A novel copper wire assisted activated carbon electrode in capacitive deionization for water hardness removal

Abstract

The need to apply electrical energy in water hardness removal technologies has led to great expenses for saline water treatment due to high energy consumption. This study presents a novel approach to capacitive deionization (CDI) using Copper Wire-Assisted Activated Carbon (CWA-AC) electrodes which offer superior water hardness removal efficiency and reduced energy consumption compared to conventional electrodes. CWA-AC electrodes were fabricated by coating activated carbon and carbon black powder onto copper wire surfaces using epoxy adhesive. They demonstrated promising capabilities in water hardness removal from both natural and simulated water. Systematic experimentation involving the variation of activated carbon weight and copper wire length achieved the optimal CWA-AC electrodes at 100 mg of activated carbon and a 5cm length of copper wire. These electrodes exhibited an impressive electrosorption capacity of 10.25 mg/g when treating a calcium chloride solution having a concentration of 80 mg/L. In practical application, the optimal CWA-AC electrodes effectively reduced the hardness of tap water from 287.9 ± 1.2 to 158.6 ± 4.2 mg/L (achieving a removal efficiency of 44.91%) while consuming the energy of 0.174 ± 0.013 kWh/m3 only. This research highlights the potential of CWA-AC electrodes in CDI for hardness removal efficiency and reduced energy consumption compared to conventional electrode designs which achieved water hardness reduction from 287.9 ± 1.2 to 196.2 ± 6.8 mg/L (a removal efficiency of 31.85%), even though consuming more energy of 0.226 ± 0.016 kWh/m3. These findings suggest a promising path for enhancing the effectiveness and sustainability of desalination processes using CDI.