Experimental Study of the Effect of Nanofluids Containing Activated Carbon Nanoparticles on Carbon Dioxide Absorption

Increasing greenhouse gases, especially carbon dioxide, are a serious threat to the environment and rising global temperature. One of the methods of separation and reduction of greenhouse gases is based on physical and chemical absorption by nanofluids. The main goal of this study is to investigate the effect of aqueous base nanofluids containing activated carbon nanoparticles synthesized from agricultural waste at different concentrations on CO2 absorption. For this purpose, the activated carbon nanoparticles were first synthesized from walnut shells, and the physicochemical properties of the synthesized nanoparticles were determined by FESEM, FT-IR, and BET analyses, and then the nanofluids were prepared at different concentrations of nanoparticles including 0.02, 0.05, and 0.1 wt. %. The effect of prepared nano-fluids on the carbon dioxide absorption at 35° C and pressures of 20, 30, and 40 bar were investigated in a high-pressure equilibrium cell with a magnetic stirrer and results are compared with CO2 absorption by pure water. The results showed that carbon dioxide uptake increased with increasing nanoparticle concentration and initial pressure. The maximum CO2 absorption occurred at 40 bar and 0.1 wt. % of nanoparticles, in which the CO2 absorption was 29% higher than pure water.