Kinetics and thermodynamics for Cu2+ adsorption by modified corn straw
改性玉米秸秆吸附Cu2+的动力学和热力学

A sort of modified corn straw by using ZnCl2 as activating agent was used as adsorbent for removal of Cu2+ from aqueous solution. The influences of dosage, pH, adsorption time, initial concentration and reaction temperature were investigated on adsorption properties through dynamic tests. Adsorption isotherm models, thermodynamics models and kinetics models of the adsorption process between modified corn straw and Cu2+ were systematically studied. The results showed that the modified corn straw had maximum adsorption efficiencies when the dosage was 0.2 g, the pH was 6. The adsorption reached equilibrium after 8 hours. The adsorption process can be fitted very well by Langmuir and Freundlich adsorption isotherms and the quasi-second order kinetics equation. Gibbs free energy was less than zero, which showed that the reaction process was spontaneous.