism. Intraparticle diffusion was also studied to highlight the rate-determined step during the Ga(III) adsorption process. The equilibrium of the process was also studied, establishing that the Sips isotherm fitted the experimental data best, with a correlation coefficient R~1, indicating that the studied adsorption process was homogeneous, the maximum adsorption capacity of spinel being 24.7 mg Ga (III)/g MgFeO. Thermodynamic parameters, involving ΔG°, ΔH° and ΔS°, were also calculated; negative values of ΔG° indicated that the adsorption was spontaneous. ΔH° proved to be endothermic, and the calculated ΔS° values being positive confirmed the fact that the process was spontaneous.
欧盟将镓视为关键元素。因此，在实际经济背景下，通过多种方法从二次资源中回收镓离子具有极其重要的意义。本研究的主要目标是探索MgFeO尖晶石作为从水溶液中回收Ga(III)离子的吸附材料的可行性。采用溶胶-凝胶合成法合成了一种尖晶石吸附材料。制备后，对所得尖晶石进行热处理，这导致其晶体结构和形态根据煅烧温度发生改变。具体而言，该过程在空气中进行，使用了260和650℃这两个不同的温度。第二个目标是通过使用各种分析技术，如傅里叶变换红外光谱(FT-IR)、原子力显微镜(AFM)和磁性测量，对新制备的吸附材料进行物理化学表征。确定了Ga(III)吸附的最佳条件（固液比、溶液pH值、接触时间、温度、初始Ga(III)浓度）。同时，对获得的实验数据进行建模，以证明伪二级模型解释了所研究的动力学过程并确定了其机制。还研究了颗粒内扩散，以突出Ga(III)吸附过程中的速率决定步骤。还研究了该过程的平衡，确定Sips等温线最符合实验数据，相关系数R~1，表明所研究的吸附过程是均匀的，尖晶石的最大吸附容量为24.7 mg Ga(III)/g MgFeO。还计算了热力学参数，包括ΔG°、ΔH°和ΔS°；ΔG°的负值表明吸附是自发的。ΔH°被证明是吸热的，计算得到的ΔS°值为正值证实了该过程是自发的这一事实。
