Synthesis of calcium aluminate nanoflakes for degradation of organic pollutants

Abstract

Calcium aluminate nanoflakes possessing a single crystalline orthorhombic Ca5Al6O14 phase and a thickness of about 50 nm were synthesized via a simple route. The elements O, Al, and Ca were confirmed in the nanoflakes by element mapping and X-ray photoelectron spectroscopy. Formation and growth of the nanoflakes can be explained by a nucleation and crystalline growth process. The nanoflakes exhibit a band gap of 3.87 eV which entails good photocatalytic activity towards gentian violet which, in aqueous solution at a concentration of 10 mg L−1, can be entirely degraded within 100 min upon irradiation of a 175 W mercury lamp using 1 g L−1 calcium aluminate nanoflakes as catalyst. The reaction rate constant is 0.032 min−1 which is six times higher than that using calcium aluminate nanostructures obtained from different conditions. The nanoflakes are recoverable and possess good stability for the gentian violet degradation.