| Bisphenol S?BPS?is widely used in many areas,but it could cause water pollution problems in the environment during production and use.As an endocrine disruptor,BPS could cause human or animals estrogen abnormalities,obesity,endocrine dysfunction and other diseases.Therefore,it is necessary to find an efficient adsorbent to remove BPS from aqueous solution.In this paper,?-cyclodextrin/epichlorohydrin polymer??-CDP?and magnetic?-cyclodextrin/epichlorohydrin polymer??-CDP@Fe3O4?were synthesized with epichlorohydrin as a cross linking agent in aqueous solution of sodium hydroxide and were used as adsorbents for BPS removal form aqueous solution.The adsorption mechanism of BPS on these two adsorbents was studied.The main contents were as follows:?1?The adsorption capacity and adsorption rate of?-CDP respectively 73.6mg·g-1 and 73.6%under the experimental conditions(T=298 K,pH=5.4,m=0.05 g,C0=100 mg·L-1,V=50 mL,t=60 min)in single factor tests.The adsorption capacity and adsorption rate of?-CDP respectively 73.6 mg·g-1 and73.6%under the experimental conditions(T=298 K,pH=5.4,m=0.05 g,C0=100 mg·L-1,V=50 mL,t=60 min)in single factor tests.The adsorption capacity and adsorption rate of?-CDP@Fe3O4 respectively 73.6 mg·g-1 and91.1%under the experimental conditions(room temperature,pH=5.5,m=0.075g,C0=50 mg·L-1,V=50 mL,t=150 min)in single factor tests.?2?The both adsorption process of BPS on?-CDP and?-CDP@Fe3O4followed the Pseudo-second-order model and chemisorption was the rate controlled step.?3?The both adsorption of BPS by?-CDP and?-CDP@Fe3O4 was fitted by the Langmuir adsorption isotherm model.It suggested that the adsorption occurred on the surface as a monomolecular layer.The adsorption of BPS by?-CDP was a spontaneous and exothermic process.?4?Desorption experiments showed that the two adsorbent materials could maintain effective adsorption performance after six regeneration cycles,but it was easier to separate?-CDP@Fe3O4 from BPS solution by magnet.?5?The optimum adsorption conditions of the dynamic experiments that space velocity was 20 h-1 and initial concentration was 100 mg·L-1 of BPS.Under these condition,compared with the penetration time?30 h?and saturation time?56 h?in the initial adsorption,the penetration time?24 h?and saturation time?49 h?after two times of dynamic regeneration were not significantly shortened.At space velocity of 20 h-1,?-CDP@Fe3O4 as the stationary phase adsorbed different initial concentrations of BPS solution with 50 mg·L-1,100 mg·L-1 and 150 mg·L-1 and by thomas dynamicadsorption model calculation the adsorption capacity was 81.4 mg·g-1,93.8 mg·g-1 and 98.9 mg·g-1 respectively.?6?The mechanism of adsorption of BPS for?-CDP and?-CDP@Fe3O4 showed that the driving force was the formation of hydrogen bonds between hydroxyls of BPS and?-cyclodextrin.BPS entered the cavity of?-cyclodextrin by virtue of the hydrophobic interaction and hydrogen bonds. |
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