Nanofiltration (NF) lies between reverse osmosis (RO) and ultrafiltration (UF). Nanofiltration membrane carries quite distinctive properties such as pore radius and surface charge density which influences the separation of various solutes. This paper reviews the recent patents available in nanofiltration. In oil processing industry, nanofiltration has been used in recovery of crude oil, where sulfate reduced feed water was introduced. It also leads to the production of useful chemicals. In desalination applications, the nanofiltration has been used as a pretreatment process for reverse osmosis and thermal desalination systems, in former, it removes the biofouling potential components and multivalent ions, which results in increase in product recovery of RO process and in later, it allows to increase the top brine temperature of Multi Effect Distillation (MED) and Multi Stage Flash (MSF), which results in increase in production water and lesser scaling propensity. There is also growing trend that utilization of dual nanofiltration in sea water applications results in reduction in energy and water cost. Utilization of solvent resistant nanofiltration for processing organic solvents under different conditions in petrochemical industries is also discussed. The review also carries the recent patents available in waste water treatment process and food industries.
Nanofiltration, desalination, oil processing, wastewater treatment, food industries
Doosan Desalination R Centre, Doosan Heavy Industries and Construction, Dubai, United Arab Emirates.