Adsorption of p-Cresol on Al₂O₃ coated multi-walled carbon nanotubes: Response surface methodology and isotherm study

The development and design of adsorbents with high adsorption performance is an effective method of removing p-Cresol from effluent for environmental protection. Therefore, an Al₂O₃ coated multiwalled carbon nanotubes (MWNTs) composite for adsorption of p-Cresol from aqueous solution was synthesized. The p-Cresol concentration was determined by estimating the absorbance of the sample solution on a DR5000 UV/vis spectrophotometer. Box–Behanken design (BBD) was involved in the optimization of p-Cresol adsorption upon Al₂O₃ coated MWNTs adsorbent against the process parameters time, pH and adsorbent dose. The effects of these factors were studied in the ranges 5–40 min, 4–10, and 0.2–2 g L⁻¹, respectively. The lack of fit obtained for this model was 0.357 which confirmed that the model is highly significant and the experiments are accurate and reliable. The results showed that adsorption isotherms fit well with the pseudo-second-order kinetic model and Langmuir isotherm model and Q_max was calculated to be 54.05 mg/g. Our results demonstrate that Al₂O₃ coated MWNTs has the potential to be used as an effective adsorbent for the rapid uptake of p-Cresol from aqueous solutions.