Synthesis of a novel graphene-kaolin-alginate adsorbent for dye removal, and optimization of the adsorption by response surface methodology

摘要

In this study, a novel sodium alginate, kaolin, and graphene nanoplate based bio-adsorbent was synthesized and used for cationic dye removal from synthetic wastewater. Central composite design of response surface methodology was applied for the optimization of dye adsorption onto the bio-adsorbent. Effects of dye concentration (from 2.5 to 7.5ppm), pH (from 5 to 9), and adsorption dosage (from 5 to 15g/L) were investigated to determine the optimum design points. According to the experimental design, the lowest dye removal was found as 64.80% when the adsorbent dosage was 5g/L, dye concentration was 7.5ppm and the pH value was 5. According to the design response, 63.16% of dye removal was achieved at the same conditions. The highest dye removal of 95.42% was obtained when the pH was 5, dye concentration was 2.5ppm and the adsorbent dosage was 15g/L. The experimental study gave the removal result of 94.94% at the same operating conditions. The model fitted with the experimental values with R-2=0.97. The regeneration efficiency and reusability of graphene-kaolin-alginate beads were investigated by using desorption experiment. Adsorbents showed a removal efficiency of 97% after the regeneration.