Recycling of hydrogen tolerant La0.6Ca0.4Co0.2Fe0.8O3–d oxygen transport membranes with integrated life cycle assessment for plasma-assisted CO2-conversion

Abstract

In this study, a recycling approach was adapted for the hydrogen tolerant La_0.6Ca_0.4Co_0.2Fe_0.8O_3–d (LCCF_6428) oxygen transport membranes that have great potential in plasma-assisted CO₂ conversion techniques for producing industrial fuels such as methanol. The major focus was the incorporation of sustainability measures such as integrating life cycle assessment (LCA) into the materials development at an early stage to study and compare the environmental feasibility of the recycled membrane with the primary membrane. The aim was also to ensure reduced resource depletion of critical raw materials such as cobalt and lanthanum by means of recycling. It consisted of microwave-assisted dissolution of the membrane followed by ultrasonic spray synthesis. The recycled membrane exhibited at least 83 % of the oxygen permeability of the primary membrane and maintained hydrogen tolerance up to 600 °C for 25 h which is a remarkable result for LCCF_6428 in terms of potentially enhancing its life span. As per the LCA, recycling did result in lower resource depletion. However, the recycled LCCF had a higher overall environmental impact compared to the primary LCCF, mainly due to increased electricity consumption during recycling. These results accentuate the need for a transition towards more efficient processes accompanied by cleaner and renewable sources of energy and critically indicate integration of LCA into materials development to establish the sustainability profile of materials.