Dual-functionalized strontium phosphate hybrid nanopowder for effective removal of Pb^2 + and malachite green from aqueous solution

Hybrid strontium phosphate nanopowder (called SP for short) were prepared by a one-pot hydrothermal method and characterized by SEM, EDS, TEM, and XRD. The dual removal of Pb^2 + and malachite green (MG) by SP from aqueous solution was systematically investigated. Experiments were carried out in a batch system to optimize operation variables such as solution pH, temperature, adsorbent dosage, and contact time. The adsorption capacity of SP was 829 mg g^− 1 and 763 mg g^− 1 for Pb^2 + and MG (C₀ = 1000 mg L^− 1, at pH 3.5, 45 °C, reaction time of 2 h), respectively. Moreover, SP could be reused for five cycles with a minimal loss of capability (20–30%). Interaction mechanisms were proposed to be ion exchange between Pb^2 + and Sr^2 + in the lattice and the hydrogen bonds between PO₄^3 − in hybrid Pb/Sr-contained phosphate and positively charged hydrogen in MG. This study indicated that SP nanopowder could be facilely produced at a low price and potentially be used as an effective material for removal of both Pb^2 + and MG in aqueous solution.