Fast and efficient separation of seawater algae using a low-fouling micro/nano-composite membrane

High suspended solid loadings due to harmful algal bloom (HAB) pose serious threat to the operation of membrane based desalination plants. Clogging of algal biomass could lead to irreversible damage of the filtration units and eventually disrupting the sustainability of water supply. In this study, we demonstrated a fast and efficient method for separating algae from seawater using a low-fouling micro/nano-composite membrane. The composite membrane was made of a nanoporous nanofiber selective layer on top of a microporous microfiber support layer. The optimized nanoporous selective layer of this composite membrane can effectively separate seawater algae with high efficiency (average 99%) and high flux (3 × 10−5 m3/m2·s) under low operation pressure. More importantly, the membrane exhibits excellent anti-fouling property by maintaining constant water flux and algae rejection rate after a simple backwashing without chemical usage. This superior antifouling property attributes to the underwater superoleophobicity of the composite membrane. These combined merits of fastness, effectiveness and fouling resistance render this membrane-based separation method with greater potential for industrial application.