Preparation and Characterization of Hydrophobic Flat Sheet Membranes Based on a Recycled Polymer

Abstract

Abstract In this work, we used a recycled low-density polyethylene (LDPE) in order to prepare flat sheet membranes with different polymer concentrations (5 and 10%). The used chemical method for the membrane's preparation is the phase inversion. After obtaining the membranes, we characterized them by atomic force microscopy (AFM) and scanning electron microscopy (SEM) to study their structure and surface characteristics. Based on the SEM images, our membranes have a dense skin layer. In addition, we observed a decrease in the porosity with the increase in the polymer concentration. When the polymer concentration increases from 5 to 10% the porosity decreases from 35.54% to 20.28%. Furthermore, we remarked significant changes in the contact angle and the surface roughness with the increase of the polymer concentration. The roughness increases from 363 to 577 nm for the same evolution of the polymer concentration. These high values of roughness imply obtaining values of contact angles greater than 90° and hydrophobic membranes, which is beneficial for the membrane distillation. Furthermore, the use of our membranes in vacuum membrane distillation (VMD) experiments showed a permeate flux up to 1.503 kg/hm2; for the membrane with 35.54% of porosity and 5% of polymer concentration.