Kunasundari
Abstract
In this paper, functionalization of multiwall carbon nanotubes (MWCNTs) using phosphoric acid (H34) was attempted. Based on the One Factor at a Time (OFAT) analysis, 8 M of H3PO4, 8 h of reflux time and 80 °C were identified as an ideal condition for the acid oxidation process. Successful functionalization of MWCNTs using H3PO4 was revealed from Fourier Transform Infrared Spectroscopy (FTIR) peaks and Scanning Electron Microscope (SEM) images. The resulting f-MWCNTs were immobilized with cellulase via adsorption. The optimum temperature for free cellulase was at 50 °C and for immobilized cellulase was at 60 °C. The optimum pH was at 5 for both free and immobilized cellulase. Higher thermal stability was achieved with immobilized cellulase in which 39% activity still was retained at 80 °C compared to free cellulase. Reusability study of immobilized cellulase depicted 28% of remaining activity after 5th cycle of analysis using model substrate (filter paper Whatman No. 1). These results suggest that H3PO4 which is a mild acid is a promising substitution for functionalization of MWCNTs.
doi: 10.17756/nwj.2023-112
Citation: Yasmin HAN, Rao T, Naresh S, Shuit SH, Kunasundari B. 2023. Functionalization of Multiwall Carbon Nanotubes (MWCNTS) using Phosphoric Acid for Immobilization of Cellulase. NanoWorld J 9(1): 15-22.