Effect of the mass ratio of dopamine to salicylaldoxime on the adsorption performance of polydopamine/salicylaldoxime functionalized magnetic graphene oxide

Abstract The effective combination of dopamine (DA) and oxime-containing molecules can significantly improve adsorption performance. To characterize the role of the mass ratio of DA to oxime-containing molecules, novel polydopamine/salicylaldoxime-functionalized magnetic graphene oxides (MGO-PDA/oxime) with different mass ratios of DA to salicylaldoxime (i.e., 1:0.5, 1:1, 1:2, and 1:4) were synthesized successfully via rapid one-step polymerization. The mass ratios of DA to salicylaldoxime influence the thickness of the polymer shell, functional groups, crystallinity, surface charge, and consequently adsorption capacity of composites. According to the results of batch experiments, MGO-PDA/oxime with a DA/salicylaldoxime ratio of 1:2 (i.e., MGO-PDA/oxime-2) shows the best performance for Pb(II) removal, with a maximum adsorption capacity of 261.55 ​mg ​g−1. The adsorption of Pb(II) on MGO-PDA/oxime-2 is fast, and pH- and temperature-dependent. The remarkable Pb(II) adsorption efficiency, easy separation and good reusability imply that MGO-PDA/oxime-2 can be regarded as a suitable material for heavy metal pollution cleanup.