Removal of natural organic matter from aqueous solutions by electrocoagulation

Abstract

Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addition, it can deteriorate the performance of water treatment process including coagulation, adsorption, and membranes. NOM also reacts with chlorine in the chlorination process and may form disinfection by-products. The present study was carried out in laboratory-scale in a batch system using a cylinder shape reactor with effective volume of 2 l. The initial NOM concentrations during the study period were 10, 25, and 50 mg/l. After specific time intervals, samples were taken from the reactor and filtered. Finally, the NOM removal according to total organic carbon (TOC) content of the samples that were analyzed with a TOC analyzer. The results showed that the highest NOM removal efficiency for three initial concentrations 10, 25, and 50 mg/l were 91, 94, and 82%, respectively. These removal efficiencies were obtained at pH 7, contact time of 20 min, and electrical current of 0.1 A. The electrical energy consumption was 0.08, 0.06, and 0.03 kWh/m3, respectively. In this study, the application of electrocoagulation (EC) treatment method using combined Al and Fe electrode was examined to remove NOM from aqueous solution. Based on the obtained results, the EC can be used as an effective method for removing NOM from aqueous solution.

Keywords

• electrocoagulation
• natural organic matter
• bipolar and monopolar
• aluminum
• iron