Plasmacatalytic removal of lead acetate assisted by precipitation

- Lead acetate molecule is more toxic than lead ions.
- Lead acetate is soluble in water but it weakly ionises in this aqueous medium.
- We degraded separately lead acetate molecules in water by GAD and GAD/TiO2.
- The released Pb2+ ions were removed by precipitation process.

The Gliding Arc Discharge (GAD) is an efficient non-thermal plasma technique able to degrade organic compounds dispersed in water at atmospheric pressure. The degradation of the organometallic lead acetate (PbAc) in aqueous solution was performed by two distinct plasmageneous processes: GAD and GAD/TiO2.The global oxidation of the organic matter was followed by Chemical Oxygen Demand (COD) and the mineralization was determined by the Total Organic Carbon (TOC). The Pb2+ ions released during the degradation process were measured by Atomic Absorption Spectroscopy (AAS).For 2 h of GAD treatment, the degradation rate of PbAc (10 mM) reached 83% and for the same duration of GAD/TiO2 process ([TiO2] = 1 g L−1), it reached 93%.The release of Pb2+ ions in the solution was respectively of 95% and 57% for GAD and GAD/TiO2 processes. The released Pb2+ ions were removed by precipitation process in a basic medium at pH = 11.1.A reaction mechanism was proposed to explain the PbAc molecule degradation and the Pb2+ elimination.

'GAD-precipitation' and 'GAD-TiO2-precipitation-adsorption' mechanisms.