Green adsorbent for CO2 adsorption: MgO impregnated palm kernel shell-based activated carbon

This study utilized palm kernel shells (PKS), a type of biomass, to synthesize chemically modified activated carbon in order to enhance its efficacy in adsorbing carbon dioxide (CO2). To enhance the adsorption efficiency, the activated carbon derived from PKS has undergone chemical activation with potassium hydroxide (KOH) and impregnated with magnesium oxide (MgO). The physicochemical characterization, CO2 adsorption performance, isotherm and thermodynamics properties were evaluated. The characterization analysis shows that PKS-MgO exhibited a surface area of 418 m(2) g(-1) and a well-formed mesopores structure with pore diameter and volume of 2.8 nm and 0.294 cm(3) g(-1), respectively. The FTIR analysis shows the presence of hydroxyl group (-OH), amino group (-NH2), carbonyl group (C=O), metal-oxygen bond (Mg-O). The result revealed that PKS-MgO has the highest CO2 adsorption capacity of 104.74 mg g(-1) at lowest temperature of 25 degrees C and 5 bar. Subsequently, the adsorption capacity has been determined as 74.37 mg g(-1) at 50 degrees C and 51.93 mg g(-1) at 75 degrees C, respectively. Langmuir model fitted the data the best at 25 degrees C (R-2 = 0.978). On the other hand, he Temkin isotherm showed the best accuracy at 50 degrees C (R-2 = 0.986) and 75 degrees C (R-2 = 0.989). The isotherm study suggests that adsorption primarily occurs by homogeneous monolayer adsorption. In summary, the findings suggest that chemically modified palm kernel shells show potential for CO2 adsorption. This approach also aligns with circular economy principles, emphasizing the sustainable utilization of biomass resources and provide solutions for environmental concerns.