The pseudo-second order rate model is expressed as:where *h* = *k*_{2} q_{e}^{2} which denotes the initial sorption rate (mg/g min) and *k*_{2} (g/mg min) is the rate constant of the pseudo-second order equation. The second order rate constant *k*_{2} and *q*_{e} are calculated from the intercept and slope of the plot of *t*/*q*_{t} versus *t*. The experimental data plotted is shown in Figure 8. The calculated values of *q*_{e}, *k*_{1}, *k*_{2} and *R*^{2} are presented in Table 2. The experimental *q*_{e} value is in agreement with the calculated *q*_{e} value and the plots show good linearity with an *R*^{2} value of 0.983. This indicates that the pseudo-second order kinetic model better represents the adsorption kinetics, suggesting that the adsorption process might be chemisorption. Some of the previous researchers also reported that pseudo-second order model correlates well to the experimental data obtained for the adsorption of As(III) on polymeric Al/Fe modified montmorillonite (Ramesh *et al.* 2007), fly ash agglomerates (Polowczyk *et al.* 2010) and maize leaves (Kamsonlian *et al.* 2011).

6

Table 2

. | Pseudo-first order parameters . | Pseudo-second order parameters . | |||||
---|---|---|---|---|---|---|---|

Temp (K) . | k_{1} (min^{–1})
. | R^{2}
. | h (mg/g min)
. | k_{2} (g/mg min)
. | Experimental q (mg/g)
. _{e} | Calculated q (mg/g)
. _{e} | R^{2}
. |

304 | 0.1059 | 0.976 | 0.0041 | 2.113 | 0.0392 | 0.0441 | 0.983 |

. | Pseudo-first order parameters . | Pseudo-second order parameters . | |||||
---|---|---|---|---|---|---|---|

Temp (K) . | k_{1} (min^{–1})
. | R^{2}
. | h (mg/g min)
. | k_{2} (g/mg min)
. | Experimental q (mg/g)
. _{e} | Calculated q (mg/g)
. _{e} | R^{2}
. |

304 | 0.1059 | 0.976 | 0.0041 | 2.113 | 0.0392 | 0.0441 | 0.983 |

Figure 8

This site uses cookies. By continuing to use our website, you are agreeing to our privacy policy.