## Pseudo second order equation equation

3.3. Adsorption kinetics

Adsorption rate Umeclidinium bromide very significant for practical applications. The pseudo-first-order and pseudo-second-order models are herein used to describe the adsorption kinetics.

Pseudo-first-order equation:equation(1)Qt=Qe(1-exp(-k1t))Qt=Qe(1-exp(-k1t))

Fig. 3. Time-dependent Pb(II) (a) and Cd(II) (b) sorption on PS-GO gel, pH = 5.0 for Pb(II) and 6.0 for Cd(II), T = 303 K, C0 = 20 mg/L or 40 mg/L, and m/V = 1 g/L.Figure optionsDownload full-size imageDownload as PowerPoint slide

Table 2.

Constants for the kinetic sorption data using different sorption models.MetalsQe,exp (mg/g)Pseudo-first-orderPseudo-second-orderk1 (L/min)Qe,cal (mg/g)R2k2 (g/(mg·min))Qe,cal (mg/g)R2Pb39.60.069739.30.99190.001845.570.9625Cd41.50.038838.60.99270.000848.130.9896Full-size tableTable optionsView in workspaceDownload as CSV

3.4. Adsorption isotherms

In order to gain a better understanding of sorption mechanisms and evaluate the sorption performance, the experimental data for metal ions adsorption onto PS-GO gel are isotonic analyzed using the Langmuir, Freundlich and Dubinin–Redushckevich adsorption isotherm models.