Characterization and effect of sodium dodecyl sulfate on polysulfone/polyethylene glycol membrane for Pb (II) ions removal

The release of heavy metals from agriculture activities and industrial effluents into the water is causing concern on a worldwide scale since it poses a major risk to both people and ecosystems. Chemical precipitation is a common technique used in the treatment of heavy metals from water. However, the technique uses a huge amount of chemicals and generated hazardous sludge that needs to be treated further. Therefore, in this study, the potential of membrane filtration is explored as an alternative treatment of heavy metals because of its environmentally-friendly property and it does not cause secondary pollution. For methodology, membrane was developed using wet phase inversion method that incorporated a suitable amount of polysulfone (PSF) with different concentration of sodium dodecyl sulfate (SDS) namely M1=pure; M2=0.5 wt% SDS; M3=1.0 wt% SDS; M4=1.5 wt% SDS; M5=2.0 wt% SDS, into dimethylacetamide (DMAc). The physical characterisation was analysed by contact angle, water uptake, porosity and mean pore radius. Meanwhile, the chemical characterization was analysed by Fourier Transform Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR), Field Emission Scanning Electron Microscopy (FESEM) and Thermogravimetric Analyses (TGA). In addition, the membrane performance was evaluated in terms of permeation flux and rejection by dead-end filtration cell. The Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) 5110 Agilent model was used to measured Pb (II) ions concentration. The finding showed, M4 membrane (1.5 wt% SDS) demonstrated highest Pb (II) ions rejection (90.52%) due to the existence of macrovoids and porous structure as shown by FESEM analyses. Furthermore, these results were supported by lower contact angle (47.92o), higher water uptake (43.58%), higher porosity (85.21%) and lower mean pore radius value (6 nm) for M4 membrane. Fouling mechanism model demonstrated that the complete blocking was matched with the experimental data indicating porous blockage occured on the absorption of Pb (II) ions on membranes surface. As conclusion, membrane M4 with composition of 1.5 wt% concentration SDS showed the optimum membrane filtration to remove Pb (II) ions for water treatment in lab scale. The limitation of the experiment is it needs to be further conducted on other parameters for it to be applied on an industrial scale.