Enhanced adsorption performance of polypyrrole composite electrode with ionic liquid doped for low concentration heavy metals in CDI

Recently, capacitance deionization (CDI) has attracted much attention as an energy-saving and high-efficiency wastewater treatment technology , in which electrode materials play a significant role. In this work, ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate)-doped composite electrode materials (PPy- IL /CS/CNT) were prepared by electrochemical deposition and applied in the heavy metal ions wastewater adsorption. Compared with PPy/CS/CNT, PPy -IL /CS/CNT has improved the specific capacitance (358.76 F/g) and specific surface (79.99 m 2 /g) because of the doping of IL, which substantially improves the agglomeration phenomenon in the morphology. After 1000 cycles of CV, the specific capacitance decay is only 13.51%, which shows that the prepared material has excellent cycling stability. The adsorption of PPy -IL /CS/CNT can reach 35.84 mg/g for 100 mg/L Cu 2+ solution, which is nearly 2 times as much as PPy/CS/CNT, in addition, the adsorption of Ag + (26.43 mg/g) and Fe 3+ (37.82 mg/g) by PPy -IL /CS/CNT is also pretty impressive. Therefore, this study presents an effective basis and new sight into the industrialization of CDI technology for the treatment of heavy metal ion wastewater.