Fabrication of a Lignin-Based Magnetic Nanocomposite Adsorbent to Recover Phosphorus in Water for Agricultural Reuse

Abstract

Phosphorus (P) is an essential nutrient for crops, but its excess in discharge water harms both surface water and groundwater quality. A cost-effective and eco-friendly adsorbent is desirable to meet circular economy criteria by effectively removing P from water and being safely recycled for agricultural use. Thus, this study aims to synthesize an amine-functionalized magnetic lignin nanocomposite biosorbent by first grafting poly­(ethyleneimine) on epoxidized lignin followed by coprecipitation with iron. This biosorbent shows an adsorption performance of 43 mg g–1, which is 20 times greater than the unmodified lignin reported in a previous research study and six times more than the magnetic iron metal. A series of characterization methods confirm the chemical features and the formation of a nanostructure. The pH, coexisting anions, and salt concentrations affect the P removal efficiency. The mechanism studies show that the electrostatic interaction between NH3 + functional groups and P, surface precipitation, and ligand exchange all count for P removal, which indicates the heterogeneous adsorption of P onto the sorbent surface by both chemisorption and physisorption. The seedling study confirms that the nanocomposite after P adsorption has better root development and biomass accumulation as a recycled fertilizer.

Selective and efficient removal of phosphate from aqueous solution using activated carbon-supported MgFe 2 O 4 -layered double hydroxide (LDH) hierarchically porous nanocomposite

“…The corresponding best-fit kinetic model parameters are provided in Table 3. Both the pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic data models fitted the experimental data well with the coefficient of determination values of r 2 ≃ 0.98 and r 2 ≃ 0.97, respectively suggesting that the adsorption process is complex [67]. As a matter of fact, both chemisorption and physisorption processes may coexist, and either monolayer or multilayer adsorption may occur, still, the slightly higher coefficient of determination value of pseudo first order suggests that physisorption was the predominant mechanism in the adsorption system, which involves the sharing of electrons and ion-exchange between phosphate ions and the active sites on the AC@ MgFe2O4-LDHs composite [68].…”

Biowaste-Derived, Hyperbranched Dendritic EDTA Analogue as an Anionic Biochelator with Superior Metal Affinity

“…In particular, the particles of L-EDTA-Cu were aggregated together with a brighter color in comparison with those of the unloaded L-EDTA. , The TEM images and SEAD patterns (Figure a2,a3,b2,b3) present evidence for the crystalline structure of LA with a d-spacing of 1.99 °A. The SEM and SEAD patterns (Figure c2,c3,d2,d3) presented evidence of the formation of multiple nanolayer polycrystalline lattices for L-EDTA . It is known that the hyperbranched polymer usually has a lattice or cage structure that traps or contains guest molecules, e.g., metal.…”

“…The SEM and SEAD patterns (Figure 2 c2,c3,d2,d3) presented evidence of the formation of multiple nanolayer polycrystalline lattices for L-EDTA. 34 It is known that the hyperbranched polymer usually has a lattice or cage structure that traps or contains guest molecules, e.g., metal. Obviously, the original lignin is not a lattice structure.…”

Functionalized Alkaline Lignin for Removal of Lead in Aqueous Solution

“…The modified lignin showed several cavities and cracks due to the clogging of 5-sulfosalicylic molecules on lignin surfaces. In addition, Li et al [14] also discovered changing morphology of lignin from an irregular shape to a rough and obscure surface after it was modified with polyethyleneimine (PEI). They found morphological changes due to the PEI polymer coating on the lignin surface.…”