Enhancement of styrene adsorption and desorption performance on zeolite by acid,alkali and salt modification
Desorption of styrene during adsorption processes is a big challenge due to its tendency to polymerize on adsorbent materials,how to realize the effective desorption of styrene is a well-recognized issue in the field of volatile organic compounds(VOCs)pollution control.In this study,a kind of high silicon zeolite was used to explore the effect of different modifications with nitric acid,sodium acetate,and sodium sulfate on its performance of styrene adsorption and desorption.The results indicated the polymerization behavior of styrene in the process of absorption and desorption on the modified zeolite were effectively reduced and the desorption performance for all samples increased significantly.The optimal concentrations for sodium sulfate,sodium acetate,and nitric acid modifications were 1,0.05 and 1 mol·L-1,respectively.The zeolite modified with 0.05 mol·L-1 CH3COONa exhibited the best styrene desorption performance with an increase in desorption rate from 80％to 90％,and the absorption capacity could reach 122 mg·g-1,and over 85％of its initial adsorption capacity could be maintained even after ten cycles.Characterization of the samples revealed that the acidic sites of zeolites could intensify the polymerization of styrene.Zeolites modified by nitric acid and sodium acetate showed the decrease in acidic strength and reduction of acidic sites,thus,the polymerization of styrene decreased and the desorption performance increased.For zeolites modified by sodium sulfate,both the enhancement of the pore confinement and the reduction in acidic sites promote the desorption of styrene.
styrenepolymerizationzeolitemodificationadsorption and desorption
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