Cluster adsorption of L-histidine on carbon nanotubes at different temperatures

The adsorption isotherms of L-histidine on MKN-SWCNT-S1 CNTs from aqueous solution at temperatures of 25, 35, 45, 55, 65 and 80 °C were interpreted within the framework of the single-layer cluster adsorption model. A new approach to determine the equilibrium parameters of the cluster adsorption isotherm equation and sorbate structure on CNTs, as well as a nonlinear modelling method, was applied. To confirm the cluster nature of amino acid adsorption on CNTs, the clustering criterion proposed in the previous work was applied, and the cluster structure was evaluated, which is significant for the application of CNTs in biomedicine. The found equilibrium parameters of adsorption were applied to the determination of thermodynamic characteristics of adsorption (changes in Gibbs energy, enthalpy and entropy) of L-histidine on CNTs and the character of adsorption was analysed. [Display omitted] •The adsorption isotherms of L-histidine on CNTs were interpreted within the framework of the cluster adsorption model.•The cluster character of L-histidine adsorption on CNTs was proved.•The parameters of adsorption isotherms and the structure of histidine clusters on CNTs were determined.•The linearisation method was applied to determine the parameters of adsorption isotherms.•The found isotherms parameters were applied to the determination of thermodynamic characteristics of adsorption.