Electric Field Assisted Photocatalytic Oxidation Treatment Of Water, Acid Orange Ii And 2,4-d

Many organic contaminants have adverse effects on the aquatic environment and procedures have to be found for their destruction. Conventional treatment processes are usually based on physic-chemical, biological and chemical processes. Some of these contaminants can be removed from the water by adsorption onto solids. The transfer of the contaminants from the water to another phase is not an ideal remedy, so further treatment may be required for the phase loaded with toxic organics. Photocatalytic oxidation using semiconductors is an alternative technology which may be used to purify water by destroying organic contaminants and producing C02, HiO and mineral acids such as HC1.In this work, a photoelectrochemical process in the degradation of Acid Orange II on a Pt/TiOz film electrode is investigated. By using the 300w high pressure mercury lamp and the voltage stabilized source of direct current, decolorization ratios higher than 78% are observed during a period of 5h. Comparing this value with the sum of the decolorization ratios obtained by a sole application of electrochemical (lower than 3%) and photochemical (about 23%) procedures, a significant synergic effect between both processes is observed. The degradation of Acid Orange II is of the apparent first order. The increase of Acid Orange II initial concentrations has remarkable effect upon the dye removal. The load of degradation increases from 0.22 to 0.55 (mg/(w-(w/m2)-h)) with the concentrations increasing from 10 mg/1 to 100 mg/1. The effects of adscititious voltage and pH value on the reaction of dyes removal are obvious while that of the amount of aeration is minor.On the other hand, the obvious photogenerated current is observed during thephotoelectrochemical degradation of 2,4-D by using the potentiostat. Both the degradated rate of 2,4-D and the current density increase with the increasing of applied bias potential, but the current efficiency decreases at the same time. The concentration of electrolyte has the same effect to the applied bias potential. The degradated rate of 2,4-D and the current density increase while the current efficiency decreases with the increasing of the concentration of electrolyte. The degradation of 2,4-D and the current density increase with the decreasing of pH value. But the current efficiency reach the maximum at pH=6.84. The current efficiency decreases when the pH value is lower or higher 6.84.