Superior adsorption performance of citrate modified graphene oxide as nano material for removal organic and inorganic pollutants from aqueous solution

Abstract

This work addressed one step preparation method to form a novel nano material composite of graphene oxide nanosheet (GO) functionalized with low-cost tri-sodium citrate (C), using, teteraethylorthosilicate (TEOS) as a cross-linker. The prepared composite (GO–C) was characterized using various advanced techniques. Among these techniques, the TGA provided interesting information concerning the functionalization process. Within this process, the (–OH) groups that located at the GO-surface were consumed in the modification process which leads to increase the thermal stability of the resulted composite. Cationic organic methylene blue (MB) and crystal violet (CV), and inorganic copper (Cu²⁺) and cobalt (Co²⁺) pollutants were displayed as a model to assess their removal performance by the developed composite (GO–C) from aqueous solution, through batch technique. According to Langmuir isotherm the GO–C present an excellent adsorption capacity for MB (222.22 mg g⁻¹), CV (270.27 mg g⁻¹), Cu²⁺ (163.4 mg g⁻¹) and Co²⁺ (145.35 mg g⁻¹) which were more than the adsorption capacities found in literature. Additionally, the regenerated composite presents higher removal ability than the original composite.