| Surfactant is a ubiquitous substance in aquatic environment owing to its popular use.It has the characteristic of enwrapping insoluble substances and forming colloids,and so is the carrier of insoluble and environmental hazardous substances to exist and transfer in water body.In the disposal process of surfactant wastewater,flocculation technology is usually used as a pretreatment method.The flocculation process of this kind of wastewater is very complicated because of its complicated components and unconstant characteristics.To control its behaviors in disposal processes,the coagulation characteristics of anionic surfactant sodium dodecyl benzene sulphonate(SDBS)micellar solution with different dosage of alum sulfate or alum sulfate were investigated respectively in this study.Combined with the change of Zeta potential and surface tension measurements,the preferable stoichiometric proportion in each case was investigated.With the experimental evidences,the preferable stoichiometric proportion between Al and SDBS,Fe and SDBS was about 2.5×10-3mol/L and 3×10-3mol/L respectively.Furthermore,based on several coagulation characteristics observed in samples with different pH,the preferable stoichiometric proportion between Al and SDBS,Fe and SDBS were also investigated,combined with the change of Zeta potential and surface tension measurements.Results shows that,(1)Both Al2(SO4)3-SDBS system and FeCl3-SDBS system are sensitive to pH condition.(2)In Al2(SO4)3-SDBS system,under the weak-acidic pH condition about 5,the equilibrium zeta potential is near zero and the peak value of surface tension is higher,and the preferable molar ratio of Al to SDBS is about 0.15.(3)In FeCl3-SDBS system,under the weak-acidic pH condition about 4,the equilibrium zeta potential is near zero and the peak value of surface tension is higher,and the preferable molar ratio of Fe to SDBS is about 2.5.(4)When the molar ratio of Al to SDBS is raised to around 3,the coagulation reduce gradually. |
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