Electrochemical study and extraction of Pb metal from Pb oxides and Pb sulfate using hydrophobic Bronsted acidic amide-type ionic liquid: A feasibility demonstration

摘要

Electrodeposition of lead (Pb) is important because of the application for energy storage and Pb recovery. Water, however, is not a good solvent because many Pb compounds, such as Pb oxides used in Pb storage batteries, are insoluble. Ionic liquids (ILs), especially for deep eutectic solvents (DESs), have been used for Pb electrodeposition. However, most DESs are water-miscible. Here, a hydrophobic Bronsted acidic amide-type IL, protonated betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]), was used to dissolve PbO and PbO2 under an ambient air for the voltammetric study and electrodeposition. PbSO4 was only slightly soluble but extraction of Pb metal was achieved from the PbSO4/[Hbet] [TFSA] paste. Very smooth, uniform, and crystalline electrodeposits were obtained from the PbO and PbO2 baths, respectively, regardless of potentiostatic or galvanostatic electrodeposition but dendritic Pb was obtained from DESs. The Pb species in the IL was carefully studied, and the different species might explain why different morphologies of Pb were obtained from this IL and DESs, respectively. This study demonstrates that a protic IL is appropriate to be used as the electrolyte for electrochemically extracting Pb from various water-insoluble Pb compounds.