Atom-level local structures of a ternary composite of cellulose and metal (hydro)oxides and its applications on lead ion capture

Discharging of lead-contained sewage has posed great threats to the ecological environment and human being health. To effectively eliminate Pb²⁺, a ternary composite cellulose/zinc oxide/magnesium hydroxide (labelled as CelZnMg) was prepared by a simple hydrothermal method. The XRD, SEM, TEM and XPS were applied to analyze CelZnMg. It shows that ZnO particles and Mg(OH)₂ sheet uniformly distribute on the surface of cellulose. Comprehensive density functional theory calculations realize that the composite has four structural arrangements at the atomic level. Its three components are chemically coupled, which in return stabilize the whole composite. Computationally and experimentally, CelZnMg can separate Pb²⁺ ions from water and immobilize them on the composite surface, where the removal efficiency reaches 99.7 %. The removal mechanism has been proposed.