Evoshell PLA/PCL: eggshell-derived biocomposite membranes for oil/water remediation

Oil-in-water (O/W) emulsions in domestic and industrial effluents pose a multifaceted challenge due to their stability, multi-droplet size, and low resistance to traditional treatment methods. In this study, composite microfiltration membranes were developed to separate oil droplets from O/W emulsions efficiently. Fine particles from chicken eggshell waste were chemically modified via esterification and directly incorporated into a polylactic acid/polycaprolactone (PLA/PCL) matrix, forming a homogeneous, porous, and asymmetric membrane with a micro/nano-hierarchical structure that enhances surface hydrophobicity. The membranes were fabricated using a combination of plate casting, non-solvent-induced phase separation (NIPS), acid treatment, and ambient drying. The membranes were comprehensively characterised, including chemical structure, morphology, crystallinity, mechanical strength, and surface wettability. The filtration performance was evaluated using an O/W mixture and a surfactant-stabilised O/W emulsion. This work demonstrates a sustainable approach to valorising biowaste eggshells while providing a high-performance membrane for efficient oil/water separation.