Application of Optimization Response Surface for the Adsorption of Methylene Blue Dye onto Zinc-coated Activated...

The activated carbon was produced in the first phase of this investigation by chemically activating hazelnut shell waste with H₃PO₄. Composite materials were obtained by coating the activated carbon with zinc oxide, whose BET surface area was calculated as 1278 m² g^-1. ZnO-doped ZnO/AC composite was synthesized as an adsorbent for its possible application in the elimination of organic dyestuff MB, and its removal efficiency was investigated. Morphological properties of ZnO/AC were characterized using analytical methods such as XRD, SEM, and BET. The adsorption system and its parameters were investigated and modeled using the response surface method of batch adsorption experiments. The experimental design consisted of three levels of pH (3, 6.5, and 10), initial MB concentration (50, 100, and 150 mg L^-1), dosage (0.1, 0.3, and 0.5 g 100 mL^-1), and contact time (5, 50, and 95 min). The results from the RSM suggested that the MB removal efficiency was 98.7% under the optimum conditions of the experimental factors. The R² value, which expresses the significance of the model, was determined as 99.05%. Adsorption studies showed that the equilibrium data fit well with the Langmuir isotherm model compared to Freundlich. The maximum adsorption capacity was calculated as 270.70 mg g^-1.