Preparation and characterization of nanofiltration membranes fabricated from poly(amidesulfonamide), and their application in water-oil separation

Nanofiltration membranes prepared from selected types of poly(amidesulfonamide) (PASA) targeted to retain either sucrose, raffinose, or β-cyclodextrin were fabricated in conditions deduced from a chemometric method. Membrane performance was characterized by the permeation of solutions containing 1000 ppm carbohydrates and metal ions. To demonstrate the dependence of the membrane properties on the polymer structure, the separation characteristics of a series of four PASA homopolymers and four PASA copolymers were established. The results allowed us to screen out several promising PASA materials for the NF separation process. In addition, the superiority of the PASA materials, characterized by excellent retention and high flux rate, was evident from the results of a study comparing it with polysulfonamide, poly(ether amide), and commercially available regenerated cellulose. As a means of pollution control, the PASA NF membranes have been proven to be effective in removing oil from oily wastewater. Under an operating pressure of 2-3 psi, a constant flux of 5 L m^-2 h^-1 and 99.6% retention of a solution of 5000 ppm olive oil could be achieved with the PASA membranes over a period of 430 h.