Optimization of Dry Desulfurization Using Regenerated Spent AZ‐300 Adsorbent Through Box–Behnken Design Approach

ABSTRACT This study explores the reuse of a commercial composite alumina‐zeolite adsorbent, AZ‐300, which has been previously employed to remove typical industrial process wastes, such as moisture and CO 2 , for SO 2 adsorption from gas streams. The spent AZ‐300 was regenerated through heat treatment and an N 2 flow and characterized using Fourier transform infrared spectroscopy (FTIR), Bruneau–Emmet–Teller (BET) specific surface area and pore analyzer, and scanning electron microscopy (SEM). SO 2 adsorption was optimized using response surface methodology (RSM) with Box–Behnken Design (BBD), considering three operational parameters: temperature (40°C–80°C), inlet SO 2 concentration (1000–2000 ppm), and adsorbent dosage (0.2–1 g). The optimal conditions for SO 2 adsorption were determined to be 40°C, 1500 ppm SO 2 , and 1 g of regenerated AZ‐300. The experimental results exhibited a strong correlation with model predictions ( R 2 = 0.9979), confirming the reliability of the optimization approach. The highest adsorption capacity reached 42.94 mg/g, and kinetic analysis indicated that the SO 2 adsorption of both spent and regenerated AZ‐300 followed the pseudo‐first‐order model, suggesting physisorption as the predominant mechanism. Both film diffusion and intraparticle diffusion influenced the SO 2 adsorption rate on both spent and regenerated AZ‐300 at different adsorption stages. The findings demonstrate that regenerated AZ‐300 is a viable, cost‐effective, and sustainable adsorbent for dry desulfurization, offering a promising alternative to conventional desulfurization methods.