| Removal of heavy mental ions or salt removing in culture broths or industrial wastewater is an important unit of biochemical engineering. This paper studied the technology of foam separation for removing mental ions in aqueous solution and the results were as follows:1. DBSA was screened out as the surfactant for the removal of trace Fe3+, Cu2+, Na+ in the aqueous solution.2. The two-stage process for removing Fe3+ was firstly studied. Orthogonal experiments showed the optimum conditions of the first stage were pH 4.0, gas flow rate of 0.05 m3/h, surfactant concentration of 0.16 g/L and load volume of 1000 mL, with the enrichment ratio and removal rate were 9.86 and 98.63%, respectively; the optimum conditions of the second stage were pH 2.5, gas flow rate of 0.05 m3/h, surfactant concentration of 1.4 g/L and load volume of 1200 mL, with the enrichment ratio and removal rate were 4.67 and 99.5%, respectively. The residual liquid of the second stage could be used as bulk solution for the first stage, with the total enrichment ratio and removal rate were 46.05 and 98.14%, respectively.3. The optimum conditions of orthogonal experiments for removing Cu2+ were pH 3.0, gas flow rate of 200 mL/min, surfactant concentration of 0.2 g/L and load volume of 1200 mL, with the enrichment ratio and removal rate were 21.3 and 95.2%; EV could cover for E in qualitative analysis.4. Further researches were done respectively by taking Fe3+, Cu2+ and Na+ in the aqueous solution as the simulated system. At the same situation, the higher the metal ion valence was, the larger the removal rate, and the smaller the enrichment ratio.5. Kinetics model of foam separation for removing Fe3+ was established and the equations of removal rate and enrichment ratio were found as follows:Compared with the experimental datum, the kinetics model could well reflect the characters of foam separation for removing Fe3+. At low gas flow rate, the model datum fitted well with the experimental datum when it could form stable foam. |
