Multifunctional Cellulose-Based Adsorbent from Waste Wood Wool for Heavy Metal Removal and Bacterial Disinfection: Insights into Adsorption Behavior, and DFT Calculations

The present study demonstrates the isolation of pure cellulose (CU) from Cedrus deodar a (C. deodara) wood wool. Further, CU and modified mercaptobenzothiazole-functionalized CU (CU-MBT) were evaluated for adsorptive removal of Hg(II), Pb(II), Cd(II) ions and bacterial strains from water. Advanced characterizations through TGA, HR-TEM, FE-SEM, FTIR, XRD, EDX and XPS were performed to analyze the adsorbents. The adsorption kinetics of CU and CU-MBT followed the pseudo-second-order model with high regression coefficients (0.99) for Pb(II), Cd(II), and Hg(II). At pH 6 and pH 7, the thiol-functionalized CU-MBT displayed better adsorption capacities i.e. 185.18 mg/g, 178.57 mg/g, and 140.84 mg/g for Pb(II), Cd(II), and Hg(II) respectively. Several oxygen and sulphur-containing groups present at high densities in the CU-MBT are attributed to impressive adsorption properties towards Hg(II), Pb(II), Cd(II). Further, DFT calculations validated the stability and reactivity of CU and CU-MBT by utilizing their structural characteristics. Later, in the antibacterial analysis, the developed adsorbents revealed good antibacterial properties. In conclusion, CU-MBT has considerable calibre to act as an effective adsorbent in removing Pb(II), Cd(II), and Hg(II) as well as bacterial species from water, demonstrating its potential in water treatment.