Optimising the basic violet 16 adsorption from aqueous solutions by magnetic graphene oxide using the response surface model based on the Box–Behnken design

Abstract

ABSTRACT The coloured wastewater from the textile industries may show toxic or carcinogenic effects on the organism, when discharged into the rivers and lakes, which are changing their biological life. Therefore, in this study, the removal of basic violet 16 was investigated by a magnetite graphene oxide nanocomposites (Fe3O4@GO) optimising by the response surface methodology based on Box–Behnken method. Fe3O4@GO nanocomposite was prepared by a facile in situ co-precipitation method, resulting in a suitable composite for the adsorption of dye. The structure and morphology of the Fe3O4@GO adsorbent were investigated using XRD, FT-IR, SEM, BET and VSM techniques. Base on the SEM images, the Fe3O4 NPs were distributed between the GO sheets and empty spaces with visible large pores between GO sheets. Also, the results of the FT-IR analysis showed that the dominant group was carboxyl group. The various parameters were evaluated in the process such as pH, reaction time, adsorbent dose and initial concentration of dye. The proposed model (quadratic) was approved with a high correlation coefficient (R2 = 0.98) and (R2 adj = 0.97). Desirable removal of dye (efficiency: 95.03%.) was obtained under following conditions: the dye concentration of 62.5 mg L−1, the absorbance of 0.2 g L−1, the reaction time of 60 min and solution pH of 7.5. The results of isotherms and kinetics adsorption study showed that the adsorption process follows the Langmuir isotherm (R2: 0.98) and the pseudo-second-order kinetic (R2: 0.99) models. The present study showed that the Fe3O4 @GO adsorbent has a high efficiency in the removal of violet 16.