A new membrane performance index using flow-field flow fractionation (fl-FFF)

A new application of flow-field flow fractionation (fl-FFF) method was developed to quantify the interfacial interactions. The fl-FFF method was designed so as to characterize a new membrane performance index (MPI-FFF), which represents not only fouling resistibility of a membrane for a specific foulant, but also the removal capability for the foulant. Three commercial ultrafiltration (UF) and nanofiltration (NF) membranes and two foulants including organic and colloidal materials, were tested to verify MPI-FFF in lab-scale membrane fouling tests. Higher values of MPI-FFF mean better performance of membranes for a specific foulant in terms of rejection and fouling resistibility. According to the fouling tests, combinations of foulant and membrane with higher MPI-FFF values showed lower fouling and higher rejection characteristics, which means the MPI-FFF is a useful parameter to account for membrane performance. In addition, MPI-FFF values can be easily and quickly obtained for membranes and the foulants in the feed water for the selection of membrane with high performance.