الفهرس 
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Abstract
The present work deals with the removal of sulfide ions from industrial wastewater by electrocoagulation using an electrolytic cell with new design. The cell consisted of an array of closely spaced woven iron screens anode enclosed between two iron screen cathodes. Separation efficiency and rate of separation were studied under different conditions of the following variables:1. Current density (mA/cm2).2. Initial concentration of sulfide (ppm).3. Electrolyte (NaCl) concentration (g/L).4. Bed Thickness (no of screen ber bed).5. Electrode orientation (horizontal vs. vertical). 6. Mesh number. 7. pH. The present study leads to the following conclusions: (1) The use of horizontal and vertical screen stack as an anode in an E.C. cell is a promising electrode geometry in view of the high area per unit volume of the electrode and its high turbulence-promoting ability when subjected to the up-rising gas-liquid dispersion. Besides the high cell productivity, the cell is efficiently stirred by bubbles evolved at the cathode. This obviates the need for external stirring and lowers the capital and operating costs of the process.
(2) The use of vertically oriented screen electrodes is more economical than horizontally oriented screen electrodes at relatively low current densities ( 8 mA/cm2). The use of horizontally oriented screen electrodes is more economical than vertically oriented electrodes at high current densities ( 8 mA/cm2). (3) The % removal increases with increasing c.d, pH, electrode thickness (No of screens per electrode), and NaCl concentration. However, it decreases with increasing the initial concentration. (4) Energy consumption ranged from 0.803 to 39.28 kW.h/kg for cells with horizontally oriented electrode. While for cells with vertically oriented electrodes, energy consumption ranged from 0.27 to 48.2 kW.h/kg depending mainly on the operating current density. (5) The present work has shown that the performance of a cell with horizontally oriented electrodes is superior to the traditional vertical electrode cell in conducting electrocoagulation of sulfide solution, where % of sulfide removal researched to100% after 18min at c.d 8 mA/cm2, mesh no=10, bed thickness =5screen per bed, pH=7, NaCl conc=30g/L, and initial sulfide concentration 250ppm.