الفهرس 
Chapter 1 : IntroductionOnly 14 pages are availabe for public view
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Abstract
Chemical coagulation is commonly used in raw water and wastewater treatment plants for the destabilisation of pollutants to facilitate their removal in subsequent separation processes. Aluminium and iron salts are used in coagulation process as a source of metal cations. Recently Electrocoagulation (EC) has been used for the treatment of water and wastewater as an alternative to conventional coagulation process. In this process the metal cations produced from the electrolysis process in the presence of iron and aluminium electrodes are used in coagulation process. The produced cations formed different hydroxide metals, which are affected by the change of solutions pH, as the pH of solution is raised as a result of the formation of hydroxide metals. EC has many advantages over conventional chemical coagulation (CC), where it has low sludge production, less environmental pollution, easily applied. The main disadvantages of EC process are the high pH and total dissolved solids (TDS) of the treated effluent. The present work concerned with studying the possibility of enhancing EC process for the removal of Chlorpyrifos pesticide from wastewater by the addition of powder activated carbon (PAC) as a sorbent to improve the drawbacks of EC. The effect of the PAC dose, initial concentration of pesticide, initial feed TDS, solution pH, and the applied voltage atconstant temperature and distance between the used electrodes was investigated. It was found that the removal efficiency in the 0.25g/l of PAC using EC process at initial concentration of pesticide (1600mg/l) at pH 8 was61.5%, with an effluent pH 8. In addition PAC in EC treatment increased the removal efficiency in early stages of operational time under various feed solution TDS and had the same effect on solution pH with an effluent of pH 8. The optimum removal efficiency for EC and pH was achieved at a solution pH 7±0.5 with removal efficiency of 81.3%, while the addition of PAC as an adsorbent achieved a removal efficiency of 92.9% for high concentrations of Chlorpyrifos pesticide 1600mg/l. Activated carbon was able to enhance the EC performance, by decreasing the TDS of the treated effluent, keeping the pH constant during the experiment, and increasing the removal efficiency of Chlorpyrifos pesticide. The electrosorption removal efficiency and sorption capacity of activated carbon are directly related to initial concentration of TDS concentration, and applied voltage. The amount of activated carbon is directly related to TDS removal efficiency, and inversely to activated carbon sorption capacity.