Electrodeionization of low-concentrated multicomponent Ni2 +-containing solutions using organic–inorganic ion-exchanger

Abstract

Organic–inorganic ion-exchangers have been obtained by modification of gel-like flexible resin with zirconium hydrophosphate, which form both single and aggregated nanoparticles in the polymer matrix. Insertion of the inorganic constituent into the resin up to 40 mass % was found to increase electrical conductivity of the resin from 0.2 to 0.7Ω−1m−1. Total ion-exchange capacity also increases from 600 to 1800molm−3. The organic–inorganic ion-exchanger with the highest amount of the inorganic constituent was used for electrodeionization processes to remove Ni2+ from low-concentrated solutions containing also hardness ions and organic substances. The “once-through” processes have been developed based on ion transport investigation under variation of the initial pH, concentration, and flow velocity of the solution being purified. Residual Ni2+ content in the solution was 0.7–0.9ppm, the energy consumptions have been estimated 0.4–0.7kWh per 1m3. The organic–inorganic ion-exchanger was found to demonstrate stability against fouling with organic substances as opposed to the unmodified resin.