Study Of Elimination Of Trace Cobalt In The Water By Foam Separation

Foam separation is known to have potential for separation and concentration of the material of surface activation with the medium of bubbles. It has many property, such as simple craft, low cost, small area of occupation of land, meeting the changes of the quality and flow of the water and recovering many valuable components at the same time. Foam separation has very good development prospect because of its good effect of separation when it separate of trace components with a rank of 10^-6 mg.L^-1.In this paper, trace of cobalt in the water is separated by the use of dissolve gas foam separation equipment. The influences of types of surfactant, pH value, the mole ratio of aluminium to cobalt, the concentration of SLS(sodium dodecyl sulphate)and gas flux were reviewed. When the concentration of cobalt ion is 10 mg·L^-1, the concentration of sodium dodecyl sulphate is 10 mg.L^-1, the mole ratio of aluminium to cobalt is 1:1, pH value is 11, gas flux is 300 L.h^-1, the removal efficiency is 97.61%.According to the similar physical behaviors of foam separation process and chemical reaction process, the equivalent chemical reaction constant was introduced, then the macroscopical dynamics of using foam separation to remove cobalt ion from water was studied. The result indicated that the process of foam separation could be regarded as first order reaction, which equivalent speed constant is k = 0.491 min^-1. Through measuring and analyzing the distribution of residence time, the average residence time is t_m =11.28min, variance isσ_θ² = 0.694. The distribution density function of residence time is confirmed combined with the relevant experiments. The influence factors about the foam separation process removal efficiency of fluid flowing are studied. The mathematic model of this process was analysed and discussed combined with the residence time distribution function and variance.