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ARTICLE

Optimization of Preparation of Fe₃O₄-L by Chemical Co-Precipitation and Its Adsorption of Heavy Metal Ions

Junzhen Di, Xueying Sun^*, Siyi Zhang, Yanrong Dong, Bofu Yuan

College of Civil Engineering, Liaoning Technical University, Fuxin, 123000, China

* Corresponding Author: Xueying Sun. Email:

(This article belongs to the Special Issue: Porous Materials for Sustainable Development)

Journal of Renewable Materials 2023, 11(5), 2209-2232. https://doi.org/10.32604/jrm.2023.025241

Received 30 June 2022; Accepted 16 August 2022; Issue published 13 February 2023

Abstract

To address the serious pollution of heavy metals in AMD, the difficulty and the high cost of treatment, Fe₃O₄-L was prepared by the chemical co-precipitation method. Based on the single-factor and RSM, the effects of particle size, total Fe concentration, the molar ratio of Fe²⁺ to Fe³⁺ and water bath temperature on the removal of AMD by Fe₃O₄-L prepared by chemical co-precipitation method were analyzed. Static adsorption experiments were conducted on Cu²⁺, Zn²⁺ and Pb²⁺ using Fe₃O₄-L prepared under optimal conditions as adsorbents. The adsorption properties and mechanisms were analyzed by combining SEM-EDS, XRD and FTIR for characterization. The study showed that the effects of particle size, total Fe concentration and the molar ratio of Fe²⁺ to Fe³⁺ are larger. Obtained by response surface optimization analysis, the optimum conditions for the preparation of Fe₃O₄-L were a particle size of 250 mesh, a total Fe concentration of 0.5 mol/L, and a molar ratio of Fe²⁺ to Fe³⁺ of 1:2. Under these conditions, the removal rates of Cu²⁺, Zn²⁺, and Pb²⁺ were 94.52%, 88.49%, and 96.69% respectively. The adsorption of Cu²⁺, Zn²⁺ and Pb²⁺ by Fe₃O₄-L prepared under optimal conditions reached equilibrium at 180 min, with removal rates of 99.99%, 85.27%, and 97.48%, respectively. The adsorption reaction of Fe₃O₄-L for Cu²⁺ and Zn²⁺ is endothermic, while that for Pb²⁺ is exothermic. Fe₃O₄-L can still maintain a high adsorption capacity after five cycles of adsorption-desorption experiments. Cu²⁺, Zn²⁺ and Pb²⁺ mainly exist as CuFe₂O₄, Zn(OH)₂, ZnFe₂O₄ and PbS after being adsorbed by Fe₃O₄-L, which is the result of the combination of physical diffusion, ion exchange and surface complexation reaction.

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