Graphene oxide functionalized by ethylene diamine tetra-acetic acid (Edta) by a hydrothermal process as an adsorbent for nickel ions

Abstract

Graphene oxide (GO) from sugar cane bagasse (SCB/F) was treated with EDTA to produce modified GO (EGO) by a hydrothermal preparation reaction. Raman spectra showed an intensity ratio of ID/IG for SCB/F and EGO8:1 (EDTA:GO 8:1) of 0.598 and 0.391, respectively. FTIR spectra confirmed the introduction of nitrogen-containing groups into the SCB/F backbone. SEM analysis demonstrated the porosity character for the sample. The TGA/DTA results implied the EGO8:1 sample was less thermally stable than SCB/F. The Ni2+ adsorption study revealed a steadily increasing adsorption of Ni2+ until 45 min, with no noticeable increase in adsorption after that. The results of kinetic modeling, adsorption isotherms, and thermodynamic parameters showed that the pseudo-second-order models gave a better fit to the adsorption data of the SCB/F and EGO samples. Also, the adsorption data fitted the Langmuir model best, and the negative values of ∆G indicated that the sorption process was spontaneous.