Peroxymonosulphate activation by ultra-small Ni@NiFe2O4/ZnO magnetic nanocomposites for solar photocatalytic degradation of β-lactam antibiotic - cefadroxil

Abstract

In this study, ultra-small nickel nanoparticles on NiFe2O4 (Ni@NiFe2O4) and Ni@NiFe2O4/ZnO magnetic nanocomposites were synthesized and utilized for the solar light-driven photocatalytic degradation of cefadroxil. The drug cefadroxil is widely used to treat bacterial infections and cefadroxil is a non-biodegradable pharmaceutical compound detected in the groundwater sources because of its low removal efficiency. The Raman active phonon at 540 cm−1 confirms the presence of Ni nanoparticles at the surface of NiFe2O4/ZnO. DR-UV-Vis analysis exhibited surface plasmon resonance at 350 nm for ultra-small nickel nanoparticles. The observed optical bandgap values for Ni@NiFe2O4 and NiFe2O4/ZnO are 1.2 eV and 2.43 eV, respectively. Which indicates that these magnetic nanocomposites can be utilized for the mineralization of cefadroxil (β-lactam antibiotic) under ambient environmental conditions. The efficiency was determined by the direct solar light driven photocatalytic oxidation of cefadroxil in the presence and absence of peroxymonosulphate (PMS). The experimental findings exhibits that ∼95 % of cefadroxil (CDL) was eliminated by the ultra-small Ni@NiFe2O4/ZnO within 60 min (k = 7.5 × 10−4 s−1) of direct solar light irradiation. Further, the addition of PMS enhanced the photodegradation to achieve 100 % cefadroxil oxidation within 40 min (k = 25 × 10−4 s−1) of direct sunlight. The efficiency of the nanocatalyst was compared with controlled experiments and was found to be Fe2O3 < ZnO < TiO2 (P25) < Ni@NiFe2O4 < Ni@NiFe2O4/ZnO under absence and presence of PMS. Moreover, ultra-small Ni@NiFe2O4/ZnO nanophotocatalyst were stable up to 3 consecutive cycles.