Thermally Treated Alum Sludge as Novel Adsorbent of Carbon Dioxide (CO2)

Abstract

Dewatered alum sludge from drinking water treatment plants was exploited as carbon dioxide (CO2) adsorbent in a fixed-bed column system. In this study, the effects of 6 parameters including particle size of adsorbent, heat treatment of adsorbent adsorbents dosage, adsorption temperature, flow rate of adsorbate and CO2concentration on the fixed-bed adsorption of CO2were investigated using Response Surface Methodology (RSM). The experimental data was successfully fitted with the regression model to identify the significant parameters and predict the optimum value parameters for maximizing CO2adsorption capacity. Analysis of Variance (ANOVA) revealed that CO2concentration was the most significant factor influenced the CO2adsorption capacity. The experimental data of CO2adsorption capacity were in a good agreement with the predicted data from the regression model. The highest fixed-bed CO2adsorption capacity of 10.028 mmol.g-1(441.24 mg.g-1) was achieved using 1 g of 450-500 pm of 800°C thermally treated alum sludge at CO2concentration of 8000 mg.L-1with a flow rate of 90 mL.min-1at 25°C. The results suggested that thermally treated alum sludge is a promising solid adsorbent for CO2capture.