الفهرس 
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Abstract
This study presents some of advanced oxidation processes to eliminate pollutants in paper mill wastewater by homogenous photocatalytic oxidation such as, UV, UV/H2O2, Fenton and photo Fenton processes. As well as heterogeneous photocatalytic oxidation processes using TiO2. The results obtained in this work can be summarized as follow:
1- By application of UV only, it was found that the percent removal of COD is increased in the alkali medium. The best results was at pH 8 with COD removal of 22.4 % at 90 min irradiation time
2- Using UV/H2O2, the rate of COD removal increased compared to that of direct photolysis by addition of H2O2. The percentage removal of COD increased when hydrogen peroxide concentration increased, the optimum amount of hydrogen peroxide added was 5 ml/L with
% COD removals of 56.29 % at pH 3 within 60 min irradiation time
3- Using Fenton reaction, The optimum doses obtained of Fe(II) and H2O2 are 0.75 g/L and 2 ml/L respectively. At optimum pH 3 and optimum reaction time 150 min the COD removal was 54.04 %.
4- For Photo-Fenton reaction, the results indicated that the optimum conditions are 30 min irradiation time, pH 3, 1.5 ml/LH2O2 and 0.5g/L Fe SO4 under these conditions %COD removal found to be 79.75% .
5- For heterogeneous solar photocatalytic oxidation using commercial TiO2, the results indicated that the optimum conditions were 180 min time, pH 10 and 0.75 g/L TiO2, the %COD removal was 39.45% at optimum conditions. By addition 2 ml/L H2O2 under the same conditions %COD removal increased to 54.89 %.
6- For heterogeneous photocatalytic oxidation using prepared nanoparticales TiO2, the optimum conditions are 180 min irradiation time, pH 10 and 0.75 g/L for TiO2 dose, the % COD removal was 74.79 %. By addition of 2 ml/L H2O2 under the same conditions the COD removal increased to 77.9 %.
7- For heterogeneous photocatalytic oxidation under UV irradiation using commercial TiO2, the results indicated that the optimum conditions were 120 min irradiation time, pH 10 and 0.75 g/L TiO2, %COD removal was 42.3%, By addition 2 ml/L H2O2 under %COD removal increased to 73.5 % within120 min. Using prepared nanoparticales TiO2, the results indicated that the optimum conditions were 105 min irradiation time, pH 10 and 0.75 g/L TiO2, %COD removal was 59.3 % obtained, By addition of 2 ml/L H2O2 under the same conditions %COD removal increased to 95 % within120 min.
8- For heterogeneous photo catalytic oxidation using prepared Iron doped TiO2, phenol was taken as model compound. The results indicated that under visible light irradiation the optimum conditions were 180 min irradiation time, 150 ppm Fe- dopedTiO2 %phenol removal was 33.5%. By addition of 0.025 ml/L as H2O2 %phenol removal increased to 35.5 % within120 min.
9- In case of solar photo catalytic oxidation using prepared Iron doped TiO2, phenol was taken as model compound. The results indicated that under solar light irradiation the optimum conditions were 180 min irradiation time, 150 ppm Fe doped TiO2 % phenol removal was 81.82% attained. By addition of 0.025 ml/L H2O2 under the same conditions %phenol removal increased to 100 % within 60 min.
10- The enhanced photocatalytic activity of the synthesized nanoparticles TiO2 catalyst in paper mill wastewater is attributed to the increasing of crystalline size and surface area than the commercial TiO2.
11- The photoFenton was the best photocatalytic oxidation process used in this study for paper mill wastewater treatment either economically or for %COD removal.
12- The order of homogeneous photocatalytic oxidation process efficiency according to percent COD removal was as followed:
Photofenton > UV/H2O2 > Fenton > UV
On the other hand, the order of homogeneous photocatalytic oxidation process from the economical point of view is as follow
UV/H2O2 > Fenton > photoFenton.
Meanwhile, nano sized prepared TiO2 was more cost effective than commercial TiO2 and showed higher % COD removal.