The interaction between a cationic dye Methylene Blue(MB) and an anionic surfactant sodium dodecyl sulfate(SDS) with the presence of Cd2+ was investigated spectrophotometrically in a certain concentration range.The spectrophotometric measurements of dye-metal ion-surfactant system were carried out.The results indicated that the SDS concentration had a significant influence on the dye spectrum,while the addition of Cd2+ hardly caused change of the maximum value of absorbance.According to this observation,we concluded that electrostatic and hydrophobic interaction between dye and surfactant occurred up to a certain level,and the homo-ions Cd2+ almost exerted no effect on the dye-surfactant complexation,establishing a theoretical foundation for simultaneous removal of organic dye and heavy metal using foam fractionation.Meanwhile,the effects of their interaction on foam performance were investigated.The results showed that the addition of Cd2+ favored the tendency to ameliorate foam properties just contrary to MB.The feasibility of foam separation for dye and heavy metal removal from simulated wastewater was also confirmed using a continuous foam fractionator.In the simultaneous removal process,with the initial SDS concentration ranging from 0.5 to 5.0mmol/L,the maximum removal efficiencies of MB and Cd2+ were obtained as 99.69% and 99.61%,respectively.The enrichment ratios were reduced from24.34 to 7.65 for MB and from22.01 to 3.35 for Cd2+.
To separate zinc ions from aqueous solution efficiently, micellar-enhanced ultrafiltration(MEUF) of hollow ultrafiltration membrane was used with sodium dodecyl sulfate(SDS) as surfactant.The formation of micellar and the adsorption mechanism were investigated, including the influence of the ratio of SDS to zinc ions on the micelle quantity, the micelle ratio, the gross adsorptive capacity, the rejection of zinc ions and the adsorption isotherm law. The results show that the rejection rate of zinc ions reaches 97% and the adsorption of zinc ions on SDS conforms to the Langmuir adsorption isotherm and the adsorption is a chemical adsorption process.
