Design and fabrication of electrospun mixed-matrix multi-layered membranes containing tri-n-octylphosphine oxide for efficient adsorption of p-cresol

In this study, various types of mixed-matrix cellulose triacetate (CTA) fibrous membranes were prepared by a combined electrospinning and electrospraying process, in which tri-n-octylphosphine oxide (TOPO) powders were incorporated on the surface of the fibers to remove uremic toxin p-cresol by adsorption. The morphology, chemical composition (element analysis), and textural properties of the prepared fibrous membranes were first analyzed. The adsorption ability of various fibrous membranes for p-cresol in synthetic serum was then studied in batch experiments at pH 7.4 and 37 °C. It was seen that the loose structure of the electrospun fibrous membranes was beneficial to the rate of adsorption and the position where the TOPO stayed on the fibers played a crucial role in the availability of TOPO and hence the adsorption performance. The maximum adsorption of p-cresol was 6.45 mmol per gram of TOPO, highlighting the adsorption ability of as-prepared mixed-matrix membranes. Moreover, the electrospun TOPO-coated fibers covered with a thin layer of the electrospun CTA fibers largely improved cell viability. The present results have demonstrated the application potential of electrospun/sprayed mixed-matrix fibrous membranes with TOPO for efficient adsorption of p-cresol.