PDF(Pubmed)
Abstract：
Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.
摘要：
水污染是一项重大的环境挑战。由于常规污水处理厂降解许多有机复杂化合物的效率低下，这些顽固的污染物最终进入河流，湖泊,海洋和其他水体，影响环境和人类健康。半导体光催化被认为是传统方法的有效补充，并为此目的广泛探索了各种纳米材料的使用，特别注重改善他们在可见光下的活动。这项工作的重点是通过溶胶-凝胶和溶剂热合成方法开发磁性和光敏锌/镁混合铁氧体（Zn0.5Mg0.5Fe2O4），这是用于合成铁氧体纳米颗粒的两种最重要和最有效的方法。通过溶胶-凝胶法合成的纳米颗粒（NP）的平均尺寸为14.7nm，而溶剂热法合成的平均粒径为17.4nm。这两种类型都具有主要的立方结构，并表现出超顺磁性行为，达到60.2emug-1的磁化强度饱和值。由于电子/空穴的高复合率，这是铁氧体的固有特征，用银进行表面官能化以增强电荷分离。结果证明了银的吸附和沉积的强烈影响。在合成过程中进行了几个优化步骤，让我们创造出高效的催化剂，通过使用溶胶-凝胶和溶剂热法获得的NP，几乎完全去除染料孔雀石绿，达到95.0％（在0.091min-1的速率常数下）和87.6％（在0.017min-1的速率常数下），分别。对于通过溶胶-凝胶制备的纳米颗粒，黑暗中的吸附占染料去除率的89.2％，对于通过溶剂热法获得的纳米颗粒，则占染料去除率的82.8％。这些结果使得混合锌/镁铁氧体在使用可见光的废水光修复中的潜在工业应用非常有前途。
