The experiment is setup in a H-Type electrolytic cell. Catholyte consists of 300mL of water; 5g of sodium hydroxide; 1g of sodium sulfate and 100mg of cerous sulfate as catalysts; and a lead sheet as cathode. Anolyte consists of 40mL of water, 1.1mL of sulfuric acid and a lead sheet as anode. The cell is heated to 75 degrees Celsius and 100mg of indigo synthetic is added. A DC 12 volts power supply is taken; the positive alligator clip is connected to the anode while the negative alligator clip is connected to the cathode. Hydrogen gas is released in the catholyte and indigo will get reduced to indoxyl.
As the electrolysis was allowed to run for 10 minutes, the catholyte barely changed color. But when the experiment was continued for an hour, the catholyte had slightly turned green. In order to save time, the catholyte was decanted and the sediments were found to be yellow in color. When the sediments were allowed to dry and get oxidized, the color of sediments changed from yellow to blue.
Results show that an electrolytic method for reducing VAT dyes is indeed a very time consuming process but definitely a safe alternate method that actually works. In the years to come, this process will be further researched on how it can be sped up.
The project was to test whether or not electrolysis can reduce VAT dyes without the assistance of sodium hydrosulfite, which is the commercial toxic reducing agent used by VAT dyers.
Science Fair Project done By Uppili S. Raghunathan