Paper Title
Photocatalytic Treatment of Olive Mill Wastewater by Nano-Go/M Composite, Recovery and Reuse of Nanoparticles and Treated Wastewater

Abstract
Olive mill wastewater (OMW) is an important environmental problem, particularly in the Mediterranean countries such as Turkey. In order to solve this problem, the effective performance of photocatalysis technique in the treatment of OMW has been investigated using graphene oxide magnetite (Nano-GO/M) composite. In the present work, the effects of increasing Nano-GO/M concentrations (1 g/L, 2 g/L, 3 g/L and 5 g/L), irradiation times (15, 30, 45 and 60 min) and pH (4, 7 and 10) were studied. The maximum photocatalytic pollutant removal efficiencies for COD, total phenol and TS obtained under 300 W UV light. They were 86%, 94% and 96% at the optimum Nano-GO/M concentration (2 g/L). Nano-GO/M could be reused after six sequential cycle with no significant lost. Moreover, two different polyphenol, namely gallic and p-coumaric acid, concentrations were measured. The treated wastewater can be used as irrigation purpose by measuring some additive parameters. Index Terms— Graphene, Olive Mill Wastewater, Photocatalysis, Recovery