Synthesis and characterization of nanomaterials and nanocomposites : environmental applications

Abstract

In this study, we report the first successful biosynthesis of magnetic Nickel ferrite NiFe2O4 and Zinc ferrite ZnFe2O4 nanoparticles via a sono-chemical and Sol-gel methods using rosemary leaves extract as a multifunctional capping, reducing, stabilizing, chelating and gelling agent. This approach was undertaken with the aim of developing a catalyst for the photodegradation of the nonsteroidal anti-inflammatory drug Diclofenac Sodium (DS), and organic dye Malachite green (MG), which not only represents an environmentally benign alternative to conventional chemical methods but also resulted in NiFe2O4 and ZnFe2O4 NPs with enhanced structural, optical, and magnetic properties. Characterization by XRD and FESEM-EDX analysis indicated the formation of NiFe2O4 and ZnFe2O4 NPs with quasi spherical morphology. TEM/HR-TEM analysis revealing its spinel phase structure, with particle sizes ranging from 4-23 nm. FT-IR was utilized to elucidate molecular vibrations, while VSM revealed the superparamagnetic behavior of these NPs, this property enables their efficient recovery after the photocatalytic process. The photocatalytic degradation (PCD) of DS by NiFe2O4 and ZnFe2O4 NPs with a band gap energy of 2.7-3.32, was examined under ultraviolet light (UV-A) irradiation. Various operating parameters, including solution pH, pollutants concentration, and catalyst dose, were studied. The degradation kinetics were monitored using a UV-Visible spectrophotometer. The biosynthesized NiFe2O4 NPs via sonochemical method demonstrated a high degradation efficiency of 95% for Diclofenac Sodium in acidic pH conditions within only 140 min. While ZnFe2O4 NPs biosynthesized via sonochemical method and NiFe2O4 and ZnFe2O4 NPs biosynthesized by sol-gel method, with a band gap energy of 1.62, 1.93, and 2.35 eV, respectively demonstrated a complete degradation of Malachite green dye reach 100% for a short period of time under natural sunlight irradiation. The NiFe2O4 and ZnFe2O4 NPs exhibited excellent recyclability and maintained structural and photocatalytic stability over three consecutive photodegradation cycles.