Electrochemical treatment of wastewater: Selectivity of the heavy metals removal process

Abstract

Electrochemical processes have been known as a very efficient method for the industrial wastewaters treatment, especially for the removal of heavy metal ions. In this work, we would like to provide a method that not only effectively treats heavy metal ions but also carries out the process with a notable selectivity rate. An electrochemical cell with conductive carbon fibers cloth cathode and Platinum coated titanium panel anode (5 × 5 cm), low voltage supply energy of 10 V, and pH value of 6.8 is designed to remove Coppers, and Nickels out of the solutions contains Nickel Sulfate and Copper Sulfate (0.06 M).There are modifications applied to the electrode to improve its conductivity and durability, the two factors that may effect directly on the efficiency of the whole process. The result we obtained shows a good and promising data with high removal efficiency (up to 97%) during the 20 h working time. Together with the removal process, the properties of electrode materials are also well investigated. With the conductive carbon cloth shows its superiority, the electrochemical cell in this work become a very versatile system. In that manner, we provide a system which is not only can treat the wastewater, but also creating energies such as hydrogen and oxygen, collecting of heavy metals in hydroxide form, and can be easily improved to a continuous process with higher efficiency and larger application.Furthermore, the affection of electrode arrangement is carefully studied and revealed its properties, providing a chance applying the method to actual industrial purpose. With a close, medium and far distance of the two electrodes we arrange, the result of removal heavy metal ions is differently achieved (97, 96.5 and 71%). Technical problems appear during the process seems to be minor and could be solved quickly by a simple solution which will be described in the later part. However, a single effective process to treat the wastewater we introduced here is just the beginning. A continuous system which can be operated for a longer time, more effective and creating a decent amount of energies would be welcome to investigate.