Polymeric mixed-matrix membranes modified with halloysite nanotubes for water and wastewater treatment: A review

Polymeric membranes are widely applied for water and wastewater treatment. However, the membranes used in the pressure driven membrane processes suffer from the undesired phenomena of fouling and biofouling. That leads to a decrease in productivity and an increase in treatment costs. The membranes used in forward osmosis, being a non - pressure driven process, are less endangered by fouling; nonetheless, due to low permeation they have limited potential in wastewater treatment. To improve the membranes performance with reference to permeability, antifouling/antibiofouling resistance and separation properties the application of various nano-materials has been proposed. This review presents a progress in the research on the polymer mixed-matrix membranes containing pure and modified halloysite nanotubes (HNTs). The effect of HNTs on the properties and performance of membranes made of polymers such as polysulfone, polyethersulfone, polystyrene and polyvinylidene fluoride is widely discussed. Finally, the key issues to be considered in further research on the mixedmatrix membranes modified with HNTs are proposed.

Automated summary

Polymeric membranes are commonly used in water and wastewater treatment, but pressure-driven membranes are prone to fouling and biofouling. On the other hand, forward osmosis membranes are less affected by fouling but have limited potential in wastewater treatment due to low permeation. The use of various nano-materials has been proposed to enhance membrane performance in terms of permeability, antifouling/antibiofouling resistance, and separation properties.