Fabrication Of Pervaporation Membrane For Pyridine Removal From Water

Pyridine,as one of the main pollutant of industrial waste water of pyrethroid pesticide productive processes,its strong toxicity and hard degradation pose serious threat to environment and human health.Considered from its industrial value and environmental hazards,separation and recovery of pyridine are of great significance.Pervaporation,as a development and promising new type of membrane separation technology,is characterized by easy operation,energy saving and no secondary pollution compared with the traditional separation process,as for which it has attracted more attention.The purpose of this work is to prepare membranes with good performance for recovery of pyridine.Pervaporation process is based on the different selectivity of membrane materials towards the various components in the mixtures,so the most researches focus on the preparation and modification of the membrane.According to the principles of the solubility parameter,we choose poly（ether-block-amide）（PEBA）as the basic material.The novel membranes used for recovery of pyridine from water were prepared by modifying PEBA.The membranes were characterized by X-ray diffraction,atomic force microscopy,scanning electron microscope and contact angle goniometer,and pervaporation properties were investigated systematically.In order to improve the separation performance of PEBA membrane,Mo S₂ and C u₂O nanoparticles were chosen as the filler,and the mixed matrix membranes of PEBA were prepared for recover pyridine from wastewater.It can be observed that the membrane is dense with no appreciable voids and dispersed uniformly in the PEBA matrix from the images of SEM.The XRD show that the filler is only physically blended with the polymer matrix.The result from the TGA image indicates that the incorporation of filler into PEBA membranes is beneficial for improving thermal stability of PEBA membrane.The results indicated that the separation factor and flux of filled PEBA membranes both increased with an increasing of feed temperature.It shows that the flux increases,however,the separation factor decreases with an increasing of pyridine concentration in the feed solution.The separation performance of both the Mo S₂ filled PEBA and C u₂O filled PEBA composite membrane with the content10.0 wt%and 6.0 wt%,respectively,were the best.Under the pyridine concentration of 1.0wt%and at 30℃,the pyridine flux were 8.28 g m^-2h^-1 and 8.45 g m^-2h^-1respectively,and the corresponding separation factor of pyridine were 10.22 and 11.18.For further improving the the separation performance of PEBA membrane,high hydrophobic carbon nanotubes（CNTs）and PEBA blending membranes were prepared.The SEM show that the filler dispersed uniformly in the PEBA matrix.The result from the TGA image indicated that the thermal stability of the hybrid membrane was improved effectively.The pervappration results show that the separation factor increased with an increasing of CNTs content,arrived at a maximum when the CNTs content is 5.0 wt%,then decreased with the further increasing of CNTs content.The CNTs and PEBA blending membranes show encouraging separation performance with a pyridine permeation flux of 15.16 g m^-2h^-1and separation factor of 11.78 at 30℃at the pyridine content 1.0 wt%.