Nanofiltration processes applied to the removal of phenyl-ureas in natural waters

Facile filtration system to remove Diuron in aqueous solutions

Exposure to the herbicide Diuron may cause many undesirable effects on human health, leading to an increasing concern to preserve the quality of water intended for consumption. Therefore, the present study evaluated the removal of this contaminant in a gravitational filtration system, using different types of activated carbon fiber felt (ACFF) supported on the microfiltration membrane. The properties of the ACFF samples were investigated by X-Ray diffraction (XRD), Raman spectroscopy, Nitrogen adsorption assays, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and zeta potential analysis. The characterizations suggested that ACFF could be appropriate to remove Diuron in aqueous solutions. Among samples, the one denominated as ACFF-CO₂(200)H₂O showed the best performance during the permeation tests. In the first filtration cycle, the system took about 530 min to reach the saturation point (removal ceased), and 190 min for the second cycle. Along the process, the contaminant solution fluxes were higher than 100 L h^{- 1} m² and reached an average final removal of ~ 50%. These results were excellent, as the proposed treatment consists of a simple gravitational filtration system, easy to operate, and low-cost.