Competitive water adsorption for low-energy desalination: Insights from statistical physics theory

In this research, the statistical physics theory has been deployed to unlock the mysteries of water molecule binding on Zeolite and Silica Gel at the microscopic level. The adopted computational procedure, based on the grand canonical partition function, provided physical insights of the docking mechanism by scrutinizing the stereographic and energetic variables. The number of receiving sites, their densities, the saturation amount and the energetic factors were assessed due to the strong consistency between the numerical and experimental results. Docking inspections revealed that H2O primarily adopted a non-parallel orientation upon interaction with the adsorbent receptor sites. The estimated attachment energies ranged from 18.25 kJ/mol to 24.55 kJ/mol indicating a physisorption process where weak forces (van der Waals) mainly govern the surface occupancy. Desalination effectiveness has been examined and according to calculations the coefficient of performance (COP) and the quantitative efficiency metric (QEM) is 2.7 times and 1.2 times respectively greater in case of Zeolite than Silica Gel. By analyzing pore size distribution (PSD) and adhesion energy distribution (AED), this study elucidates the relationship between pore size and target molecule capture, and predicts binding strength and potential for molecule capture/release under various conditions.