Enhanced Recovery of Aviation Biofuel Precursor Isoprenol Using Nanocarbon-Immobilized Membrane-Based Membrane Distillation

This paper demonstrates enhanced removal and recovery of isoprenol by employing nanocarbon-immobilized membranes (NCIM) for air-sparged sweep gas membrane distillation (AS-SGMD). The isoprenol flux, separation factor, and mass transfer coefficient obtained for NCIM were significantly higher compared to plain PTFE membranes under various experimental conditions. Among the two types of nanocarbon-immobilized membranes, namely, graphene oxide-immobilized membrane (GOIM) and carbon nanotube-immobilized membrane (CNIM), GOIM exhibited better performance in terms of isoprenol flux and separation factor. Compared to a plain PTFE membrane, GOIM showed a 71% increase in the isoprenol flux and a 52% increase in the separation factor, achieving a maximum separation factor of 3.6 and flux of 0.68 kg/m² h at a temperature of 80 °C. Enhanced performance of NCIM is attributed to the alteration of the partitioning effect through preferential sorption of the organic moiety, followed by fast desorption from nanocarbon surfaces. The demonstrated enhancements to both membrane flux and isoprenol concentration factor create the potential for significant capital and operational cost savings if such membranes are deployed at a commercial scale.