Membranes of polyamide 6/clay/salt for water/oil separation

Abstract

In this work, polyamide 6 membranes (PA6) and nanocomposites with 1.0 wt%, 3.0 wt% and 5.0 wt% of montmorillonite clay (MMT) were obtained, adding inorganic salt. The MMT clay was characterized by x-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The membranes were characterized by XRD, FTIR, scanning electron microscopy (SEM), contact angle (CA), flow measurements (FM) and yield. The viscosities of the solutions decreased with the increasing percentage of clay. By means of the XRD, it was seen that the nanocomposites membranes suggest an exfoliated and/or partially exfoliated structure. From the results of the FTIR the bands obtained in the PA6 membranes and its nanocomposites remained practically unchanged, as there was an increase in the clay content. By SEM, it was observed that the gradual addition of clay in the membranes provided an increase in the number and size of pores. By means of the CA, it was verified that the nanocomposites membranes presented smaller angles when compared to the PA6. The water-oil separation tests of the membranes, regardless of the pressure used, indicated a significant reduction of permeate oil with promising yields above 87%, presenting potential for the treatment of wastewater contaminated by oil.