After cooling down to 25°C, we have measured again the permeance using helium (Figure 14). As illustrated by this figure, the permeance of the carbon membrane towards helium is increased after the membrane was Aurora Kinase inhibitor exposed to higher operating-temperature conditions. Our assumption is that the membrane underwent a microstructural evolution during the high-temperature measurement. In order to confirm the latter, the
membrane surface was analyzed by SEM after the experiment, done at 200°C (Figure 14). We can clearly conclude from the images of Figure 9 that the surface of the membrane underwent a microstructural evolution upon heating which yielded to an increase of its surface roughness. Fracture surface view analysis did not reveal any significant evolution of the membrane thickness. Figure 14 Permeances of helium at different temperatures using the same membrane. Permeances at 25°C (T01), at 25°C but after an exposure at 100°C (T02), and the same membrane after an exposure at 200°C (T03). Conclusions Hydrothermal carbonization process of beer wastes (Almaza Brewery) yields a biochar and homogeneous carbon-based nanoparticles (NPs). Carbohydrates, released by the wastes in water, are supposed to play a role in the formation mechanism of the NPs, and further experiments will be driven in the future to
elucidate the latter. The NPs have been used to prepare Ulixertinib carbon membrane on commercial alumina support. As evidenced in water filtration experiments, there is a quasi-dense behavior of the membrane with no measurable water flux below an applied pressure of 6 bar. Gas permeation tests were conducted and gave remarkable results: (1) the existence of a limit temperature of utilization of the membrane is below 100°C in our experimental conditions; (2) an evolution of the microstructure of the carbon almost membrane with the operating temperature yielded to improvement in its gas separation performances; (3) the
permeance of the gas is temperature dependent and should be driven by a Knudsen diffusion mechanism; and (4) the He permeance is increasing with the applied pressure in entrance on the system, whereas N2 and C02 permeances are stabilizing in the same conditions. This result yields an increase of the selectivity He/N2 and He/CO2 with the applied pressure. The obtained selectivity values are below the ones reported in the literature but further experiments are in progress in order to improve this value by optimizing the membrane microstructure and porosity. These promising results made biomass-sourced HTC-processed carbon membranes promising candidates as ultralow-cost and sustainable membranes for gas separation applications. Since He exhibits a kinetic diameter closed to that of H2, applications as membrane for H2 separation can be envisaged, for instance, for fuel cell applications.