ABSTRACT
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.
Subject(s)
Chemical Precipitation , Ferric Compounds/chemistry , Lignin/chemistry , Nanocomposites/chemistry , Colloids/chemistry , Hydrogen-Ion Concentration , Magnetic Phenomena , Nanocomposites/ultrastructure , Particle Size , Photoelectron Spectroscopy , Spectroscopy, Fourier Transform Infrared , Suspensions , X-Ray DiffractionABSTRACT
Isomerically pure 5,11-dibromo-2,8-dihexylanthra[2,3-b:76-b']dithiophene, a brominated analog of anthracenedithiophene (ADT), was prepared and utilized for a palladium catalyzed cyclopentannulation reaction with 3,3'-dimethoxy-phenylacetylene to give cyclopentannulated ADT (CP-ADTs). A further Scholl cyclodehydrogenation reaction gave contorted aromatics with large splay angles, low optical gaps, and low LUMOs.
