Departamento de Ingeniería Química y Textil, Facultad de Ciencias Quimicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain.
Departamento de Ingeniería Química y Textil, Facultad de Ciencias Quimicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
J Environ Manage. 2021 May 1;285:112155. doi: 10.1016/j.jenvman.2021.112155. Epub 2021 Feb 27.
Fenton reaction is an oxidation process of interest in wastewater treatment because of its ability to degrade organic compounds. Iron-based magnetic particles can be a very useful catalyst when using heterogeneous Fenton process. The major problem of this heterogeneous process is the saturation of the Fe on the surface, which limits the process. In this study, the possibility of using magnetite particles as a substrate is presented, increasing its degradation efficiency by Fenton reaction through a regeneration process that achieves the electronic reduction of its surface using reducing agents. The results indicate that the regeneration process is quite effective, increasing the efficiency of the degradation of Methylene Blue up to 99%. The concentration of magnetite is the most influential factor in the efficiency of the reaction, while the regeneration time and the concentration of reducing agent do not significantly affect the results considering the range used. The presence of mechanical stirring may adversely affect the reaction in the long term. Increasing the oxidant agent concentration reduces the initial speed of the reaction but not the long-term efficiency. The use of hydrazine in this process allows the successive reuse of these particles maintaining a high percentage of elimination of methylene blue, above 70% even after 10 uses, compared to an elimination below 20% for particles not regenerated after the second use and for particles regenerated with ascorbic acid after the eighth use.
芬顿反应是一种废水处理中很有前途的氧化过程，因为它能够降解有机化合物。在使用多相芬顿法时，基于铁的磁性颗粒可以作为一种非常有用的催化剂。这个多相过程的主要问题是表面的 Fe 达到饱和，这限制了该过程。在这项研究中，提出了使用磁铁矿颗粒作为基质的可能性，通过再生过程来提高芬顿反应的降解效率，该过程使用还原剂实现表面的电子还原。结果表明，再生过程非常有效，将亚甲蓝的降解效率提高了 99%。磁铁矿的浓度是反应效率的最主要影响因素，而在使用的范围内，再生时间和还原剂浓度对结果没有显著影响。机械搅拌的存在可能会对长期反应产生不利影响。增加氧化剂浓度会降低反应的初始速度，但不会降低长期效率。在该过程中使用水合肼允许这些颗粒连续重复使用，保持亚甲基蓝的高去除率，即使在 10 次使用后仍高于 70%，而在第二次使用后未再生的颗粒的去除率低于 20%，在第八次使用后用抗坏血酸再生的颗粒的去除率也低于 20%。
