Seawater pretreatment with microfiltration and ultrafiltration is technically and economically feasible, with advantages over conventional granular media filtration. However, current membranes have short lifespans and wear irreversibly over time, especially in the presence of abrasive particles in seawater.
Australian researchers have reported the fabrication of novel polyvinylidene fluoride (PVDF)/nanoclay hollow fibre membranes using non-solvent induced phase separation (NIPS), to study improved membrane physical endurance.
Loss on ignition testing has shown that high nanoclay retention was achieved at low initial nanoclay loading. Despite showing lower pure water permeability, the incorporation of nanoclay shifted the PVDF crystalline phase from α-phase to β-phase. It also improved the membrane structure, as well as mechanical properties in terms of stiffness and flexibility.
The tensile strength increased from 3.8 MPa to 4.3 MPa with 5.08 wt% Cloisite® 30B loading, while break extension increased from 175% to 229% with 5.08 wt% Nanomer® I.44P nanoclay loading.
An accelerated abrasion test revealed that the membrane with an initial 5.08% loading of Nanomer I.44P had improved abrasion resistance, lasting three times longer than the control membrane with no nanoclay addition.
Thus PVDF membranes containing commercial nanoparticles look promising for improved abrasion resistance in water treatment applications.