Ccamerccoa M Huanca, Falcon N L Tapia, Félix L León, Pacheco-Salazar D G, Aragón F F H, Coaquira J A H, Garnier Jéremie, Vera-Gonzales C
Departamento de Química, Universidad Nacional de San Agustín de Arequipa. Laboratorio LAPCI-Nano, Independencia s/n, Arequipa, Perú.
Laboratorio de Películas Delgadas, Universidad Nacional de San Agustín de Arequipa, Escuela Profesional de Física, Av. Independencia s/n, Arequipa, Perú.
J Environ Health Sci Eng. 2022 Sep 14;20(2):849-860. doi: 10.1007/s40201-022-00825-y. eCollection 2022 Dec.
Water is an essential compound on earth and necessary for life. The presence of highly toxic contaminants such as arsenic and others, in many cases, represents one of the biggest problems facing the earth´s population. Treatment of contaminated water with magnetite (FeO) nanoparticles (NPs) can play a crucial role in arsenic removal. In this report, we demonstrate arsenic removal from an aqueous solution and natural water taken from the Peruvian river (Tambo River in Arequipa, Peru) using magnetite NPs synthesized by the coprecipitation method. XRD data analysis of FeO NPs revealed the formation of the cubic-spinel phase of magnetite with an average crystallite size of ~ 13 nm, which is found in good agreement with the physical size assessed from TEM image analysis. Magnetic results evidence that our NPs show a superparamagnetic-like behavior with a thermal relaxation of magnetic moments mediated by strong particle-particle interactions. FTIR absorption band shows the interactions between arsenate anions and Fe-O and Fe-OH groups through a complex mechanism. The experimental results showed that arsenic adsorption is fast during the first 10 min; while the equilibrium is reached within 60 min, providing an arsenic removal efficiency of ~ 97%. Adsorption kinetics is well modeled using the pseudo-second-order kinetic equation, suggesting that the adsorption process is related to the chemisorption model. According to Langmuir's model, the maximum arsenic adsorption capacity of 81.04 mg·g at pH = 2.5 was estimated, which describes the adsorption process as being monolayer, However, our results suggest that multilayer adsorption can be produced after monolayer saturation in agreement with the Freundlich model. This finding was corroborated by the Sips model, which showed a good correlation to the experimental data. Tests using natural water taken from Tambo River indicate a significant reduction of arsenic concentration from 356 µg L to 7.38 µg L, the latter is below the limit imposed by World Health Organization (10 µg L), suggesting that magnetite NPs show great potential for the arsenic removal.
水是地球上一种必不可少的化合物，是生命所必需的。在许多情况下，诸如砷等剧毒污染物的存在是地球人口面临的最大问题之一。用磁铁矿（FeO）纳米颗粒（NPs）处理受污染的水在去除砷方面可以发挥关键作用。在本报告中，我们展示了使用通过共沉淀法合成的磁铁矿纳米颗粒从水溶液和取自秘鲁河流（秘鲁阿雷基帕的坦博河）的天然水中去除砷的过程。对FeO纳米颗粒的XRD数据分析表明形成了磁铁矿的立方尖晶石相，平均晶粒尺寸约为13nm，这与通过TEM图像分析评估的物理尺寸高度吻合。磁性结果证明，我们的纳米颗粒表现出类似超顺磁性的行为，其磁矩的热弛豫由强烈的颗粒间相互作用介导。FTIR吸收带通过复杂机制显示了砷酸根阴离子与Fe-O和Fe-OH基团之间的相互作用。实验结果表明，砷的吸附在前10分钟内很快；而在60分钟内达到平衡，砷的去除效率约为97%。吸附动力学使用伪二级动力学方程进行了很好的建模，表明吸附过程与化学吸附模型有关。根据朗缪尔模型，估计在pH = 2.5时最大砷吸附容量为81.04mg·g，该模型将吸附过程描述为单层吸附，然而，我们的结果表明，与弗伦德利希模型一致，单层饱和后会产生多层吸附。这一发现得到了西普斯模型的证实，该模型与实验数据显示出良好的相关性。使用取自坦博河的天然水进行的测试表明，砷浓度从356μg/L显著降低至7.38μg/L，后者低于世界卫生组织规定的限值（10μg/L），这表明磁铁矿纳米颗粒在去除砷方面具有巨大潜力。
