Fouling behavior and micropollutants removal during treatment of surface water by ultrafiltration using nanocomposite membranes

Abstract

Fouling is an accumulation of pollutants from feed water on the membrane surface, a phenomenon in which feed impurities form a layer on the surface of the membrane. They are usually high molecular weight impurities forming so-called filter cake. The formation of such cake on one hand causes a deterioration of flow through the membranes, but on the other hand it can create an additional layer in which microcontaminants can be removed. This study presents fouling behavior of nanocomposite membrane during ultrafiltration treating water spiked with organic micropollutants with different properties (caffeine, bisphenol A, carbamazepine, and β-endosulfan). The river water was used as feed water to reflect ultrafiltration conditions in commercial scale. Ultrafiltration was conducted under constant transmembrane pressure and temperature in the cross-flow filtration system. Membranes were modified by single-walled carbon nanotubes functionalized with carboxyl groups. Obtained results showed, that the most antifouling membrane was that with the highest concentration of nanotubes, however, it was a membrane with the lowest retention level and highest flux. The most effective was the membrane with an intermediate amount of nanotubes in its structure.