2.2. Carbon dioxide absorption studies
The different studies carried out in this work were performed in a bubble column reactor with a square geometry (side length = 4 cm; height = 65 cm) made in methacrylate and with a working volume of liquid phase of 0.9 L. The gas phase was fed in bubbles shape using a five-holes sparger built in Teflon®. This phase consisted on pure carbon dioxide saturated with water to avoid the influence of other mass transfer phenomena upon carbon dioxide mass transfer rate. The gas flow rate (QG) range used in this work was 0.1-0.3 L·min-1. These studies were based on the analysis of absorption rate and carbon dioxide loading using different reagents at varied concentrations and gas flow rates. The inlet and outlet gas flow rates were controlled and measured with two mass flow controllers (Alicat Scientific MC-5SLMP-D) previously calibrated by the supplier for the gas employed in these experiments at the working range for flow rates and pressures, thus allowing the calculation of the absorbed flow rate of carbon dioxide (qa). Also, Flow Vision SC software package (Alicat Scientific) was used to record the carbon dioxide flow rate during the experiments. The working regime was continuous in relation to the gas phase and batch regarding the absorbent liquid one.