Adsorption properties and mechanism of Pb2+, Cu2+ and Zn2+ by iron base zeolite-like geopolymer derived from copper slag

Copper slag-based magnetic zeolite-like geopolymer (F3O4@GM) was prepared using copper slag as raw material, NaOH and industrial sodium silicate as alkaline activator, and then used for the removal of heavy metal ions Pb2+, Cu2+ and Zn2+. The effects of initial pH of solution, dosage and initial mass concentration of adsorbent on the adsorption performance were investigated, followed by analysis on the adsorption kinetics, adsorption isotherm and thermodynamics. Moreover, the adsorption mechanism was explored by XRD, FTIR, SEM, BET and XPS. The results showed that the adsorption behavior of F3O4@GM for Pb2+, Cu2+, Zn2+ followed the Langmuir model with the corresponding maximum theoretical adsorption capacities of 555, 489 and 125 mg/g, respectively, while the adsorption process fitted the pseudo-second-order kinetic model. The excellent adsorption performance of F3O4@GM was attributed to its large specific surface area. The adsorption mechanisms were associated with ion exchange, electrostatic attraction, surface complexation and pore sedimentation. F3O4@GM can be used as an eco-friendly, desirable and economic adsorbent in the treatment of heavy metal polluted water, providing a cheap and convenient choice for the treatment of heavy metals pollution while realizing the recycling and harmless treatment of copper slag. © 2023 Fine Chemicals. All rights reserved.