Graphene Oxide Doped CNT Membranes for Dye Adsorption

Recently, graphene oxide (GO) has been largely investigated as potential adsorbent towards dyes. However, the major obstacle to its fully employment is linked to its nat-ural powder consistence, which greatly complexifies the operations of recovery and reuse. With the aim to overcome this issue, the present work reports the design of GO modified carbon nanotubes buckypapers (BPs), in which the main component, GO, is entirely entrapped in the BP grid generated by CNTs, for the double purpose of a) in-creasing adsorption performance of GO-BPs and b) ensure a fast process of regenera-tion and reuse. Adsorption experiments were performed towards several dyes: Acid Blue 29 (AB29), Crystal Violet (CV), Eosyn Y (EY), Malachite Green (MG), and Rhoda-mine B (RB) (Ci = 50 ppm, pH=6). Results demonstrated that adsorption is strictly de-pendent on the charge occurring both on GO-BP and dye surfaces, observing great ad-sorption capacities towards MG (493.44 mg g-1), RB (467.35 mg g-1) and CV (374.53 mg g-1), due to the best coupling of dye cationic form with negative GO-BP surface. Con-firmed also by kinetic constants, where higher values are those of MG, RB and CV, the following trend in GO-BP adsorption performance has been derived: MG ≈ RB > CV > AB29 > EY.