Response surface methodology optimization of integrated fluidized bed adsorption–Fenton oxidation for removal of Reactive Black 5

Abstract

Fenton oxidation was integrated with fluidized bed activated carbon to remove a recalcitrant pollutant, Reactive Black 5. Palm kernel shell was used as a low-cost adsorbent, which was characterized using Fourier transform infrared, scanning electron microscope, and energy-dispersive X-ray spectroscopy analyses. Response surface methodology using Box–Behnken Design was employed to study the effect of operational parameters ([Fe²⁺], [H₂O₂], pH, and adsorbent dosage) on the process performance. The optimum conditions for the combined process were pH = 3.53, [Fe²⁺] = 2.92 mM, [H₂O₂] = 104.8 mM and 29.86 g/L adsorbent dosage. Under these conditions, the COD and color removals were 61.01% and 99.78%, respectively. The presence of activated carbon enhances the dye removal, though the Fenton oxidation was still the dominant process due to the rapid oxidation by hydroxyl radicals. The removal of the dye was effective in the pH range of 3–7, indicating the potential of applying the integrated process under a wide range of pH. There was a good agreement between the experimental results and those predicted by the response surface models, indicating the applicability of the proposed models. This study has shown that integrated fluidized bed adsorption–Fenton oxidation is a viable treatment option for dye-containing wastewater.

Keywords:

• Activated carbon
• adsorption
• Fenton oxidation
• fluidized-bed
• response surface methodology

Additional information

Funding

The authors acknowledge the financial support from the University of Malaya through a Postgraduate Research Grant (PPP) Number PG086-2016A.