Fabrication and characterization of polyethersulfone nanocomposite membranes for the removal of endocrine disrupting micropollutants from wastewater. Mechanisms and performance

Abstract

The addition of carbon nanotubes to improves the removal and adsorption of endocrine disrupting micropollutants (bisphenol A and nonylphenol). Increasing the SWCNT (single walled carbon nanotubes) content increases removal and diminishes reversible and irreversible fouling. The isoelectric point of the SWCNT containing membranes decreases when the content of nanotubes increases with more negative charges at alkaline pH. Because, the nanotube loaded membranes are also less hydrophilic and bisphenol and nonylphenol are hydrophobous, adsorption plays a key role in the removal of micropollutants. An increase in the transmembrane applied pressure decreases the removal and more steeply for the membranes containing more SWCNT. Higher porosities, leading to higher water permeabilities, are also obtained for more loaded membranes. Too high SWCNT contents lead to a saturation and decrease of removal probably because high porosities lead to a decrease in adsorption due to both a decrease in the available surface and a sweeping action of convection through the membrane.