Fabrication of cellulose@Mg(OH)2 composite filter via interfacial bonding and its trapping effect for heavy metal ions

Abstract The utilization of renewable biomass cellulose in treating pollution of heavy metal ions (HMIs) is one of overarching and appealing strategies, because it simultaneously satisfies sustainable development and resolves ever-increasing environmental issue. In this regard, the composite cellulose@Mg(OH)2 was prepared via a facile method and explored for its use as water treatment agent. It is demonstrated that the smaller and thinner hexagonal Mg(OH)2 flakes are constructed onto the cellulose substrate by self-assembling; two components are chemically coupled via hydrogen bonds and Mg-Oc (cellulose oxygen) dative bonds; what’s more, the coupling of cellulose with Mg(OH)2 (1 0 1) facet is much more preferential than with (0 0 1) facet. The resultant composite material shows remarkable HMI removal performance: large capacities of 734.9, 595.8 and 1473.1 mg g−1 for Cd2+, Cu2+ and Pb2+, respectively. Further assisted by good shaping property of the cellulose substrate, the composite is capable of being made into filter, which practically separates HMIs and purifies wastewater with high removal efficiency (99.99%) for Cd2+ even after operating for 110 days and potable water can be obtained. The mechanism is delineated with removal models and characterizations of HMI-recovered products.