Development and characterisation of dense lanthanum-based perovskite oxygen-separation capillary membranes for high-temperature applications

Mechanism and Compatibility of Pretreated Lignocellulosic Biomass and Polymeric Mixed Matrix Membranes: A Review

In this paper, a review of the compatibility of polymeric membranes with lignocellulosic biomass is presented. The structure and composition of lignocellulosic biomass which could enhance membrane fabrications are considered. However, strong cell walls and interchain hindrances have limited the commercial-scale applications of raw lignocellulosic biomasses. These shortcomings can be surpassed to improve lignocellulosic biomass applications by using the proposed pretreatment methods, including physical and chemical methods, before incorporation into a single-polymer or copolymer matrix. It is imperative to understand the characteristics of lignocellulosic biomass and polymeric membranes, as well as to investigate membrane materials and how the separation performance of polymeric membranes containing lignocellulosic biomass can be influenced. Hence, lignocellulosic biomass and polymer modification and interfacial morphology improvement become necessary in producing mixed matrix membranes (MMMs). In general, the present study has shown that future membrane generations could attain high performance, e.g., CO2 separation using MMMs containing pretreated lignocellulosic biomasses with reachable hydroxyl group radicals.

CaCox Zr1-x O3-δ Perovskites as Oxygen-Selective Sorbents for Air Separation

ABO_3-δ perovskites are ideal for high-temperature thermochemical air separation for oxygen production because their oxygen nonstoichiometry δ can be varied in response to changes in temperature and oxygen partial pressure [ p O 2 ]. Herein, the outstanding oxygen-sorption performance of CaCo_x Zr_1-x O_3-δ perovskites and their potential application as oxygen-selective sorbents for air separation is reported. In situ thermal X-ray diffraction was used to study the materials' structural changes in response to temperature variations in air and inert atmosphere. Temperature-programmed reduction was employed to elucidate the relationship between perovskite composition and redox property. O₂ sorption performance was evaluated by isothermal analyses at various temperature and p O 2 along with long-term absorption-desorption cycle tests. The high oxygen-sorption capacity was mainly attributed to Co at B-site, whereas partial substitution of Co by Zr enhanced the structural crystallinity and thermal stability of the perovskite. A stable oxygen production of 2.87 wt % was observed at 900 °C during 5 min-sorption cycles for 100 cycles.