Experimental strategy for the preparation of adsorbent materials from torrefied palm kernel shell oriented to CO2 capture.

In this study, an experimental strategy to obtain biochar and activated carbon from torrefied palm kernel shell as an efficient material for CO2 removal was evaluated. Biochar was obtained by slow pyrolysis of palm kernel shell at different temperatures (350 °C, 550 °C, and 700 °C) and previously torrefied palm kernel shell at different temperatures (220 °C, 250 °C, and 280 °C). Subsequently, activated carbons were prepared by physical activation with CO2 from previously obtained biochar samples. The CO2 adsorption capacity was measured using TGA. The experimental results showed that there is a correlation between the change in the O/C and H/C ratios and the functional groups -OH and C=O observed via FTIR in the obtained char, indicating that both dehydration and deoxygenation reactions occur during torrefaction; this favors the deoxygenation reactions and makes them faster through CO2 liberation during the pyrolysis process. The microporous surface area shows a significant increase with higher pyrolysis temperatures, as a product of the continuous carbonization reactions, allowing more active sites for CO2 removal. Pyrolysis temperature is a key factor in CO2 adsorption capacity, leading to a CO2 adsorption capacity of up to 75 mg/gCO2 for biochar obtained at 700 °C from non-torrefied palm kernel shell (Char700). Activated carbon obtained from torrefied palm kernel shell at 280 °C (T280-CHAR700-AC) exhibited the highest CO2 adsorption capacity (101.9 mg/gCO2). Oxygen-containing functional groups have a direct impact on CO2 adsorption performance due to electron interactions between CO2 and these functional groups. These findings could provide a new experimental approach for obtaining optimal adsorbent materials exclusively derived from thermochemical conversion processes.

Kinetic-conceptual model of the hydrolysis of bovine plasma proteins - ALCALASE® 2.9L: The role of inhibition by product.

In the present work, the inhibitory effect of the peptide fractions, obtained through enzymatic hydrolysis of bovine plasma was evaluated, on the enzyme used in the reaction (Alcalase 2.4 L). In this sense, Ultra-filtered peptide fractions of different molecular sizes (A: Fraction>10; B: Fraction 10-3 kDa; and C: Fraction <3 kDa), were used to verify the impact on the total hydrolysis rate. The Fractions between 3 and 10 kDa were refined to fit a conceptual kinetic model which considers inhibition by product and substrate. Additionally, the inactivation of the enzyme through the reaction time was evaluated and its effects incorporated into the model. It was shown that some peptides released in the successive stages of the reaction can in turn inhibit the activity of the hydrolyzing enzyme. The model evaluated suggests a time-varying expression of inhibition parameters as a function of the initial substrate concentration in the reaction. This is based on the kinetic changes of the product profiles for each reaction time in the evaluated operating conditions (S0 variable). A greater inhibitory effect due to the products is evidenced when the reaction occurs with a higher load of the initial substrate (S0 = 20 g/L).

Release of phenolic compounds from fermented cocoa powder during fast heating in a novel hot plate reactor.

This article studies the release of phenolic compounds during cocoa heating under vacuum, N2, and air atmospheres, and proposes fast heating (60 °C • s-1) as a methodology that allows the release of polyphenols from fermented cocoa powder. We aim to demonstrate that gas phase transport is not the only mechanism to extract compounds of interest and that convective-type mechanisms can facilitate the process by reducing their degradation. The oxidation and transport phenomena were evaluated both in the extracted fluid and in the solid sample during the heating process. Polyphenols transport phenomena were assessed based on the fluid (chemical condensate compounds) that was collected cold with an organic solvent (methanol) in a hot plate reactor. Out of all the polyphenolic compounds present in cocoa powder, we assessed specifically the release of catechin and epicatechin. We found that high heating rates combined with vacuum or N2 favor the ejection of liquids; then, it is possible to extract compounds such as catechin-which is dissolved/entrained and transported in the ejected liquids-and avoid degradation phenomena.