Development of multifunctional Fe3O4@SiO₂@Ag@Ag2O nanocomposite for paraben detection and Pseudo-Fenton catalytic degradation

Multifunctional Fe 3 O 4 @SiO 2 @Ag@Ag 2 ONCs was synthesized for its dual ability as a colorimetric sensor for detection and Fenton-like catalytic degradation of parabens. The biosynthesis of Ag@Ag 2 ONCs performed using algae extracts. The nanocomposite uses the synergistic advantage of the magnetic properties of Fe₃O₄ and the catalytic activity of Ag@Ag₂O, thereby increasing the efficiency of hydroxyl radicals. The Fenton-like mechanism employed in this work operates efficiently at an alkaline pH (pH 8), enhancing the oxidation of parabens using H 2 O 2 . Kinetic measurements were completed within 10 min, which showed the excellent catalytic properties of composite. The method provided 3.0–40.0, 4.0–100.0, 4.0–100.0 and 8.0–100.0 μM linear dynamic ranges with detection limits of 0.85, 1.02, 2.5, and 2.47 μM for methylparaben (MP), butylparaben (BP), propylparaben (PP) and benzyl paraben (BenzylP), respectively. The kinetic profiles well fit the pseudo-first-order model. The apparent rate constant value of 3.0 × 10 −4 s −1 for BenzylP, PP, and BP and 4.0 × 10 −4 s −1 for MP was obtained. Therefore, the method was also used for the quantification of parabens in (spiked) seawater and algae samples, and well recovery values were obtained. The results showed that the Fe₃O₄@SiO₂@Ag@Ag₂ONCs can efficiently degrade parabens in real samples, such as seawater and algae. Also, indirect confirmation experiments are used to investigate the production of OH . Spectrophotometric degradation of MP using NaBH 4 and methylene blue (MB) using H 2 O 2 were performed in the presence and absence of the composite. Both degradations occurred very rapidly in the presence of the composite also the MB spectral shape changed. These results, together with the kinetic data, confirm the generation of OH in the proposed Fenton-like mechanism. • Biosynthesis of Ag@Ag 2 O nanostructure using algae extracts was performed. • Economical and sensitive colorimetric detection of parabens without large pre-treatment steps. • Fenton Catalytic Degradation of parabens were catalyzed by Fe 3 O 4 @SiO 2 @Ag@Ag 2 O nanocomposite. • Wide linear ranges and low detection limits were obtained within 10 min. • Recovery values show applicability of method for parabens detection in sea water and alga samples.