Fabrication and optimization of curcumin-multiwalled carbon nanotube (C-MWCNT) conjugate reinforced electrospun polyacrylonitrile membrane for water treatment applications.

In the recent times, one of the most crucial tasks related to water resources is the treatment of polluted water. This study reports the development of a functionalized nanofibrous membrane with enhanced filtration performance, heavy metal removal, and photocatalytic dye degradation for the effective treatment of contaminated water. The nanofibrous mats were developed by the process of electrospinning using a polymeric solution of polyacrylonitrile (PAN) reinforced with curcumin-multiwalled carbon nanotube (C-MWCNT) conjugate. The experimental trials for membrane fabrication were adapted based on the design of experiments (DoE) approach by making use of the Box-Behnken design (BBD) for a three-variable system, a component of response surface methodology (RSM). The three variable parameters selected for optimization of the electrospinning process were the dopant concentration (in weight percentage), the flow rate (in millilitre per hour), and the spinning time (in hours), respectively, and a total of 15 fibrous membranes were fabricated. The SEM analysis of the fabricated membranes revealed alterations in the surface morphology of the fibrous mats with variations in the electrospinning parameters. The infrared spectrum of the fibrous mats, validated the incorporation C-MWCNT conjugate in PAN, thereby confirming the formation of PAN/C-MWNCNT membrane. The mean flow pore size and breaking force of the PAN/C-MWCNT membranes was also obtained using a universal testing machine (UTM) and porometer, respectively. To choose the best membrane for efficient filtration experiments, the performance of each of the prepared membranes was assessed in terms of solute rejection percentage (SR%), permeate flux (PF), and pure water flux (PWF). The statistical analysis of the assessed parameters in accordance with the membranes prepared was done using the MINITAB software, and the three-dimensional (3D) surface plots were constructed using the STATISTICA software to visualize and validate the relation between each of the electrospinning parameters and the corresponding membrane performance characteristics. Similarly, the potential of the electrospun membranes for efficient heavy metal ion removal and photocatalysis were also tested independently and the optimal electrospinning parameters were determined for the same. Based on the results, it was observed that the PAN/C-MWCNT membranes could serve as potential candidates for the treatment of polluted water.