The proposed mechanism causing the isotherm shift originated in our recent paper, where we reported strong and long-range repulsion between oppositely charged surfaces. We showed that localized excess ions caused the influx of water molecules, increasing osmotic pressure. This manifested as a measurable force acting at long distances (much larger than Debay length). PSiFe particles at the KCl subphase constituted a similar system, where the excess of ions was due to the chaotropic effect. These ions were localized at the air/water interface, causing an imbalance in the distribution of ions. This osmotic pressure separated PSiFe to dilute the ions at the interface effectively. Such reasoning aligned with thermodynamics, where chemical potentials close to the interface significantly differed from the bulk. As a result, fluxes acted against such imbalance to minimize the differences.