Full text
| |
| Author(s): |
Leticia Mirella da Silva
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT) |
| Defense date: | 2024-03-15 |
| Examining board members: |
Artur de Jesus Motheo;
Ricardo Andrés Salazar González;
Fabiola Martínez Navarro;
Manuel Andrés Rodrigo Rodrigo;
Elisama Vieira dos Santos
|
| Advisor: | Artur de Jesus Motheo |
| Abstract | |
Soil and water pollution by pesticides can occur in different ways, either through improper use or accidental spillage into the environment. Several studies are dedicated to the recovery of these natural resources. Methomyl, a common pesticide of the carbamate class in Brazil, used to control insects, can cause serious problems, like endocrine interference in animals and humans. Because of this, it is necessary to recover the affected medium and make it free of dissolved organics. This thesis addressed different electrochemical treatments to remove carbamates from water and soil. Initially, tests were carried out with a model molecule (methyl paraben-MeP) to understand the functioning of an electrochemical reactor. The study included the analysis of surfactants in the removal of MeP in an aqueous medium. Then, methomyl treatments in aqueous medium and soil were conducted using 3D-printed flow reactors for continuous generation of HClO3, H2O2, ClO2 and O3. During the study of MeP removal, the influence of variables such as current density, pH, and surfactant concentration was investigated. It was observed that high current densities and basic pH favor MeP degradation. High concentrations of surfactants can reduce the efficiency of the MeP oxidation process. The cationic surfactant showed a higher interfering effect. When treating methomyl in an acidic medium, persulfate ions favored its removal, with the concentration modifying the kinetics. In the treatment with chlorine dioxide in a continuous flow, a flow of ClO2 was produced that was efficient in the oxidation of methomyl. However, an electrochemical reactor with an MMO anode degraded the methomyl with a greater energy consumption. The continuous use of ozone showed efficiency in the oxidation of methomyl when activated with UV light and H2O2. In treating synthetically contaminated soil, continued use of chlorine dioxide resulted in the complete depletion of methomyl in the simulated soil wash solution. However, direct dosing into the soil had reduced performance, highlighting the importance of optimizing these parameters. Thus, this Thesis demonstrates the feasibility of remediating wastewater and soil through direct electrochemical technologies or those mediated by gaseous oxidants. (AU) | |
| FAPESP's process: | 18/26475-9 - Evaluation and application of electrodes of oxide mixtures and boron doped diamond for the degradation of organic compounds with activity of endocrine interference |
| Grantee: | Leticia Mirella da Silva |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |