Soon Il Higashino ’20


Civil and Environmental Engineering

Project Title

Investigating the Effects of Cations and Salinity on Adsorption of Perfluorobutanesulfonic Acid onto Montmorillonite Clay

Presentation Link

View Soon Il 's Presentation

Per- and polyfluoroalkyl substances (PFAS) are man-made compounds capable of persisting in the environment long after introduction. Adsorption onto minerals, such as montmorillonite clay, may potentially serve as an effective way to remove PFAS from water. I examined how cations and salinity influence the adsorption of perfluorobutanesulfonic acid onto montmorillonite clay. Three batch adsorption experiments tested NaCl solutions of .01 M and 1M, and a KCl solution of .1 M, at five concentrations (80 μL, 60μL, 40 μL, 20 μL, 10 μL), including blanks and standards, to determine the adsorption coefficient Kd. The Na-montmorillonite with .01 M salinity yielded a Kd value of 270 ± 73 L solution/kg (log Kd = 2.43 ± 1.86); Na-montmorillonite with 1 M salinity gave a Kd value of 156 ± 40 L solution/kg (log Kd = 2.19 ± 1.60); and K-montmorillonite with .1 M salinity gave a Kd value of 1016 ± 55 L solution/kg (log Kd = 3.01 ± 1.73). This suggests that increasing salinity leads to a decrease in adsorption of PFBS onto Na-saturated smectite, and of the cations Na, Ca, and K, the presence of K led to an increase in adsorption.

Internship Year


Project Category

Climate Change and Environmental Science


Interfacial Water Group, Department of Civil and Environmental Engineering, Princeton University- Princeton, New Jersey


Ian Bourg, Assistant Professor of Civil and Environmental Engineering and the Princeton Environmental Institute