Retrievable nano-sized Co–Mg–Zn ferrite as an active photocatalyst and adsorbent for removing organic and biological contaminants for water purification

Abstract

The water contamination such as organic dyes and microbes raise global environmental concerns. The UV light-driven spinel ferrites are promising photocatalysts for water purification. In this present work, Co-doped Mg–Zn nanoferrites of composition Mg0.4Zn(0.6-x)CoxFe2O4 (x = 0–0.6 with step size 0.1) were successfully prepared by a wet chemical citrate precursor method. The potential of synthesized nanoferrites were tested for the removal of rhodamine B dye and Candida albicans fungi inhibition. The structural, morphological and optical studies were undertaken; wherein XRD examination confirmed the cubic spinel structure of the synthesized nanoferrites, with an average crystallite size between 27 and 38 nm. Scanning electron microscopy (SEM) disclosed that these ferrite nanoparticles have spherical shapes with nanometric particle size. The spinel structure of the produced nanoferrites was again shown by the bands at 523 and 407 cm−1 in the FTIR spectra. The band gap of 1.78–1.99 eV was confirmed by the Kubelka-Munk plots. The enhanced photocatalytic performance (95 %) for the Rhodamine B dye degradation was obtained due to the narrowing band gap (1.78eV) of Mg0.4Zn0.1Co0.5Fe2O4 ferrite nanoparticles. Also, this highest photocatalytic efficiency was attained at the maximum rate constant (k = 0.078 min−1). The mechanism involved in the photocatalysis process has been discussed. All the prepared nanoferrites exhibit an excellent antimicrobial effect on Candida albicans fungi with concentration x = 0.5 showing a better antimicrobial effect (76 %). Hence, these Co–Mg–Zn nanoferrites can act as active photocatalysts and adsorbents for removing organic and biological contaminants for water purification.