Microwave-assisted hydrothermal synthesis of CuWO4-palygorskite nanocomposite for enhanced visible photocatalytic response

Abstract

CuWO4-Pal nanocomposite formed by copper (II) tungstate nanoparticles with palygorskite clay mineral (Pal) was synthesized via coprecipitation method followed by microwave-assisted hydrothermal technique and applied in the photodegradation of the antibiotic ciprofloxacin (CIP) using visible-light irradiation. The formation of CuWO4-Pal nanocomposite was confirmed by XRD, Raman spectroscopy and DRIFT studies. X-ray photoelectron spectroscopy (XPS) and photoelectrochemical studies of the nanocomposite showed structural changes, which induced the formation of oxygen vacancies and better charge carrier mobility. Field emission scanning electron microscopy (FE–SEM) and transmission electron microscopy (TEM) images revealed the fibrous morphology of Pal as well as the control of CuWO4 crystal growth with the formation of the nanocomposite. The CIP photodegradation was influenced by the adsorption power and the pH solution. CuWO4-Pal exhibited 92% of CIP photodegradation and 50% of total organic carbon (TOC) removal using an initial concentration of 8 mg L−1 at pH 10 after 90 min. Together with the photoelectrochemical study, the scavengers used indicated that the hole (h+) is the main oxidative species in CIP photodegradation.