Synthesis of Zinc aluminate nanoparticles from aluminum / zinc sludge for degradation of brilliant cresyl blue under visible light irradiation

Abstract

Scientists and researchers from all over the world are paying close attention to the recycling of industrial waste into new materials. Aluminum and zinc sludge powders were gathered from aluminum sheets and big iron manufacturers to be used as starting materials in the synthesis of zinc aluminate nanoparticles. The XRF, XRD, and DTA examinations were used to characterize the collected sludge powders. The main components of aluminum and zinc sludges, according to the findings, are gibbsite (Al(OH)3) and hydrozincite (Zn5(CO3)2(OH)6), respectively. Without any primary advanced chemical treatments, the collected sludges were used to perform solid-state reaction (SSR) and molten salt synthesis (MSS) at 1100°C. XRD, FTIR, XPS, SEM, and TEM examinations were used to characterize the synthesized samples. Both SSR and MSS deduced pure phase zinc aluminate nanoparticles, with crystallite sizes of 17.4 and 12.7 nm for SSR and MSS samples, respectively. The microstructure of the MSS sample was characterized by a high structure homogeneity, whereas, the high degree of particle aggregation was shown by the SSR sample’s microstructure. The optical properties of the synthesized SSR and MSS samples were studied by using UV-visible and PL spectroscopy. The bandgap energies for SSR and MSS samples were calculated to be 2.78 and 2.48 eV, respectively. These samples are utilized in the photocatalytic degradation of the brilliant cresyl blue dye (BCBD), owing to their tiny bandgap energies and high absorption efficiency. The photocatalytic degradation percent of BCBD reached 94.5% and 86.7% by using MSS and SSR samples, respectively, at the optimum conditions of pH (10), dye concentration (40 mg/l), and sample dose (1 g/l).

Keywords

• solid state reaction
• molten salt synthesis
• industrial waste
• zinc aluminate nanoparticles