Facile synthesis of Fe3O4-SiO2-EN@Zn-Al layered double hydroxide nanocomposites for degradation of amoxicillin under solar, visible and UV lights

Abstract

Antibiotics, categorized as emerging pollutants, present environmental challenges owing to their harmful and mutation-inducing properties, which hinder their removal. This study seeks to produce Fe₃O₄-SiO₂-EN@Zn-Al layered double hydroxide (FSEZAL) nanocomposites for effectively degrading amoxicillin (AMX) through photocatalysis. The target nanocomposite was prepared using a sol–gel method and subsequently characterized in detail using SEM, XRD, FTIR, BET, PL, and VSM techniques. In this study, scavenger results showed that OH and O₂⁻ are both responsible for the AMX degradation. This study also showed that the energy consumed by visible light and UV light during 10–60 min was equal to 44.3 kWh/m³ to 18.5 and 10 to 20.6 kWh/m³, respectively. The reaction rate constant for the photocatalytic process with Fe₃O₄ and SiO₂ nanoparticles, Fe₃O₄-SiO₂-EN, and FSEZAL nanocomposite was 0.0045, 0.0059, 0.0084, and 0.116 1/min, respectively. Also, the half-life constant for nanocomposite was equal to 5.97 min. Ecotoxicity tests were performed using Daphnia magna, and the findings showed a significant reduction in the toxicity of AMX solution. In this study, three types of light were used, and the complete removal of AMX with UV and visible light required 40 min and 60 min, respectively. Also, using sunlight, 87.1 % of AMX was removed within one hour. The reaction rate constants for photocatalytic reactions with UV, visible, and solar lights were 0.116, 0.103, and 0.033 1/min, respectively. Biodegradability and mineralization tests also confirmed the efficacy of the photocatalytic system with synthesized nanocomposite. Therefore, the FSEZAL photocatalysts exhibit promising potential for use in water treatment, particularly in the mitigation of toxicity associated with antibiotic waste.