Reuse solution of hardness industrial circulating cooling water: Targeted ion-selective electro-adsorption by functionalized electrode

Abstract

A low-cost, efficient and environmentally friendly hardness ion selective electro-adsorption system for high-hardness industrial circulating cooling water reuse was constructed to simultaneously realize a high salt removal rate and hardness ion (Ca2+ and Mg2+) selection. Multiply modified graphite carbon felt (GCF) materials for both negative and positive electrodes were proposed simply and economically, and an electro-adsorption system for hardness control was assembled. The multiple modified GCF (GCFM) materials were characterized by SEM, BET and FT-IR and the electrochemical performance was tested by CV and EIS; surface properties were studied by Zeta potential; the hardness ion removal selectivity and operational stability of the electro-adsorption system were tested. Hydrophilic functional groups were introduced in GCFM electrode, GCFM exhibited a large microporosity and demonstrated stable electrochemical performance in aqueous with a specific capacitance. The hardness ion selective electro-adsorption system achieved an adsorption capacity of 58.05 mg/g per circle for calcium ions and 31.03 mg/g for magnesium ions, indicating the superior hardness ion selectivity. In the circulating cooling water at the electro-adsorption stage, the ion removal performance was over 42.1% and maintain in good stability, GCFM electrode showed excellent deionization performance and demonstrated the application potential of hardness ion selective electro-adsorption system.