Author/Authors :
Farrokhi، Mehrdad نويسنده Department of Environmental Health Engineering, Faculty of Health, Guilan University of Medical Sciences, Guilan, Iran Farrokhi, Mehrdad , Yang، Jae-Kyu نويسنده Division of General Education, Kwangwoon University, Seoul, Korea , , Lee، Seung-Mok نويسنده Department of Environmental Engineering, Kwandong University, Gangnung, Korea , , Shirzad-Siboni، Mehdi نويسنده 1Department of Environmental Health Engineering, School of Health, Guilan University of Medical Sciences, Rasht, Iran ,
Abstract :
Effect of different type of organic compounds (humic acid, oxalate, ethylenediaminetetraacetic acid, nitrilotriacetic
acid, phenol) on the photocatalytic removal of cyanide with TiO2 or ZnO was studied in this work with variation of
the solution pH, contact time, initial cyanide concentration and type of organic compounds. Photocatalytic
oxidation efficiency of cyanide with TiO2 was greatly affected by the solution pH. It increased as the solution pH
decreased. Also maximum removal of cyanide by ZnO was observed near at neutral pH because of the reduced
photocatalytic activity of ZnO at exceedingly low and high pH values originated from either acidic/photochemical
corrosion of the catalyst and/or surface passivation with Zn(OH)2. Removal efficiency of cyanide greatly decreased
in the presence of humic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid compared to that without
presence of organic compound because of the competitive oxidation as well as surface blocking by relatively large
organic compounds. The oxidation pattern of cyanide was better described by first-order kinetic model. Finally
photocatalytic reaction with TiO2 or ZnO can be effectively applied to treat synthetic wastewater contaminated
with cyanide.
