MODIFIED NANOFILTRATION MEMBRANE WITH GRAPHENE AEROGEL CONTAINING POLYETHYLENEIMINE TO REMOVE LEAD FROM WATER: EXPERIMENTAL AND SIMULATION STUDY

Nanofiltration membranes are used to remove heavy metals, especially lead ions, which are considered as one of the most important pollutants in drinking water, Liu et al. (۲۰۱۱).In recent years, the use of nanomaterials such as carbon and graphene oxide has received much attention to modify the surface of the membrane, Jawed et al. (۲۰۲۰). In a study by Zhang et al. graphene oxide was crosslinked by polyethyleneimine (PEI) molecules with graphene oxide (GO) nanosheets and then modified with hyper-branched polyethyleneimine (HPEI) for stable design and surface charge of the active layer (GO). The membrane showed high rejection for heavy metal ions, Nasir et al. (۲۰۱۹), which indicates the high capacity of (GO) in water treatment processes, Zhang et al. (۲۰۱۸). Aerogels due to their very high porosity and low-density structure, have been used in catalysts and adsorption processes. The nanofiltration process is complex, so developing models that can quantify and simplify transfer phenomena in the membrane is important. Cao et al (۲۰۱۸) investigated the effect of flow hydrodynamics and concentration polarization on the biological fouling of nanofiltration membranes by using computational fluid dynamics. They considered the effect of concentration polarization on the membrane surface and compared the results with the experimental data. They found that the model predicts good results. In this research, for the first time, graphene aerogel containing polyethyleneimine has been used as an improving agent, by using the capacity of aerogel and graphene simultaneously for surface modification of nanofiltration membranes. Then the process is simulated using the CFD۲technique. Employing the CFD technique to simulate the nanofiltration process presented good results.