Wastewater Treatment and Water Quality Assessment Through Electrochemical Approaches

Abstract

The protection of water resources is becoming one of the most critical issues afflicting people globally. Novel, robust, efficient, and environmentally compatible technologies for the treatment of wastewater and the analysis of water quality are urgently required. Fortunately, with the development of electrochemistry and new materials, promising and environmentally benign approaches for the treatment of wastewater and the assessment of water quality are currently available. An advanced and efficient approach known as EDI was developed for the continuous separation and recovery of Cr(III) and Cr(VI). Firstly, we developed a new analytical method, which combines UV-Visible spectroscopy and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), for the determination of the concentrations of both Cr(VI) and Cr(III) in a mixed solution, and for monitoring the EDI process. Secondly, we determined the limiting current and systematically studied the effects of different applied currents on the removal of Cr(VI) as well as on the recovery of Cr(III) and Cr(VI). Thirdly, the influence of the level of saturation of the ion- exchange resins was assessed in terms of both removal efficiency and energy consumption. The use of fresh ion-exchange resins for the EDI process were initially found to be very effective for the removal of both Cr(VI) and Cr(III). Both resins became increasingly saturated with each subsequent cycle, resulting in a gradual lowering of the cell voltage. The continuous and highly efficacious removal of highly toxic Cr(VI) (> 99%), and low energy consumption make the EDI process attractive for the separation and recovery of Cr(VI) and Cr(III).