Study functionalized graphene oxide performance for strontium adsorption from aqueous solutions using response surface methodology

In this study, graphene oxide (GO) adsorbent was prepared by modified Hummer’s method and functionalized with aminomethylphosphonic acid. Its application to the adsorption of Sr ions from aqueous solutions in a batch sorption process was investigated. Adsorbents were characterized by TEM and FT-IR. The TEM images of functionalized graphene oxide showed that graphene sheets are formed in wavy sheets. The FTIR spectrum revealed that graphene oxide was highly functionalized with aminomethylphosphonic acid and oxygenated functional groups were reduced. Response surface methodology investigates pH, adsorbent dosage, and temperature parameters. The quadratic model corresponds well with the experimental data. The results illustrated that there is no systematic error in the experiments. The verification of the model with random experiments showed a low error in the values predicted by the model. The kinetic data were analyzed by Pseudo-first-order, Pseudo-second-order, and Double- exponential kinetic models, and experimental data were well modeled by the pseudo-second-order kinetic model. The research results showed that graphene oxide functionalized with aminomethylphosphonic acid has a good ability to strontium adsorption from aqueous solutions.