Activated carbon nanoparticles entrapped mixed matrix polyethersulfone based nanofiltration membrane for sulfate and copper removal from water

Mixed matrix activated carbon nanoparticles (ACNPs) embedded polyethersulfone based nanofiltration membranes were prepared by solution casting technique. SEM images show that utilization of nanoparticles in the membrane matrix causes a decrease of the size of the channels in both top and sub layers. SOM images show a uniform nanoparticle distribution for the prepared membranes. SOM images also show agglomeration of nanoparticles at high additive concentrations. The surface images show a reduction of roughness for membranes filled with ACNPs. The flux decreases at 0.05 wt% nanoparticles loading rate and then increases again by an increase of the nanoparticles dosage from 0.05 to 0.1 wt%. The flux then decreases again at a nanoparticles ratio from 0.1 to 1 wt%. According to the performance test, the membrane with 0.5 wt% nanoparticles indicated the highest sulfate (95%) and Cu (97%) ions removal. The water contact angle was found to decrease from 54° to 43° by increasing the ACNPs concentration. This is assigned to a decrease of the membrane surface roughness due to migration of nanoparticles to the membrane surface during the fabrication process. The water content in the membrane and the porosity were also improved by increasing the nanoparticles ratio up to 0.1 wt%, but decreased for higher additive concentrations. The tensile strength of the membranes was enhanced by utilizing a nanoparticles ratio up to 0.05 wt%, but showed a decreasing trend for higher nanoparticles concentrations. The decrease of the flux ratio (J/Jo) was measured to be 5% for the modified membrane containing 0.5 wt% ACNPs and 63% for the pristine membrane.