Preparation And Pervaporation Performance Of PGS/PAM Hybrids And Their Membranes For Seperating Xylene Isomers Mixtures

The application of pervaporation in organic mixture separation is of energy-saving and environment-protecting significance. In this paper, preparation and pervaporation of Palygorskite/Polyacrylamide(PGS/PAM) inorganic-organic hybrid membranes for separating xylene isomers were investigated. The interactions between hybrid membranes and xylene isomers and the relationship between them and pervaporation performance had been studied. And we also discussed by the pervaporation dissolution-diffusion mechanism of pervaporation performance.Palygorskite/Polyacrylamide hybrid materials were synthesized via intercalation polymerization initiated by redox initiator consisting of modified PGS and Ce⁴⁺, and used as membranes for the separating xylene isomers mixtures by pervaporation. The ¹H NMR and FTIR spectrums suggest that a conjunction of electrovalent bond PGSΘ♂ NH₃R existed in the PGS/PAM hybrid. The TGA and XRD curves proved the exist of the interaction between inorganic and macromolecule.The effects of the PGS content in the hybrid membranes and feed temperature or feed concentration on the pervaporation performance of the hybrid membranes were investigated. The pervaporation performance of hybrid membranes was superior to pure PAM membrane. And as the PGS content in the hybrid membrane was 1.92wt%, the maximum value of the separation factor a reveals. The viewpoint that the competition of the affinity caused by the secondary adsorption and the congregator of PGS granules caused by the superfluous inorganic ingredient was used to interpret ours results. At the same, time the configuration of hybrid membranes was another important factor to results.In the increasing of feed temperature, the variety of the permeate flux J of hybrid membranes was accorded with Arrhenius equation. The variety of Permeation Activation Energy with feed concertration was accorded with the control factor which was received by dissolution- diffusion mechanism.For different concentration of feed mixtures, it was observed that in p-/m-xylene mixture the selectivity of membrane was changed with the increasing of p-xylene concentration. In this course, the control factor was changed along with selectivity in dissolution- diffusion mechanism. The essential reason was the effect of interactions between xylene isomers on hybrid membrane and feed mixtures.