Lead adsorption with sulfonated wheat pulp nanocelluloses

Low-cost sorbents derived from abundant natural resources, industrial by-products, or waste materials are considered amongst the most viable novel materials for heavy metal removal. In this study, wheat straw pulp fine cellulosics were used as a biosorbent for the removal of Pb(II) in aqueous solutions after nanofibrillation and sulfonation pretreatments. The effect of the initial lead concentration, sorption time, and solution pH were studied, and the isothermal data were modeled with the Langmuir and Freundlich isotherm models. Pb(II) was adsorbed efficiently (1.2 mmol/g) from the model solution by sulfonated nanocelluloses which had a width between 5 and 50 nm and a sulfonic acid content of 0.45 mmol g−1. This adsorption capacity is comparable to those of commercial adsorbents. The Pb(II) adsorption onto nanofibrillated and sulfonated cellulosics followed the Langmuir isotherm model and showed rapid initial kinetics. Thus, nanofibrillated and sulfonated cellulosics are promising green alternatives for the recovery of metals from aqueous solutions.