Adsorption kinetics, isotherms and thermodynamics of atrazine on surface oxidized multiwalled carbon nanotubes

The adsorption kinetics, isotherms and thermodynamic of atrazine on multiwalled carbon nanotubes (MWCNTs) containing 0.85%, 2.16%, and 7.07% oxygen was studied. Kinetic analyses were performed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The regression results showed that the pseudo-second-order law fit the adsorption kinetics. The calculated thermodynamic parameters indicated that adsorption of atrazine on MWCNTs was spontaneous and exothermic. Standard free energy (ΔG0) became less negative when the oxygen content of MWCNTs increased from 0.85% to 7.07% which is consistent with the low adsorption affinity of MWCNTs for atrazine.