However, H+ ions move more quickly than do hydroxide ions [11]. Hydroxide ions
created at the cathode move towards the anode before they meet the acidic front
created by H+ ions from the anode [9]. In soil contaminated with metal ions (in this
experiment Cu2+) the HO- ions encounter Cu2+ ions, prior to being neutralized by H+.
This encounters precipitation of insoluble Cu(OH)2 close to the cathode, followed by
precipitation of copper oxide, inhibiting the reclamation of copper ions [12].