Green fabrication and physicochemical investigations of zinc-cobalt oxide nanocomposite for wastewater treatment

This study was planned to investigate physicochemical, adsorption/desorption, photocatalytic (reuse) properties of Wedelia bifiora (W. bifiora) mediated zinc-cobalt oxide nanocomposite (ZnCo2ONC). The surface morphology was inspected through scanning and transmission electron microsoopies (SEM and TEM) and the average particle size estimated from TEM image was 26.06 nm. The X-ray diffraction (XRD) analysis was conducted for crystallographic study and the derived crystallite size was 17.62 nm. The texture parameters were extracted from N-2 adsorption-desorption data using Barratt, Joyner and Halenda (BJH), Bruner, Emmett and Teller (BET) models and the Seu was found to be 51.23 m(2)g. The Diffuse reflectance spectroscopic analysis (DRS) was carried out to study the optical properties and the band gap derived from Tauc's plot is 2.26 eV. The chemical moieties in the samples were identified via energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The ZnCo2O4 NC was used for the adsorption of Cr(VI) ions from aqueous media and the nature of adsorption process was explored via Freundlich and Langmuir equations. The thermodynamic analysis reveals the endothermic mode of the adsorption process and 1:1 interchange mechanism was extracted for Fr and Cr (VI) ions. The photocatalytic efficacy of ZnCo2O4 NC was scrutinized during the mineralization of rhodamine 6G (Rh-6G) under simulated solar light and 98.92% was degraded in 330 min. Desorption and recycling studies was also done to explore stability and reuse capability of ZnCo2O4NC. (C) 2020 Elsevier B.V. All rights reserved.