(510u) Use of Surface-Modified Nanocomposite for Advanced Pvdf Membrane

The effect of three different nano-particles on the physical properties and performance of PVDF membrane was investigated. The PVDF membranes were prepared by phase inversion method using DMAc and water as the solvent and non-solvent systems, respectively. Pure PDVF membranes were prepared and tested as the control. Three different types of nano-particles were prepared as fillers: [1] silver [2] Silica and [3] Silica-silver nanocomposites. These fillers are expected to either enhance or reduce the weak properties of the PDVF membranes. Specifically, silica for example is expected to increase the hydrophilicity of the PVDF membrane due to its hydrophobic property. Upon doing so, water permeability is expected to increase. The presence of hydrophilic properties may also reduce the membrane affinity to hydrophobic foulants hence; fouling problems is expected to be reduced due to silica fillers. Silver is a known anti-microbial element, its addition to the membrane as filler is speculated to aid in removal and decontamination of water from most of the waterborne pathogenic bacteria. Combination of these two nano-particles as Silica-silver nanocomposites may give a more enhanced physical properties of the membrane. Silver nano-particles were prepared by aqueous reduction of silver perchlorate in sodium borohydride solution in the presence of sodium citrate. Silica nano-particles were synthesized using the modified Stöber method and the silica-silver nanocomposites were prepared using a combination of the methods used for separated preparation of Ag and silica with the addition of polymer anchor as polyvinylpyrrolidone. All the nano-particles were characterized using transmission electron microscopy and UV-visible spectroscopy. Different weight ratio of each type of nanoparticles was dispersed into the PVDF solution, separately in order to obtain their effects on the membrane characteristics. For the testing of the membranes, water flux was obtained using a water permeation cell. The morphologies of each membrane type was observed using scanning electron microscopy and the pore size was obtained using the Cantor's relation and Hagen-Poisuelle's equation. The % porosity was quantified on the basis of the membrane weight following an equation previously described in the literature. The mechanical properties were tested using the universal testing machine. The hydrophilicity was tested by measuring the contact angle of the membrane. For the anti-fouling tests, a model compound of bovine serum albumin was used as the foulant. Water permeabilities were recorded as well as the flux declines. For rejection experiments, poly styrene was used as the model compound. For the anti-microbial enhancement of the membrane, E. coli suspended in buffer solution was used as the testing organism.