Synthesis, characterization and photocatalytic degradation of chlorpyrifos by novel Fe: ZnO nanocomposite material

Abstract

In present work, the magnetically separable Fe–ZnO nanocomposites were successfully synthesized using metal nitrate precursors via hybrid precipitation and sonochemical method. The structural, morphological and optical properties of the nanocomposites were characterized by TEM, FE-SEM, XRD, FT-IR, UV–DRS, EDX and VSM. The XRD result shows that the Fe–ZnO consists of dual phases, i.e., ZnO and Fe, and the mean crystal size of the composite material was 66.7 nm. The microstructure analysis (TEM and FE-SEM) was carried out to study the size, internal and external surface morphology of the nanocomposite material. The average particle size was 30 and 85 nm for pure ZnO and Fe–ZnO, respectively. The EDX analysis confirms the presence of ZnO and Fe in the nanocomposite materials without any impurity. The optical band gap of the synthesized material was confirmed using UV–DRS, and it was found 3.23 eV for pure ZnO, whereas for Fe–ZnO it was 2.2 eV making it efficient for the visible light photocatalysis as well. FT-IR data indicate the characteristic vibrations at 454 cm−1 for Zn–O and 554 cm−1 for Fe–O–Zn. The magnetic property of the synthesized material was analyzed using VSM and results confirmed that the material exhibits room temperature ferromagnetism. The photodegradation activity of Fe–ZnO nanocomposite was evaluated on an organophosphate pesticide (chlorpyrifos) at different concentration under UV irradiation and analyzed by FT-IR, Raman and UV–Vis spectroscopy. The mineralization of pesticide was confirmed by reduction in TOC and COD values. Up to 93.5% degradation (10 ppm) was observed in 60 min using Fe–ZnO. The as-synthesized Fe–ZnO was found very effective for the degradation and mineralization of chlorpyrifos.