Preparation of Sodium-Activated Natural Bentonite Clay Incorporated Cellulose Acetate Nanofibres by Free Surface Electrospinning and Its Proposed Applications

Incorporating activated bentonite clay (BC) into electrospun nanofibres is an established strategy for modulating adsorption behaviour. In the present study, we have provided a comprehensive review of electrospun nanofibres from different types of polymers with synthesized montmorillonite clays (MMT). Loading activated natural bentonite clay (BC) into any type of polymer can improve the adsorption property of electrospun nanofibres, but BC must be well dispersed, suspended and loaded to achieve any benefit. Naturally occurring calcium BC was completely activated to sodium BC with a 4 wt.% sodium carbonate (Na2CO3)/BC ratio. High throughput composite nanofibrous fabrics were produced from cellulose acetate (CA)/BC spinning solutions using free surface electrospinning and the effect of BC loadings on viscosity, surface tension and electrical conductivity prior to spinning were studied. It has been found that the higher the BC loading rate and thus higher viscosity and surface tension, the higher the applied voltage and the lower the rotation speed of the wires electrode were required in order to get the highest productivity accompanied with electrospinning stability. Chemical and thermal analyses were conducted on as-spun fibres, and SEM and TEM revealed a nanofibrous morphology consisting of an inter-penetrating network of fibres and semi-spherical features resembling jellyfish with an internal core of BC. The problem with the existing adsorption process and the need for the change in the texture of the separation layer that controls the performance of the resultant membrane in terms of flux and selectivity were discussed and directed. We believe that this study may pave the way for further use of electrospun nanofibres loaded with clay in a wide variety of environmental and medical applications.