Splitting of a salt into an acid and a base corresponding to the following reaction:
4 NaCl + 6 H2O ---> 4 NaOH + 4 HCl + 2 H2 + O2
The reaction is performed in an electro-electrodialysis cell with a variety of setups. A typical setup is shown in the following picture:
The picture shows a four chamber cell, in which the salt chamber (salt NaX) with the adjacent anion and cation exchange membranes is the heart.
Within this setup, the cations moves toward the cathode entering the catholyte solution: the cation hydroxide is formed. The anions move toward the anode entering the acid solution, which is separated from the anolyte solution by a cation exchange membrane. Through this, protons from the anolyte solutions move into the acid chamber to produce the acid.
The four chamber cell process is a general process covering many applications. For example
The next image shows variations of this setup: In certain cases, the membrane between anolyte and acid is not necessary, in other cases, an separating membrane towards the catholyte is helpful.
Electromembraneprocesses for the Splitting of a Salt.