Synthesis of layered double hydroxides by hydrosolvothermal method for the degradation of antibiotics present in wastewater

• Grant number: 23/16703-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: January 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Raquel Fernandes Pupo Nogueira
• Grantee: João Maurício Beghetto Tomaz de Aquino
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

In recent decades, pharmaceuticals have emerged as a new class of environmental contaminants. Considering the inefficiency of conventional treatments in sewage treatment plants combined with the lack of current legislation to control the removal of drugs, the development of strategies and methods for their removal becomes essential. The Layered Double Hydroxides (LDH) have gained recent research interest as catalyst in environmental remediation due to its multifunctional properties. Among the most interesting properties, the high surface area, flexibility for incorporation of cations of different elements and valences into the same structure with low leaching, considerable chemical and thermal stability, low toxicity, low production cost, ease of synthesis and application under neutral conditions. To take advantage of the excellent characteristics of these materials and improve their catalytic properties, some treatments on LDHs have been carried out, such as calcination. Nonetheless, it has been reported that in this process, the lamellar structure of the material is destroyed due to elimination of water molecules from the interlayer space, dehydroxylation, as well as the loss of interlayer anion. Therefore, new treatment methods for LDHs for applications in catalysis are interesting to investigate. Hydrosolvothermal treatment in LDHs for applications in heterogeneous Fenton process has not yet been studied. This treatment can bring several benefits such as phase permanence of the double hydroxide structure, increase the ease of exchange between layered anions as well as crystallinity, and improve the catalytic properties of these materials. In summary, this study aims to synthesize LDHs of the type CuMgFe-CO3 and apply hydrosolvothermal treatment in the presence of excess borate to promote the exchange of CO32- with B(OH)4- and improve the catalytic performance of these materials, since studies report the difficulty of borate intercalation in HDLs and the favorable generation of reactive oxygen species with the borate ion in the inter layered space, and consequently increasing the efficiency of contaminant degradation. The catalytic activity of the obtained material will be evaluated in the simultaneous removal of the drugs sulfadiazine and sulfamethazine, present in effluents by the heterogeneous Fenton process.