A study of methods for eliminating Cr (VI) from industrial waste & employing the electrochemical method in the optimum

Cr (VI) is a major pollutant, which enters the environmental cycle & endangers both the environment & man. Many methods have been employed to eliminate it from industrial wastes. Such methods include reverse osmosis, electro dialysis & ion transfer, which very costly. We have considered an electrochemical method which does not require any chemical compounds. After choosing the method for eliminating Cr (VI) the following parameters where optimized for a 600 ml solution of electrolyte. Optimum current: 300 mA for 75 min in constant current method. Optimum potential: 3.5 V for 60 min in constant potential method. Agitation effects reduce time by 15 min. optimum temperature: 25 C. optimum pH: 5 .cathode: 316 steel, with dimensions of 5×10 cm. anode: platinum bar of 2×40 mm size. Distance between electrodes: it had no effect in the constant potential method, but reducing the distance was better in the constant current method. Cathode width: no effect in constant current method, but reducing the width was better in the constant potential method. We found the constant method to be superior because it is not effect by medium parameters such as pH & electrode separation. it is possible to reduce Cr(VI) concentrations from 100 ppm to less then 1 ppm, resulting in an efficiency of 100% ,using an electrolysis bath of 1 m3, current of 500 A for a time of 1 hr.

کلیدواژه ها:

Cr (VI) ، Industrial Waste ، Eliminating ، Electrochemical