Nanocomposites of Magnetically Retrievable Cellulose and Metal Oxide Frameworks for Efficiency in Concurrent Pollutant Removal

(https://doi.org/10.5281/zenodo.22184665)

सार

The complexity of industrial wastes has increased significantly with the increase in number of pollutants that are discharged in a single waste stream, and conventional single pollutant treatment processes have become largely ineffective. This scientific work offers a comprehensive study of the synthesis, characterization and application of magnetically recoverable metal-organic frameworks (MOF) and transition metal oxide (TMO) composites based on cellulose. The intrinsic biocompatibility, hydrophilicity and functional group density of nanocellulose makes these composite materials more suitable than unmodified metal-organic frameworks to overcome their structural vulnerability and tendency for agglomeration. The superparamagnetic iron oxide nanoparticles (SPIONs), primarily magnetite Fe3O4 particles, overcome the technical challenge of post-treatment separation of the solid adsorbents from the liquid solution by being easily recovered from the liquid by external magnetic field. The composites of MCNC presented significant specific surface area (Type IV isotherms and mesoporous structure) that leads to outstanding adsorption property. These materials have shown excellent performance for the simultaneous removal of heavy metal cations (e.g., Pb(II), Cu(II), As(III)), synthetic dyes (e.g., methylene blue, malachite green) and pharmaceutical micropollutants (e.g., tetracycline). The adsorption phenomenon in these complex multisolute systems is mainly described by pseudo-second order kinetic model and follows the Langmuir and extended Langmuir isotherm models indicating that the primary removal phenomenon is monolayer chemisorption. The synergy between electrostatic attraction, Lewis acid-base interactions, π-π stacking and hydrogen bonding allows distinct contaminants to bind to different active sites without the complete competitive exclusion of other contaminants, mechanistically. Moreover, thermodynamic evaluations validate the spontaneity of the adsorption mechanism. Due to their outstanding chemical stability and reusability, these magnetic composites are a highly promising, scalable and sustainable approach for comprehensive purification of complex wastewater systems.