Effect of Scaling on Electrosorption Desalination and Its Control
ZHAO Xue-na NI Wen CHEN Zhao-lin
State key laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education University of Science and Technology Beijing State key laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education University of Science and Technology Beijing State key laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education University of Science and Technology Beijing
Abstract：The effect of scaling on electrosorption desalination was studied by using electrosorption technology to desalt feed water containing different concentrations of Ca2+ and high concentration bicarbonate (HCO3-). The experiments were carried out at three Ca2+ concentrations of 40, 144 and 350 mg/L, respectively. The results show that the desalination efficiency drops remarkably at higher Ca2+ concentrations. Analysis of changes of ion removal rate, ion desorption rate and initial working current reveals that the calcium carbonate scale formed in the electrosorption module is a result of the interaction between Ca2+ and HCO3-, which causes the decrease of electrical double layer capacitance of electrode material, and therefore affects the desalination effect. Calcium carbonate can be dissolved after using acidification-stripping as pretreatment to obtain HCO3- concentration of 100 mg/L, which results in the improvement of desalination of the module. The crystallization and dissolution mechanism of calcium carbonate in the module are also discussed based on HCO3- ion residue and pH change in the working effluent.
2008, Vol. 8 
