טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentDavid Sapir
SubjectElectrochemical Water Purification
DepartmentDepartment of Agricultural Engineering
Supervisors Professor Emeritus Zaslavsky Dan (Deceased)
Dr. Guetta Rami


Abstract

This thesis suggests a new physical approach for desalination. The method offered is the separation of salt from water by passing the solution through an electric field. The charge on electrodes causes the ions to move through the water to the electrodes, anions to anode and cations  to cathode. The electrode behaves like a capacitor, where one side of the capacitor - electrode is charged from the potential D.C source, and the other side is charged by ions from the solution (according to Diffuse Double Layer principles). Normally it is believed that high specific surface area of the electrode is required to increase the capacity of  the electrodes for ion adsorption   this way improves the separation of salt from water. Another benefit of the electrode is the option to recover the energy.

The novelty in this thesis is to utilize another phenomenon of attraction of solutes to the electrodes due to the high electrical field.

In measurement we have demonstrated the capability of such adsorption of solutes to reach hundred folds compared with the ionic neutralization. This is from a medium concentration solutions.  It reached even three thousand fold for sea water.

In addition, we have demonstrated the reduction of the energy consumption to about one half and recover nearly half of the energy invested.

These two innovations lead to a possibility to reduce the cost of desalination without membranes to a small fraction of the memebranes process.