Efficient removal of Pb(II) ions from aqueous solution by modified red mud

Fei Lyu; Sulin Niu; Li Wang; Runqing Liu; Wei Sun; Dongdong He

doi:10.1016/j.jhazmat.2020.124678

Efficient removal of Pb(II) ions from aqueous solution by modified red mud

J Hazard Mater. 2021 Mar 15:406:124678. doi: 10.1016/j.jhazmat.2020.124678. Epub 2020 Nov 26.

Authors

Fei Lyu¹, Sulin Niu², Li Wang¹, Runqing Liu¹, Wei Sun¹, Dongdong He³

Affiliations

¹ School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, Central South University, Changsha 410083, China.
² School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
³ School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, Central South University, Changsha 410083, China. Electronic address: hedongdong@csu.edu.cn.

PMID: 33296756
DOI: 10.1016/j.jhazmat.2020.124678

Abstract

In the work, we employed a hydrothermal method for modification of red mud using colloidal silica and sodium hydroxide under mild conditions, and applied it into adsorbing Pb(II) ions in aqueous solutions. In the modification, zeolite structure was formed. The adsorption experiments found that the adsorption capacity of the modified red mud for Pb(II) ions was significantly improved, almost 10 times as much as that of the original red mud. Both the pseudo-first-order and pseudo-second-order kinetic equation can describe the adsorption process, indicating it a more complicated interaction. Langmuir and Dubinin-Radushkevich models well fit the adsorption isotherm, indicating that the modified red mud mainly removes lead ions from aqueous solution by monolayer physical adsorption. According to the fitting results, the saturated adsorption capacity of Pb (II) by the modified red mud is 551.11 mg/g, confirming its high efficiency adsorption performance. XRD, FTIR, XPS and SEM-EDS all detected the formation of PbCO₃ and Pb₃(CO₃)₂(OH)₂. It was speculated that the adsorption mechanism should be attributed to the joint contribution of ion exchange and precipitation. The excellent performance of the modified red mud on Pb(II) ions adsorption makes it a promising candidate for the treatment of wastewater contaminated by heavy metal ions.

Keywords: Adsorption; Ion exchange; Pb(II) ions; Precipitation; Red mud.

Publication types

Research Support, Non-U.S. Gov't