A free-standing calcium alginate (CA) hydrogel filtration membrane was prepared using polyethylene glycol (PEG) as the pore-forming agent.The surface morphology of the filtration membrane was studied through SEM and digital photos.The relationships between flux and compression ratio

mechanical behavior of the filtration membranes were studied.The effects of the concentrations of sodium alginate (SA) and polyethylene glycol on the pure water flux (PWF) and filtration properties of lysozyme (Lyz) solutions were investigated.Results showed that CA filtration membrane prepared using a low SA concentration and a high PEG concentration had a high flux and compression rate.The PWF increased with increase in the pressure initially

and then reached a stable value.The fluxes of Lyz and bovine serum albumin (BSA) solutions were 89.97% and 94.6% of the PWF

respectively

indicating that the CA filtration membrane exhibited good anti-fouling properties.The filtration performance of the membranes was also evaluated using an oil-water emulsion and the flux was 93.04% of the PWF with a rejection rate of 99.85%.The rejection of CA filtration membranes prepared with PEG of different molecular weight was characterized by rejecting solutions of PEG with different molecular weight.The results showed that the rejection of PEG with the molecular weight bigger than that of the pore-forming agent reached above 90%.Dyes rejection studies conducted that the free-standing membrane prepared with low molecular weight of PEG can achieve the rejection rate of brilliant blue G250 as high as 99.75% and can be used as a nano-filtration membrane.