Preparation of Polyelectrolyte Modified Membrane for Removal of Arsenic

Abstract

Polyvinylidine fluoride was modified using polyelectrolyte (PE) multilayers, made of poly (allylamine hydrochloride) with poly (styrene sulfonate) to remove arsenic cations from aqueous solution. From the characterization of the naked and modified membrane using IR-ATR and water contact angle, it is shown that the polycation and polyanion has successfully been deposited on the surface of the membrane. The contact angle increased with the increasing layers of polycation while it decreased with increasing polyanion layers. Hence, the modification of the membrane was successful. It also has been shown that filtration through modified membrane is a process that can effectively remove metal ions from contaminated aqueous solutions. The efficiency of the filtration process as measured by the rejection rates of the modified membrane is around 20% to 60% for both 1 ppm and 10 ppm metal ions solutions and is greater than the naked membrane. As expected, the cross-flow velocity decreased as the number of deposited polyelectrolyte layers increases. The mechanism for the arsenic removal is electrostatic repulsion. Consequently, the use of layer by layer-modified membranes is a viable option for the removal of arsenic from wastewater.