Purifying ⁶⁰Co-containing low-level radioactive wastewater via electro-deionization with zirconium phosphate ion-exchange resins.

In this study an electro-deionization (EDI) technology employing α-zirconium hydrogen phosphate (α-ZrHP) inorganic ion-exchange resins is investigated for purifying ⁶⁰Co-containing low-level radioactive NaNO₃ wastewater. Special focus is given to the scale-up effects from lab to miniature pilot-scale operation. The influence of key process parameters including voltage, solution flow rate and volume ratio, as well as feed concentration on NaNO₃ desalination performance and water dissociation behavior was studied. Under optimal conditions, the system achieved a treatment capacity of 9.53 L/h, a water recovery rate of 81.8%, a specific energy consumption of 1.73 kWh/m³ , and a removal rate exceeding 99% for both NaNO₃ and Co (NO₃) ₂. The EDI process demonstrated superior performance compared to electrodialysis (ED), and the transfer behavior of Co²⁺ was revealed. The treatment of genuine low-level radioactive wastewater resulted in a 97.55% removal of 60Co β-radioactivity. The results confirm that the inorganic resin-packed EDI system, leveraging the exceptional radiation resistance of the inorganic material and efficient desalination capability, is a promising technology for radioactive wastewater treatment. The successful lab to miniature pilot scale-up provides valuable insights for future industrial implementation of this technology.