Bulk or supported tungstophosphates? Antioxidant and antimicrobial activities following pesticide removal

Abstract

The study evaluates caesium, potassium, silver, and zinc tungstophosphates synthesized in bulk and Y zeolite-supported forms through a two-step process. Spectral investigation reveals the impact of cation size on tungstophosphates formation. The large cations form ion-ion interaction with the Keggin ion, while smaller cations form hydrogen bonds between the cation hydration sphere and terminal oxygens in the Keggin ion. Supported salts formation proceeds without Keggin ion distortion. Zeta potential showed the absence of particle aggregation for caesium and potassium tungstophosphate. Nicosulfuron removal by the supported salt exhibits enhanced retention, with the exception observed for zinc tungstophosphate suggesting a decomposition mechanism. Antimicrobial evaluations reveal silver salt's potency, especially in zeolite-supported form, emphasizing the role of zeolite support. In the presence of pesticide molecules, the antimicrobial activity of salts lowers, with the exception seen for fungus strain. The antioxidant assessments demonstrate superior inhibition for insoluble bulk salts, with caesium tungstophosphate exhibiting the highest inhibition, while supported silver salt enhances bulk salt performance. The presence of pesticides affects both antimicrobial and antioxidant activities, while a complex relationship with radical scavenging ability in bulk and supported salts is independent of their pesticide adsorption capacities. The study broadens the range of the versatile applications of tungstophosphates, highlighting their specific interactions with pesticides and their impact on bioactivity and environmental remediation.