High charge density cationic wood for efficient I-/IO3- capture via electrostatic and redox interactions

Two cationic functional woods with highly density nitrogen functional group are synthesized. • Q-BW and Gua-BW exhibit the fast uptake adsorption kinetics (within 5 min) of I - and IO 3 - through strong electrostatic interactions. • Gua-BW containing guanidine groups achieves roughly ten times the maximum IO3- sorption capacity of Balsa wood via electrostatic and redox. • Gua-BW, derived from renewable Balsa wood with low cost, displays excellent adsorption capacity and favorable reusability. Compared to conventional adsorbent carriers, Balsa wood (BW) has the superiority of being low-cost and environmentally friendly. Herein, quaternary ammonium-functionalized Balsa wood (Q-BW) and guanidine-functionalized Balsa wood (Gua-BW), as two cationic functional woods, are synthesized directly from natural Balsa wood via grafting high-density nitrogen-containing groups. The two modified woods exhibited remarkably high adsorption rates for I - and IO 3 - through electrostatic interactions, reaching adsorption equilibrium within 5 min. The maximum adsorption performance reached 120 mg·g −1 for I - and 220 mg·g −1 for IO 3 - , which was 10 times higher than that of natural Balsa wood. Notably, grafting with guanidino groups endows Gua-BW with redox ability, thereby significantly enhancing its adsorption performance for IO 3 - . Furthermore, Gua-BW demonstrates excellent reusability, retaining stable adsorption efficiency after 5 cycles. As a cationic porous wood material with ultrahigh positive charge density, Gua-BW possesses properties of being green, low-cost, renewable, and having significantly higher adsorption rates for I - and IO 3 - , which provides a new approach for applications in the field of iodine-containing wastewater purification. The synthetic pathway of two cationic wood material and adsorption of iodide ions and iodate ions. Download: Download high-res image (199KB) Download: Download full-size image