Investigation of Kinetic and Isotherm Models for the Removal of Nitrate and Nitrite Ions on MNPs@PIL Adsorbent from Aqueous Solution

Abstract

In the previous work synthesis and characterization of magnetic nanoparticles modified with poly ionic liquid and its application in magnetic solid phase extraction of nitrate and nitrite was reported. In the present work, the kinetics of adsorption of nitrate and nitrite on the synthesized adsorbent was investigated by four kinetics models including pseudo first order, pseudo second order, Elovich and Intra particle diffusion models. The rate constants of all these models were calculated. The results showed that, the pseudo second order and the pseudo first order models were suitable to describe the adsorption kinetics of nitrate and nitrite, respectively. Also four isotherm models including Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models were applied to find the best model which fitting the experimental data. The results showed that adsorption of both anions followed Langmuir isotherm model. Equilibrium parameters such as maximum adsorption capacity, adsorption constant and equilibrium concentration were calculated.