One-pot synthesis of PEI-functional magnetic nano-Sm2O3 adsorbent (PEI/Fe3O4-Sm2O3) for efficient glyphosate adsorption performance

Based on the unique affinity interaction between amino (NH 2 ) and metal oxides (MOs) with phosphate groups (PO 4 3− ), herein, Fe 3+ , Fe 2+ and Sm 3+ were respectively usedas metal ion source, polyethyleneimine (PEI) as functional monomer, together with ammonia as precipitant to prepare a novel PEI-functional magnetic rare earth samarium metal oxide composite nano material (PEI/Fe 3 O 4 -Sm 2 O 3 , denoted as PFS) using a “one pot method” for the adsorption study of simulating high concentration glyphosate (GLY) in waterbodies emergency pollution. Consequently, the PFS adsorbent was characterized and analysed successfully using techniques such as SEM, TEM, EDS, BET, XRD, XPS, VSM and so on. A single-factor adsorption experiment was performed to explore how factors like the initial concentration of GLY ( C 0 ), solution pH, adsorbent dosage ( m ), and oscillation time affect PFS's adsorption of GLY. Under the optimized conditions, the adsorption of GLY by PFS could reach up to 92.3 % with a maximum saturated adsorption capacity Q max  = 178.5 mg/g. Furthermore, PFS had a certain recyclability after 4 cycles adsorption-desorption of GLY. In addition, the Langmuir model ( R 2  = 0.962) could be better described the adsorption process as examined by isothermal adsorption modelling. The kinetic model fit the pseudo-secondary dynamics well ( R 2  = 0.999), and the adsorption process was spontaneous and endothermic. Besides, we the possible mechanisms of GLY adsorption by PFS were preliminarily explored, which was synergistically promoted by three main adsorption mechanisms, including electrostatic interaction and hydrogen bonding as well as covalent bonding. Morever, PEI-functional magnetic nano-Sm 2 O 3 with high affinity was first used as an adsorbent for GLY due to the synergistic interaction between Sm 2 O 3 and -HPO 3 − , NH 4 + and -HPO 3 − /-COO − . Finally, PFS was used to remove residual GLY in real world water environment (Baiyun lake, Siya river and farmland water) using a convenient and rapid magnetic separation process. The adsorption and removal of GLY in adding standard samples experiments on different substrate waters were above 95 % and could avoid the adverse effects of GLY residues on the aquatic environment. The above results indicated that PEI/Fe 3 O 4 -Sm 2 O 3 , which is a new and excellent nano adsorbent, exhibits a excellent adsorption capacity for GLY, demonstrating a large potential for practical water applications, especially for urgently water bodies polluted with high concentrations of GLY.