The porous carbon/Ni nanoparticle composite was prepared by a freeze-drying method using NaCl as the template. It was applied in the effect of the concentration, adsorption time, and temperature of adsorption on the adsorption behavior. The kinetic model and the adsorption isothermic fitting results show that the adsorption behavior fits with the pseudo-secondary dynamics and the Langmuir isothermal model, indicating that the adsorption process is monolayer adsorption. Thermodynamic results indicate that the adsorption process is spontaneous physicochemical adsorption. The fitting showed that the porous carbon/Ni nanoparticle composites reach 217.17 mg·g^-1, at 313 K indicates good adsorption for Congo red.

Adsorption is a widely used method for the treatment of dissolved contaminants. Various agro-industrial wastes have been explored as potential adsorbents, showing high efficiency in dye removal. Each adsorbate-adsorbent pair needs kinetic, and equilibrium models to scale up this process. In this work, the equilibrium, kinetics and thermodynamics of the corn Tuza-Red 40 system were evaluated under batch system at ph = 2.0 at temperatures of 25, 40, and 55 °C. The Langmuir, Freundlich and Temkin models were selected for the isotherm representation, while the Lagergren, Ho, and Elovich equations for the kinetics of the process. The Freundlich model presented the best fit to the isotherms, the adsorption kinetics was best described by the Ho equation, and the values for Gibbs free energy and entropy indicated the spontaneity and feasibility of the process.