Simultaneous removal of lead(II) and nitrate from water were investigated by using aluminum and iron electrodes at low voltage. The results showed that the pollutant removal not only increases with increasing voltage and decreasing electrode distance but also is inhibited by solution acidity. The overall removal is considered to include three synchronous processes, i.e. chemical reduction (CR), electrochemical reduction (ECR) and electrocoagulation (EC). At pH of 4–10 with electrode distant of 2 cm under 6 V, the ECR played great role on nitrate removal whereas both CR and EC hardly worked. However, it can be found that, in solution at pH 4–6, CR and ECR are main processes in lead(II) removal with no EC happening; at pH of 6–10, CR and ECR contributed more than EC. Therefore, we conclude that efficient lead(II) removal is mainly achieved CR and ECR rather than EC at pH of 4–10, whereas nitrate removal is by ECR. The optimal removals of lead(II) (99.7%) and nitrate (57.6%) were achieved at pH 6 with low applied voltage of 6 V and electrode distance of 2 cm. Finally, it was confirmed by the experiment using KNO3 instead of Pb(NO3)2 that the presence of lead(II) ions can significantly inhibit nitrate removal.
ASJC Scopus subject areas
- Safety, Risk, Reliability and Quality
- Waste Management and Disposal
- Process Chemistry and Technology