Treatment of heavy metal ions-polluted water into drinkable water: Capture and recovery of Pb2+ by cellulose@CaCO3 bio-composite filter via spatial confinement effect

A bio-composite of cellulose@CaCO 3 (Cel@CaCO 3 ) has been prepared via a facile precipitation reaction route, in anticipation of solving the toxic lead ion pollution problem and satisfying the sustainable development. The microstructures along with the morphology were characterized by XRD, FT-IR, SEM and TEM. It is found that CaCO 3 forms the hydrogen bonding with cellulose in the composite, which makes it cover on the cellulose fibers. This would construct a suitable micro-environment for the Pb 2+ capture and removal due to the spatial confinement effect. The high performance has been achieved with the up-taken capacity of 602.3 mg·g −1 . When treating the wastewater with the Pb 2+ concentration less than 50 mg·g −1 , almost 100 % removal rate was obtained only within 10 min. The Pb 2+ ions were trapped on the surface of cellulose and appeared as the form of PbCO 3 . Consequently, the complete separation and recovery would be accomplishable without the secondary pollution, for the spent bio-composite filter was removed easily and conveniently. Notably, the treated water met the drinkable criterion. The roles of cellulose and removal mechanism have also been explained in details.