Even though phosphorus (P) is a vital element for all living organisms and crucial for global
food security, excess concentrations of it lead to detrimental environmental implications such as
eutrophication. With the concern for depleting resources and eutrophication caused by
wastewater, new methods must be developed for the removal and recovery of phosphorus. In this
work, carboxylic cellulose nanofibers (CNFs) were prepared using the zero-waste nitro-oxidation
process (NOP), where the resulting CNFs exhibited a degree of oxidation of 1.5 mmol/g. Iron
and cellulose-based hydrogel beads (CNF-Fe(III)) were prepared by crosslinking for removal
and recovery of P. The CNF-Fe(III) beads exhibited a nanoporous structure with high
crosslinking density. Batch adsorption studies showed optimal removal occurred with a pH range
of 2 – 7 with a contact time of 6 hours and removal efficiency of over 85%. Experimental data
characterized using FTIR, XRD, SEM-EDX, BET, and XRF indicates the adsorption mechanism
involved electrostatic interactions, hydrogen bonding, precipitation, and pore filling. To elucidate
the different paths of adsorption of phosphorus by CNF-Fe(III) hydrogel beads, DFT calculations
were performed. This study presents a novel sustainable material for the removal and reuse of
phosphate from wastewater.
