Author Experimental method n Bohm et al. Mass transfer 0.250 Noseir et al. Mass transfer 0.242 Sharma et al. Mass transfer 0.290 Fair et al. Mass transfer 0.220 Zewail Ion exchange of Ni+2 0.58 Zewail Ion exchange of Cd+2 0.25

Table 4: Effect of the superficial gas velocity on the mass transfer ( KαVgn).