Synthesis and characterization of graphene oxide/alginate and application of central composite design in the adsorption of Th(IV) on the nanobiocomposites

In this study, graphene oxide and aginate were used to synthesis of nanobiocomposites under different synthesis conditions and the used to investigate the adsorption properties of Th (IV) ions from aqueous solutions. BET surface area, SEM and TEM images, FT-IR spectrometry, XRD techniques were used for the characterization of the adsorbents. In batch adsorption experiments, parameters affecting the adsorption efficiency such as solution pH, contact time, Th (IV) concentration and temperature were investigated using central composite design (CCD). ANOVA (analysis) analysis at the 95% confidence interval of the model applied for the experimental design and the compatibility of this model with the experimental findings were examined. The relevance of the model for the nanobiocomposite prepared by the 1st method is that the P value is F value is 23.77 and 39.45 with the 2nd method, respectively. These results show that the regression for this method is statistically high. The correlation coefficient (R 2), which was 95.69% for the 1st method and 97.36% for the 2nd method, indicates a high coordination between the observed values and the estimated values. According to the CCD results, it has been observed that the main effects of the adsorption process with the materials obtained by the 1st method are in the direction of increasing the concentration, while pH, time and temperature do not have a statistically significant effect. In the adsorption process with the materials obtained by the 2nd method, it was observed that the concentration, time and temperature caused an increasing effect. Langmuir, Freundlich and Dubinin–Radushkevich isotherms were used to determine the adsorption model and the constants related to these isotherms were calculated. In addition, the adsorption process was also investigated in terms of thermodynamics.