Electrochemical Oxidation of Phenol Released from Spent Coordination Polymer Impregnated with Ionic Liquid

Abstract

Coordination polymer (CP)-type adsorbents impregnated with ionic liquids that are used to remove phenol from wastewater must be regenerated. A simple washing of the adsorbent releases about 70% from the spent adsorbent. In order to increase and study the phenol release, an electrochemical method was used. For this purpose, an electrochemical commercial graphite electrode was used as the working electrode, and the electrolyte support was a 3% NaCl solution. During the electrochemical investigation, the spent CP was immersed in a saline solution. The PH content in the electrolyte affected the direct electrooxidation (EO); the formation of BQ appeared to be accelerated by a lower concentration and a slower release of PH. After 90 min, an efficiency of PH electrooxidation (EOPH) of 36.22% from Cu-PA and EOPH of 42.14% from Cu-PA-IL, respectively, was achieved. These results were significantly higher than the EOPH of the solution resulting from washing the wasted adsorbent with a saline solution (22.58%). This work highlights the potential for the simultaneous electrooxidation of desorbed PH and the recovery of spent adsorbent in this situation. The number of cycles in which the adsorbent can be used without losing its absorbance ability is three.

Keywords

• electrochemical regeneration
• pollutants
• phenol
• coordination polymers
• electrochemical impedance spectroscopy (EIS)