Chloro-phosphate impregnated biochar prepared by co-precipitation for the lead, cadmium and copper synergic scavenging from aqueous solution

Abstract This work evaluated the possibility of lead (Pb2+), cadmium (Cd2+) and copper (Cu2+) ions synergic scavenging by a chloro-phosphate impregnated biochar (CPBC) from aqueous solution. Adsorption experiments displayed that the adsorption capacity of heavy metals by CPBC can be improved better compared with the pristine biochar (BC). The X-ray diffraction (XRD) analysis further demonstrated that the precipitation of Pb5(PO4)3Cl, Cd5(PO4)3Cl and Cu3(PO4)3 might be responsible for Pb2+, Cd2+ and Cu2+ scavenging. The competitive adsorption exhibited that Pb2+, Cd2+ and Cu2+ would compete for the same adsorption sites of CPBC when they coexisted and the adsorption affinity of CPBC was observed in the following order: Pb2+ > Cd2+ > Cu2+. The available phosphorus results suggested that the combination of biochar with phosphate materials can both improve the adsorption performance and reduce the risk of eutrophication by using phosphate materials which can provide a promising application for multiple heavy metals scavenging.