Study On The Electro-regeneration For Aluminum-type Mixed Resins

The theory, research and development of electro-regeneration for ion-exchange resins are summarized systematically. According to the principle of broadening the application range of electro-regeneration, improving the working conditions, decreasing the cost of operation and rising the use factor of resource and protecting the environment, the electro-regeneration technology of aluminum-type strong acid and week alkali mixed resins is tested.In this paper, the principle of the deep electro-regeneration for aluminum-type strong acid and week alkali mixed resins is studied firstly, and then the feasibility is confirmed by the self-made test device. The effects of regeneration voltage, time and flow velocity of AI(OH)₃ suspension on the electro-regeneration are investigated. The optimum working parameters for deep electro-regeneration device are obtained by the parallel tests as follows: the regeneration voltage is 60V, the regeneration time is 4h and the flow velocity of Al(OH)₃ suspension into regeneration chamber is 0.2 ml·s^-1. Under this condition, 100ml regenerated aluminum- type mixed resins can treat 5000ml tap water (about 200μs·cm^-1), and product water quality is good, the conductance maintain 1μs·cm^-1 below with 4200ml water treatment. The contrast experiments also indicate that the electro-regeneration effect of aluminum-based mixed resins is better than general mixed resins; the electro-regeneration effect of aluminum-based cation resins closes to the chemical regeneration, while the electro-regeneration effect of anion resins even surpasses the chemical regeneration.Considering of decreasing the energy consumption, the device of electro-regeneration is improved, and the feasibility of the two steps regeneration and the regeneration by the sacrifice of electrode for aluminum-type mixed resins are studied. The mechanisms of the two regeneration processes are analyzed; the influencing factors of regeneration are also discussed, and then the best operating condition of the two steps regeneration installation is determined as follows: the regeneration voltage is 60V, the regeneration time is 4h and the flow velocity of two chambers is 0.2 ml·s^-1. The tests results demonstrate that the circulation regeneration effects of the two techniques are stable and repeatable. However, the regeneration effect of mixed resins is inferior to the deep electro-regeneration.