Fabrication of highly porous PMMA electrospun fibers and their application in the removal of phenol and iodine

Abstract

Highly porous polymethyl methacrylate (PMMA) fibers were fabricated via an electrospinning technique using a binary solvent system (8:2 dichloromethane:dimethylformamide) and controlled humidity. The electrospinning process was carried out in a closed hood under humid conditions (varying the humidity from 15 to 70 %). The effects of the concentration, electrospinning parameters, and humidity on the morphology of the PMMA fibers were assessed by field emission scanning electron microscopy (FE-SEM). The surface area, porosity, and mean interfiber pore size of membranes made from the fibers were measured with the Brunauer–Emmett–Teller (BET) method, and the diameter of the fibers was measured using an image analyzer. Nonporous and porous electrospun PMMA fibers exhibited concentration-dependent variations in their morphologies. No effect of the electrospinning parameters, such as the voltage and flow rate, was observed. The porosity of the PMMA fibers increased when the humidity was changed from 15 to 70 %. The porous PMMA fibers had a large surface area (139.0 m2/g) and a small interfiber pore size (34.8 A), along with an average fiber diameter of 2 μm. The capacities of the porous and nonporous fibrous membranes to adsorb iodine and phenol were tested. The large surface areas of the membranes led to excellent adsorption capacity of the porous PMMA fiber membrane (iodine: 203 mg/g; phenol: 3.73 mg/g), in contrast to the adsorption capacities of the nonporous PMMA fiber membrane (iodine:117 mg/g; phenol: 1.8 mg/g). A facile, easily accessible approach for fabricating porous fiber membranes is presented in this work, and it is believed that the product may find potential application—as a possible substitute for conventional material—in the removal of organic and inorganic pollutants from water.