Degradation of Rh B and glycerol using contact glow discharge electrolysis (CGDE)

Abstract

In modern society, there is an increasing tendency of requirement for pursuing higher aes-thetic abilities. For example, dyeing and chemicals are one of the main perspectives in the creation of industrial pollution. As such, many different chemical methods have been devel-oped to get rid of the pollution through degradation of organic molecules. However, these methods have been still encountering the limit in low efficient process and complex proce-dures. It is still challenging to discover an approach to the improvement of degradation rate of the polluted organic contents.

In order to increase the degradation of polluted elements, the contact glow discharge elec-trolysis method was used with Cu and Au-coated Ti foil electrodes. It is the plasma dis-charge in cathode and the oxidation in anode that work together for chemical degradation.

It is found that a very low CGDE voltage is required to convert the glycerol in the solution in that glycerol is rapidly oxidized and transferred to chemicals such as glyceric acid, glyceraldehyde that are not toxic. The conversion rate is measured up to 81.27% at a con-centration of 8mL glycerol.

CGDE enable to cleave the organic molecules either in the plasma zone or on the plas-ma/solution interface through hydrogen abstraction and electron transfer. Four parallel metal foil electrodes (i.e. Ta, Cu, Ti and Au coated Ti) are proposed and utilized as cathodes in the two-electrode system as above and Rh B molecules are selected organic pollutants. The re-sults show the degradation rates are dependent on the electrical conduction of metal cath-odes. During the discharge process, the Ti-based foil produces TiO2 particles, which then act as catalyst in the electrolyte and perform the photocatalytic process along with the plas-ma discharge process to degrade organic pollutants. It is of particular interest that gold na-noparticles, generated from Au coated Ti foil film during electrode discharging, are less than 5 nm in size and further enhance the TiO2 photocatalytic activity. In fact, this bifunc-tional plasma discharge process to the degradation of water pollutant is the key finding in this thesis which can also provide an insight into more applications such as chemical con-version, water purification and dust pollution.