Abstract
Extrinsic compensation, the adsorption of counter ions to the excessive charges in layer-by-layer (LBL) nanofiltration (NF) membrane, has been proposed as an important factor in determining the NF separation performance. This paper reported the evidence of extrinsic compensation of positively overcompensated poly(styrene sulfonate) (PSS)/poly(allylamine hydrochloride) (PAH) LBL NF membranes by phosphoric anions. Direct observation of phosphorous (P) element by X-ray photoelectron spectroscopy in LBL membrane after being soaked in H3PO4 was accompanied by reduced zeta potential from positive to negative (pH = 7) and the consequently improved rejection to Na2SO4 with no discernable alteration in pore size. Similar changes of LBL membrane performance were observed after soaking in other strong acids including H2SO4, HNO3 and HCl. This result opens a new concept for understanding the ion-membrane interaction in determining the separation performance of nanofiltration. Systematic elaboration of this factor in LBL membrane design is needed in future study.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
