(24d) Synthesis of Charged Lignin Nanoparticles and Its Applications As Adsorbent

Per- and poly-fluoroalkyl substances (PFAS), which are also called forever chemicals, are widespread in surface water, groundwater and drinking water in the United States. They are recalcitrant to present treatment techniques, accumulate in the human body over time and cause serious health problems. Challenges for the removal of PFAS from the water are low adsorption capacity, slow adsorption, and high cost of the adsorbent. Lignin, the most abundant low-cost aromatic polymer, is an underutilized polymer due to its heterogeneous structure. Lignin nanoparticles (LNPs) offer many opportunities for value-added applications due to their controllable size, spherical shape, large surface area, high surface charge, long-term dispersibility in water, and compatibility with other polymers. Since the majority of PFAS contain negative charges on their surface, electrostatic interaction between PFAS and adsorbent can be increased by synthesizing cationic adsorbents. In this study, cationized lignin was prepared and applied for PFAS capturing. Adsorption of PFAS was compared for technical lignin, cationic lignin, and cationic LNPs. Regeneration of lignin particles was performed by increasing the pH. The structural, morphological and adsorption properties were analysed and discussed using GPC, HPLC, FTIR, ¹H NMR, 2D HSQC NMR, ³¹P NMR, zetasizer, SEM, and others.