Reuse of municipal wastewater via membrane capacitive deionization using ion-selective polymer-coated carbon electrodes in pilot-scale

Abstract

This study investigated membrane capacitive deionization (MCDI) at a pilot-scale using ionselective polymer-coated carbon electrodes for wastewater reuse. Several issues have been addressed to verify the suitability of MCDI for wastewater reclamation: electrosorption 2 performance, removal efficiency and selectivity of ions present in wastewater, optimization of operating conditions, and performance degradation in long-term caused by the accumulation of organic contaminants. The coated electrodes had better adsorption capacities and charge efficiencies than the conventional MCDI system, which was attributed to their low electrical resistance induced by the thin coated layer. The pilot-scale MCDI test cell involved 50 pairs of anion-and cation-selective electrodes and achieved good removal efficiency of ions from the wastewater effluent, particularly for problematic charged impurities, such as nitrate (NO3 -) (up to 91.08% of NO3was removed). Increasing the flow rate and reducing the applied potential were shown to be efficient for achieving better water quality by enhancing the NO3selectivity. Last, the 15 d operation showed good reproducibility in electrosorption and regeneration for the coated electrodes, despite the fact that high concentrations of organics were contained in the wastewater feed solution (12.4 mg/L of dissolved organic carbon).

Characteristics and Vanadium Adsorption Performance of Resin/Carbon Composite Electrodes in Capacitive Deionization

“…Activated carbon (AC) , , carbon nanotubes (CNTs) , ordered mesoporous carbon , carbon aerogels , , carbon nanofibers , and graphene are widely used in CDI systems due to their high specific surface area, suitable pore structure, and good chemical stability. Traditional CDI with single carbon material as electrodes shows poor adsorption selectivity for ions, because these materials have no or weak ion selectivity , . Thus, CDI was only applied in desalination of seawater or brackish water for a long time.…”

Water reclamation and reuse

“…Municipal wastewater treated by wetlands in the Atacama Desert demonstrated their efficacy in water reuse for cultivating cut flowers using a lab-scale aeroponic cultivation system under extremely arid conditions (Vera-Puerta, Olave, Tapia, & Chavez, 2019). Kim et al (2019) evaluated the feasibility of MCDI using ion-selective polymer-coated carbon electrodes for practical wastewater reclamation at a pilot scale. The MCDI test cell consisting of 50 pairs of anion-and cation-selective electrodes achieved substantial removal efficiency of unwelcoming impurities, such as NO 3 -(91.08% removal efficiency), from wastewater effluent.…”

“…Kim et al (2019) evaluated the feasibility of MCDI using ion‐selective polymer‐coated carbon electrodes for practical wastewater reclamation at a pilot scale. The MCDI test cell consisting of 50 pairs of anion‐ and cation‐selective electrodes achieved substantial removal efficiency of unwelcoming impurities, such as NO 3 ‐ (91.08% removal efficiency), from wastewater effluent.…”

Physico‐chemical processes

“…K + was released first, followed by Na + and Mg 2+ because of different physiochemical properties. Kim et al (2019b) conducted a pilot study of MCDI through utilizing ion-selective polymer-coated carbon electrodes for water reclamation. The coated electrodes improved the MCDI system by enhancing the adsorption capacities and charge efficiencies.…”