Adsorption of Pb(II) from Aqueous Solutions Using Nanocrystalline Cellulose/Sodium Alginate/K-Carrageenan Composite Hydrogel Beads

Based on the excellent performances of nanocrystalline cellulose, sodium alginate, or K-carrageenan in Pb2+ adsorption, nanocrystalline cellulose/sodium alginate/K-carrageenan composite hydrogel beads were prepared to adsorb Pb(II) from aqueous solutions. The objective of this study was to demonstrate the excellent potential of the composite hydrogel beads for heavy metal ion adsorption. We successfully prepared ecofriendly Fe-modified nanocrystalline cellulose/sodium alginate/K-carrageenan composite hydrogel beads and characterized them. The structure and adsorption mechanism were investigated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, and the optimal adsorption conditions were determined. The tricomponent hydrogel beads were robust and exhibited improved adsorption capacity for Pb2+ and good reusability. The adsorption results could be fitted well with a pseudo-second-order kinetic model and the Langmuir adsorption model. The maximum adsorption capacity obtained by fitting was 351.04 mg g−1. Recycling experiments revealed that the adsorption capacity of the adsorbent remained high after five cycles of reuse.