Study On Foam Separation Of Metal Ion From Its Aqueous Solution

Foam separation is one of the rapidly developed new separation techniques in decades. In this dissertation, foam separation of metallic ions in aqueous solution was investigated.The optimal separation conditions of copper ion and cadmium ion in aqueous solution were determined by comparing the influence factors. By using the orthogonal experiment and comparison of variables in each factor, the optimal conditions of nickel ion were obtained.The factors to affect the foam separation, such as initial concentration, surfactant concentration, type of surfactant, pH value, amount of CTAC, air flow rate, time and temperature et al, were studied. In addition, some changes in apparatus such as adding the fluid circling pipe and the damping plate were made to improve the separation efficiency.The results showed that the enrichment and recovery ratio increased with the decreasing of initial concentration. The anion surfactant is much better than cation surfactant to separate metal ions from its aqueous solutions by means of foam separation. Increasing the air flow rate and separation time, the enrichment decreased and the recovery increased. The expected separation efficiency was not reached by adopting the fluid circling pipe and the damping plate in experiments. Under the optimal conditions, the enrichments of copper ion, cadmium ion and nickel ion can reach 5.39, 6.19, 5.13 respectively. The recovery ratios were 30.8%, 36.26%, 43.03% respectively.All of the above mentioned experimental results, which were necessary to built foam separation model, were also explained and discussed by using the theory of adsorption and foam separation.