A similar explanation has been proposed by Han et al. [43] and Senthilkumaar et al. [47]. Similar conclusions on the effect of contact time on adsorption of dyes have been proposed by other workers. Khattri and Singh [48] tested the adsorption of malachite green by neem sawdust, Chowdhury et al. [42] used chemically modified rice husk for the adsorption of malachite green and Hameed and Ahmad [5] analyzed the adsorptive removal of methylene blue from aqueous solution by garlic peel.