Kinetics, equilibrium, and thermodynamics of the blue 19 dye adsorption process using residual biomass attained from rice cultivation

Novel Application of Tagua Shell (Phytelephas aequatorialis) as Adsorbent Material for the Removal of Pb(II) Ions: Kinetics, Equilibrium, and Thermodynamics of the Process

“…All experiments were performed by stirring 100 mL of Pb(II) solution at the required concentration with a dose of TSH in a 250 mL Erlenmeyer flask with stirring at a constant speed of 300 rpm. This shaking speed of 300 rpm was decided based on preliminary tests and published literature [15][16][17].…”

“…The pseudo-first order model is represented by the Lagergren equation (Equation (3)), where q e and q t are the amount of lead adsorbed at equilibrium and at time t (mg•g −1 ), respectively, and k 1 (min −1 ) is the adsorption rate constant [17].…”

“…The pseudo-second order kinetic model is also based on the adsorption capacity of the solid phase and shows the behavior of the process along the contact time phase. It is represented by Equation (4), where K 2 is the adsorption rate constant (g•mg −1 •min −1 ), and q e and q t (mg•g −1 ) are the amount of lead adsorbed at equilibrium and at time t (min) [17].…”

“…The Bangham kinetic model can be used to verify if pore diffusion is the only ratecontrolling step in the adsorption system employing this equation (Equation ( 5)), where K B (mg•g −1 •s -α ) and α B (<1) are the empirical constants of the equation, and q t (mg•g −1 ) is the amount of adsorbate retained per unit adsorbent. If the experimental data can be represented by the equation, the adsorption kinetics can be limited by diffusion in the adsorbent pores [17,18].…”

“…In Equation (7), K dif (mg•g −1 •min −0.5 ) is the Weber-Morris kinetic constant, and C is the constant related to the boundary layer. The authors have added this factor to provide an accurate representation of the possible difference in regression at the origin of the graph [17].…”