Preparation Of Soft Porous SiO₂@C Nanofibrous Membranes For Adsorption Of Bovine Serum Albumin

Presently, pharmaceutical proteins have become major contributors in immunodiagnostics, immunotherapy, and scientific research. However, the quality and yield of protein products are not able to meet the demand of market. Thus, much efforts have be taken to develop an effective and low cost approach to produce the high qualified proteins.Carbon nanofiber?CNF? as a typical nanoscale carbon based material is well known for its high temperature resistance, good chemical stability, excellent electrical conductivity, and large specific surface area. Benefiting from these advantages, various CNF based materials with functional interfaces and designed structures have been developed for different applications, such as energy storage electrodes, catalyst carriers, separation membranes and adsorbents. Until now, much efforts have been made to synthesis CNF materials, including the substrate method, chemical vapor deposition, vapor growth method, which are quite complex and hard to be scalable. Alternatively, electrospinning method has become a powerful and highly versatile technique to fabricating both organic and inorganic nanofibrous materials, as the electrospun nanofibers possess merits of extremely high aspect ratio, tunable structures and ease of scalable synthesis from various precursor polymers. Therefore, the electrospun CNF membranes has been developed as a promising candidate for high efficient protein separation owing to its high surface area, easy to be functionalized and chemical stability. However, in the conventional CNF, most of the pores are micropores?pore size < 1 nm?, which are invalid for the entrance of protein molecules?most are in the range of 1¹00 nm?. As a result, the adsorption capacity of CNF for proteins is quite difficult to be improved, limiting the practical use of CNF in proteins separation. More importantly, due to the brittle instinct of carbon compare with polymer based membranes, these CNF membranes often suffer from the low mechanical properties, which are essential for a separation membrane to be packed into devices. To date, there are only a few literatures report their efforts on fabrication of self-standing CNF membranes. However, these self-standing CNF membranes are still brittle and hard to recover from the deformations. Therefore, the enhancement of mechanical property of CNF membrane with more valid pores is a critical issue for its practical application in proteins separation.In this article, we demonstrate a novel strategy to fabricate a hierarchical porous CNF membrane with enhanced mechanical properties via multicomponent electrospinning, nano-doing method. In addition, an in situ nitrogen-doping approach was taken by reusing the emitted gases from the carbonization of PAN to activate the surface of CNF.The resultant SiO₂@CNF membrane was mechanical robust with an intriguing softness and shape memory behaviour like a polymer based membrane, and exhibits an intriguing shape memory property, which can be bended to a radius < 100 ?m without any fracture and recover from the deformation rapidly, which may be attributed to the presence of SiO₂ nanoparticles and graphitized carbon layers in carbon matrix, attributed to the “plasticizer” effect of the doped SiO₂ nanoparticles and the protogenetic graphitized carbon layers. Besides that, the SiO₂@CNF membrane exhibited a significantly improved adsorption capacity for bull serum albumin molecules?30±0.9 mg/g? and a high water permeability?15202 ± 1927 L/m2/h under 3 kPa driven pressure?.