How to Make a Reverse Electrolysis Machine

Standard electrolysis is a simple procedure, despite its scientific sounding name. Electrolysis literally means to split apart with electricity and refers to the principle of passing current through an electrolyte, causing the neutral molecules in the electrolyte to split and form negative and positively charged ions. Common usage for standard electrolysis is in electroplating, where you substitute the carbon anode for a piece of metal you want to plate. Reverse electrolysis involves placing a rusty or coated object in the middle of the electrolyte solution, while passing current between an anode and a cathode. This removes the coating from the object, rather than plating it like in standard electrolysis.

Things You'll Need

• Rusty piece of metal
• 2 copper rods
• 2 wires with crocodile clips
• Large plastic tub
• Water
• Bicarbonate of soda
• Power supply
• Gloves

Instructions

1. Connect the wires with the crocodile clips to the power supply, one to the negative terminal and one to the positive one. Hook the positive crocodile clip to one of the pieces of carbon to form the positive anode.

2. Hook the negative crocodile clip up to the other carbon rod to form the negative cathode. This is the only difference between ordinary electrolysis and reverse electrolyisis; in ordinary electrolysis, the goal would to plate a piece of metal with negative ions and you would therefore trade the positive carbon anode with whatever dull piece of metal you wanted to.

3. Fill the large tub ¾ of the way up with water and then add three cups of sodium bicarbonate. This creates an electrolyte. Pure water isn't used as an electrolyte because it contains too few positive and negative ions.

4. Carefully place the anode and cathode into the tub, ensuring the two pieces of carbon are not touching. Make sure the crocodile clips are not submerged in the electrolyte also, as this will cause them to rust. Place the rusty object you want to clean in the electrolyte, ensuring it is not touching either cathode or anode.

5. Set the power supply to a low power and turn on. Observe the reverse electrolysis process, as the negative oxygen ions are attracted to the positive anode. This causes a reaction between the metal anode and the oxygen ions, forming a coating of Iron Oxide on the positive anode. Continue until the anode is completely covered in rust.

6. Shut off the power. Remove the piece of metal from the solution with gloves and observe how the process has removed the rust.

References

• Rusty Iron: Metal Ageing, Patina and Rust
• Electrolytic Rust Removal