Efficient Cr(VI) Removal Using Layered Double Hydroxides as Anode Materials in Asymmetric Flow-Electrode Capacitive Deionization

Flow-electrode capacitive deionization (FCDI) is an advanced technology that enables efficient, continuous wastewater treatment. In order to recover Cr(VI), a cost-effective FCDI system was created in this work utilizing activated carbon (AC) and layered double hydroxides (LDH). The findings show that the LDH anode material has a high degree of inherent resistance and that Cr(VI) in wastewater is efficiently immobilized into the LDH flow electrode. At an ideal voltage of 1.2 V, the LDH-AC-FCDI system operating in isolated closed-cycle mode demonstrated an outstanding removal efficiency of up to 99% for Cr(VI). The system showed selective Cr(VI) adsorption and maintained a 98% removal efficiency when used on wastewater with 500 mg L–1 of chloride ions at a voltage of 2.4 V. The evaluation of Cr(VI) removal efficacy in low-concentration wastewater treatment can be also effectively addressed using the LDH-AC-FCDI system. These findings provide novel insights into optimizing the application of FCDI for selective ion recovery processes.