Presence of activated carbon particles from waste walnut shell as a biosorbent in monoethanolamine (MEA) solution to enhance carbon dioxide absorption

Greenhouse effects are a natural phenomenon that plays a high role in shaping the climate system. In this research, MEA solution was used for CO2 capture in presence of activated carbon particles from waste walnut shells as a biosorbent. The process parameters including temperature, pressure, MEA concentration, and activated carbon were used in the central composite design (CCD) model. The absorption experiments were carried out in a laboratory setup at operational conditions including temperature in range of 20-60 °C, pressure in range of 3.5-9.5 bar, MEA concentration in range of 2.5-8.5 wt%, and active carbon amount in range of 0.3-0.9 g/L. The process responses including CO2 loading, the amounts of CO2 absorption, and absorption percentage were obtained in the range of 0.444-0.720 molCO2/molMEA, 0.294-0.687 mol/L, and 19.32-52.25%, respectively. The optimal value of CO2 loading was obtained at temperature of 30 °C, pressure of 5.19 bar, activated carbon of 0.75 g, and MEA concentration of 7.00 wt%. The optimum values of responses were obtained 0.531, 0.609 mol/L and 50.04% for maximum loading, absorption amount, and absorption percentage, respectively. From the results, carbon dioxide loading in MEA solution increases in presence of activated carbon particles.