Electrodeposition and recovery of copper from simulated wastewater using alkali-modified amidoxime carbon felt coated with polyacrylonitrile

Abstract

The recovery of copper ions by electrodeposition is a common method for the treatment of copper-containing wastewater, but the effect of using ordinary carbon felt electrode electrodeposition is not ideal. In order to further improve the electrodeposition effect of carbon felt electrode on Cu²⁺, in this study，polyacrylonitrile was coated on the surface of the carbon felt, after which the sample was subjected to amidoxime and alkaline hydrolysis. The modified amidoxime carbon felt was prepared by loading amidoxime, amide and carboxyl groups at the same time. The experimental results showed that the modified amidoxime carbon felt had good selectivity for Cu²⁺ during adsorption. Under the same experimental conditions, the adsorption and electrodeposition of Cu²⁺ by the modified amidoxime carbon mat were greater than those by the amidoxime carbon mat. Using modified amidoxime carbon felt as the working electrode and bare carbon felt as the opposite electrode, an asymmetric AC voltage with a frequency of 400 Hz, + 5 V (20 %) and −10 V (80 %) was applied at 25 °C, the initial concentration of Cu²⁺ was 100 mg/L, and the initial pH was 3.5. The Cu²⁺ electrodeposition efficiency of the modified carbamic acid mat was the highest, and the recovery efficiency of Cu²⁺ reached 99.99 %. Since there are lone electron pairs on the amidoxime group, amide group and carboxyl group supported by the modified amidoxime carbon felt at the same time, the adsorption site of Cu²⁺ can be increased, so the recovery efficiency of Cu²⁺ can be greatly improved.The use of modified amidoxime carbon felt in this study provides a new way to recover copper from copper wastewater.