Adsorption of nitrate and phosphate ions from aqueous solutions using organically-functionalized silica materials: Kinetic modeling

► C3H6-NH3+-mesoporous silicas were high capacity adsorbents for nitrate and phosphate. ► A kinetic study was conducted for the first time for such adsorbents and adsorbates. ► The adsorption was very fast reaching equilibrium within 5 min of contact time. ► Pseudo-second-order model described adequately the experimental kinetic data. ► The activation energy was 6.91 kJ/mol for nitrate and 8.59 kJ/mol for phosphate.