Green Synthesis of Size-Controllable Polyfurfuryl Alcohol Nanospheres as Novel Bio-adsorbents

Nanomaterials derived from biomass preparation exhibit potential applications in the field of environmental protection. However, the synthesis methods still have some problems, including being a time-consuming and complex process and causing secondary pollution. In this work, polyfurfuryl alcohol (PFA) nanospheres are synthesized via a green method that uses water as the solvent, sodium dodecyl sulfate as the stabilizer, and p- benzenesulfonic acid monohydrate as the acid catalyst. In addition, the filtrate remained capable of preparing uniform nanospheres in five subsequent runs. Moreover, the size of PFA nanospheres could be regulated from 40 to 800 nm. The small PFA nanospheres provide a large surface area, suggesting more adsorption sites. PFA nanospheres are used first as novel bio-adsorbents for cationic dye (methylene blue) removal because of their abundant oxygen-containing functional groups and negative potential. Synthesis parameters and adsorption conditions affecting cationic dye removal, sorption mechanisms, and kinetics were studied. Results suggest that the synergistic effect of electrostatic attraction, pi-pi interactions, and hydrogen bonding contributes to the maximum adsorption capacity as high as 343.3 mg/g. Furthermore, the PFA nanospheres exhibited good regenerative properties. This work paves the way for the green and sustainable preparation of biomass furfuryl alcohol nanospheres.