Abstract

Background: Chromium (Cr) is essential element used to plate other metals. Electroplating industry's effluents are the most important sources of chromium pollution in the environment. This paper describes a study conducted to determine the efficiency of reverse-osmosis (RO) as a membrane filtration technique for removal of Cr from synthetic wastewater samples prepared similar to electroplating effluents. Methods: The RO unit used in this study was a spiral wound module of 2521 TE made by a Korean CSM company. Synthetic wastewater samples containing Cr ions at various concentrations of 1 to 20 mg/L prepared and subjected to treatment by RO, and quantitative analysis accomplished by a colorimetric method. Evaluation of optimized conditions of treatment had also been carried out by determining the effects of changing operating pressure, temperature, and pH. of samples. Results: Optimum conditions of Cr-treatment by RO in 10 mg/L feed Cr concentration were determined to be in pH range of 6 to 7 and in temperature of about 25 degrees C at an applied pressure of 200 psi. Conclusion: Considering the efficiency of Cr removal, which was as high as 99% at the optimized conditions it could be, concluded that RO membrane process may selected and developed as an effective alternative for treatment of metal-contaminated effluents of electroplating and similar industries.