Modeling and optimization of ultrasound-assisted adsorption of crystal violet dye by graphene oxide nanoparticles using response surface methodology

In this research, the ability of synthesized graphene oxide nanoparticles (GONPs) for the removal of crystal violet (CV) dye from the aqueous solutions is described. The structure of the GONPs was characterised with FTIR, SEM, TEM and XRD techniques. The interaction and significance of parameters such as the amount of adsorbent, pH, ultrasound time and initial concentration of CV dye on the removal efficiency of the dye were studied by Central Composite Design (CCD) coupled with Response Surface Methodology (RSM). The utmost adsorption was obtained at the variables set of 0.6 g/L GO, pH of 8, 30 min of sonication and 80 mg/L of dye concentration at room temperature. The efficiency of adsorption was obtained more than 90% under the optimized parameters of the process. The results specify that the R(2)value was 0.802, while the adjusted R(2)was 0.629. The equilibrium data fitted better to the Langmuir model than the Freundlich model, while the Langmuir monolayer adsorption capacity was 166 mg g(-1)for CV dye. The kinetic studies confirmed that the pseudo-second-order model was best fitted for the adsorption process of the dye.