Facile fabrication and characterization of kraft lignin@Fe3O4 nanocomposites using pH driven precipitation: Effects on increasing lignin content

• Published in: International journal of biological macromolecules Vol. 181; pp. 313 - 321
• Main Authors: Petrie, Frankie A., Gorham, Justin M., Busch, Robert T., Leontsev, Serhiy O., Ureña-Benavides, Esteban E., Vasquez, Erick S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.06.2021
• Subjects: Fe3O4; Kraft lignin; Lignin@Fe3O4 nanocomposites; Fe3O4; Lignin@Fe3O4 nanocomposites; Kraft lignin
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.03.105

This work offers a facile fabrication method for lignin nanocomposites through the assembly of kraft lignin onto magnetic nanoparticles (Fe3O4) based on pH-driven precipitation, without needing organic solvents or lignin functionalization. Kraft lignin@Fe3O4 multicore nanocomposites fabrication proceeded using a simple, pH-driven precipitation technique. An alkaline solution for kraft lignin (pH 12) was rapidly injected into an aqueous-based Fe3O4 nanoparticle colloidal suspension (pH 7) under constant mixing conditions, allowing the fabrication of lignin magnetic nanocomposites. The effects of increasing lignin to initial Fe3O4 mass content (g/g), increasing in ratio from 1:1 to 20:1, are discussed with a complete chemical, structural, and morphological characterization. Results showed that nanocomposites fabricated above 5:1 lignin:Fe3O4 had the highest lignin coverage and content (>20%), possessed superparamagnetic properties (Ms ≈ 45,000 A·m2/kg2); had a negative surface charge (−30 mV), and formed multicore nanostructures (DH ≈ 150 nm). The multicore lignin@Fe3O4 nanocomposites allowed rapid magnetically induced separations from suspension. After 5 min exposure to a rare-earth neodymium magnet (1.27 mm × 1.27 mm × 5.08 mm), lignin@Fe3O4 nanocomposites exhibited a maximum methylene blue removal efficiency of 74.1% ± 7.1%. These nanocomposites have potential in magnetically induced separations to remove organic dyes, heavy metals, or other lignin adsorbates. [Display omitted] •Kraft lignin@Fe3O4 nanocomposites were prepared via a pH-driven aqueous-based method.•A multicore structure was obtained with Fe3O4 nanoclusters and lignin shells.•Above a 5:1 lignin:Fe3O4 mass ratio, nanocomposite properties remain unchanged.•Methylene blue was adsorbed and magnetically separated with a low strength magnet.