The influence of humic acids on desalination process with the use of electrodialysis

Abstract

With every year amount of drinking water in the world becomes smaller. One of the possible way to solve the problem with water scarcity is desalination. The aim of this paper is to evaluate the use of electrodialysis for salt removal in the presence of organic matter. During the tests installation PCCell BED-1-System was applied. Desalination was conducted with the use of standard ion-exchange membranes. The treated solutions contained 0.5 and 1 g NaCl/dm3. The solution poured into a diluate chamber was also supplemented with humic acids (concentration amounted to 5, 10 and 15 mg/dm3). The current intensity was equal to 0.11 A (current density equal to 1.72 mA/cm2). The process was terminated when voltage reached 24 V. During the tests conductivity, colour and voltage was monitored. Also specific electrical energy demand (EC) was calculated. It has been found that electrodialysis can be used as an effective method for salt removal. In most cases conductivity was reduced by approximately 90%. The main factor which influenced EC and process duration was mineral salt content. Besides, it has been observed that organic matter had a slight impact on the process course.