CO2 capture by adsorption in post combustion processes

Global concentration of CO2 in the atmosphere is increasing rapidly. CO2 emissions have huge impact on global climate change. Therefore, efficient CO2 emission abatement strategies such as Carbon Capture and Storage (CCS) are required to combat this phenomenon. There are three major approaches for CCS: - Post-combustion capture; - Pre-combustion capture; - Oxyfuel process. Post-combustion capture offers some advantages in terms of cost as existing combustion technologies can still be used without radical changes on them. This makes post-combustion capture easier to implement as a retrofit option compared to the other two approaches. Therefore, post-combustion capture is probably the first technology that will be deployed on a large scale. The aim of this work is to study the adsorption equilibrium of CO2, CH4 and N2 in zeolite 5A at 40ºC. For this, experiments were performed to determine the isotherms of adsorption of CO2, CH4 and N2 near 40ºC with the conditions of the post-combustion capture processes. It has been found that the 5A zeolite adsorbs a significant quantity of CO2 values of about 5 mol/kg at a pressure of 5 bar.

A comparison of the bioactivity and phytochemical profile of three different cultivars of globe amaranth: red, white, and pink

The phytochemical profiles and bioactivities of red, white and pink globe amaranth (Gomphrena haageana K., Gomphrena globosa var. albiflora and Gomphrena sp., respectively), much less studied than the purple species (G. globosa L.), were compared. The chemical characterization of the samples included the analysis of macronutrients and individual profiles of sugars, organic acids, fatty acids, tocopherols, and phenolic compounds. Their bioactivity was evaluated by determining the antioxidant and anti-inflammatory activities; the absence of cytotoxicity was also determined. Red and pink samples showed the highest sugar content. Otherwise, the white sample gave the highest level of organic acids, and together with the pink one showed the highest tocopherol and PUFA levels. Quercetin-3-O-rutinoside was the major flavonol in white and pink samples, whereas a tetrahydroxy-methylenedioxyflavone was the major compound in the red variety, which revealed a different phenolic profile. The pink globe amaranth hydromethanolic extract revealed the highest antioxidant activity, followed by those of red and white samples. The anti-inflammatory activity was more relevant in red and pink varieties. None of the samples presented toxicity in liver cells. Overall, these samples can be used in bioactive formulations against inflammatory processes and in free radical production.