ISSN: 2641-9459
Authors: Oztekin R*
In this study, the magnetic nickel (Ni) doped aluminium trioxide (aluminium oxide or alumina, Al2O3) based titanium dioxide (TiO2) [Ni-Al2O3/TiO2] nanocomposites (NCs) was used for the photocatalytic oxidation (photo-oxidation) of pollutant parameters {chemical oxygen demand (COD) components [CODtotal, CODdis, CODinert]}, toxic polyphenols [catechol, 3-hydroxybenzoic acid, tyrosol, 4-hydroxybenzoic acid, 4-hydroxyphenylacetic acid, 3-hydroxyphenylpropionic acid, 4-hydroxyphenylpropionic acid, 3,4-dihydroxyphenylethanol, 3,4-dihydroxyphenylacetic acid], and toxic polyaromatics [aniline, 4–nitroaniline, o–toluidine, o-anisidine, benzene, nitrobenzene, ethylbenzene, 3,6-bis(dimethylamino)durene, benzidine, dimethylaniline, 3,3–dichlorobenzidine]} from the olive mill effluent wastewaters (OMW), at different mass ratios of Al2O3, TiO2 and Ni (1%/5%/10%; 10%/1%/5% and 1%/10%/5%), at increasing photooxidation times (10, 30, 60, 100 and 120 min), at different Ni/Al2O3/TiO2 photocatalyst concentrations (50, 250, 500 and 1000 mg/l), pH values (4.0-7.0-9.0 and 10.0) and temperatures (15°C, 25°C, 50°C and 80°C), under 500 W ultraviolet visible (UV-vis) and 50 W sun lights irradiations, respectively. The acute toxicity assays were operated with Microtox (Aliivibrio fischeri also called Vibrio fischeri) and Daphnia magna acute toxicity tests. The significance of the correlations between data of all experimental samples were determined using the Analysis of Variance (ANOVA) test statistics. Under the optimized conditions, the maximum CODdis, total phenol and total aromatic amines (TAAs) photooxidation yields were 98%, 88%, 94%, respectively, at pH=9.0, at 500 mg/l Ni/Al2O3/ TiO2 NCs, under 500 W UV-vis light, after 100 min photooxidation time, at 50°C, respectively. The photooxidation yields in OMW under sun light was lower than the photooxidation yields in the OMW under UV-vis light. 94.44% maximum Microtox acute toxicity yield was found in Ni/Al2O3/TiO2 NCs=500 mg/l after 150 min photooxidation time, at 60°C. 90% maximum Daphnia magna acute toxicity removal was obtained in Ni/Al2O3/TiO2 NCs=500 mg/l after 150 min photooxidation time, at 60oC. Microtox acute toxicity test was more sensitive than Daphnia magna acute toxicity assay.
Keywords: Acute Toxicity Assays (Aliivibrio Fischeri, Daphnia Magna); Magnetic Nickel Coated Aluminium Trioxide Based Titanium Dioxide Nanocomposites; Olive Mill Effluent Wastewater; Photocatalytic Oxidation (Photo-oxidation); Polyaromatics and Polyphenols; Ultraviolet Visible and Sun Light Irradiations
