The Chemical Compositions of Desalinated Water from Sea Water by Electrodialysis

Abstract

The behavior and chemical compositions (major and some minor constituents) of desalinated water from sea water by electrodialysis were studied. And, the resultant waters were compaired with the mean compositions of the waters of Japanese rivers and other rivers in the world. As the result, the following three forms as to the chemical species were obsereved:
(1) These chemical species which were almost entirely and electrically rejected by the both membranes, remaining in the desalting chambers. They were mainly non-charged chemical species such as boron and silicon.
(2) Those species which were mainly transported by membrane from sea water. They were strong electrolytes such as mono-valent potassium and bromide ions.
(3) The intermediate of the above categories. They were some types of chemical species.
The desalinated sea water seems to have a sanitary problem for drinking as it contains remarkable quantity of boron. If the raw sea water is polluted with some heavy metals such as vanadium, lead and organic pollutants, they would remain in the desalinated water.