Remediation of Olive Industry Wastes via Sonication and Nano-metal Oxides

Abstract

The impacts of nano-sized metal oxides, specifically titanium dioxide (TiO2), nickel oxide (NiO), and zinc oxide (ZnO), on the ultrasound (US) of olive mill effluent wastewater (OMW) in Izmir, Turkey, were studied. Effects of increasing  US times, US temperatures on COD_dis, total phenol, color, TAAs removals were investigated. Among the different organic pollutants in OMW, phenols are considered the major pollutants since they are harmful to plants, animals and human. The US mechanisms for the removals of pollutants from the OMW were investigated. The polyphenols, the total aromatic amines and their metabolites were identified. The effects of nano TiO₂, nano NiO and ZnO on the COD_dis, color, total phenol, TAAs removals in the OMW were investigated. 150 min US alone provided 61%, 50%, 61% and 66% dissolved chemical oxygen demand (COD_dis), color, total phenol and total aromatic amines (TAAs) removals, respectively, at 25^oC. 90% maximum TAAs, 97%total phenol, 94%color, 97%COD_dis removals were achieved  with 5 mg/l nano-sized ZnO, 4 mg/l nano-sized TiO₂, 4 mg/l nano-sized TiO₂, 4 mg/l nano-sized TiO₂, respectively, throughuot US.