Successive removal of Pb2+ and Congo red by magnetic phosphate nanocomposites from aqueous solution

Fan Zhang; Xiaoxiu Tang; Jing Lan; Yuxiong Huang

doi:10.1016/j.scitotenv.2018.12.291

Successive removal of Pb²⁺ and Congo red by magnetic phosphate nanocomposites from aqueous solution

Sci Total Environ. 2019 Mar 25:658:1139-1149. doi: 10.1016/j.scitotenv.2018.12.291. Epub 2018 Dec 20.

Authors

Fan Zhang¹, Xiaoxiu Tang², Jing Lan³, Yuxiong Huang⁴

Affiliations

¹ College of Science, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: zhangfan0128@njau.edu.cn.
² College of Science, Nanjing Agricultural University, Nanjing 210095, China.
³ College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China.
⁴ Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, China; Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106, USA.

PMID: 30677978
DOI: 10.1016/j.scitotenv.2018.12.291

Abstract

The successive removal of Pb²⁺ and Congo red (CR) from aqueous solution by three magnetic phosphate nanocomposites (Fe₃O₄@Sr₅(PO₄)₃(OH), Fe₃O₄@Ba₃(PO₄)₂, and Fe₃O₄@Sr_5xBa_3x(PO₄)₃(OH), denominated FSP, FBP, and FSBP, respectively) was systematically investigated in comparison with Fe₃O₄ (denominated F) nanoparticle. FSP, FSBP, F, and FBP exhibited a high removal capacity of 351, 272, 76, and 23 mg/g for Pb²⁺, respectively. These materials could be reclaimed by magnetic separation and then used for successive CR remediation, showing a high CR removal capacity of 224, 163, 126, and 61 mg/g, respectively. The isothermal and kinetic behavior fitted well with the Langmuir model and pseudo-second-order model, respectively. The successive removal mechanism by these magnetic phosphates was proposed to be the ion exchange between Pb²⁺ and Sr²⁺ in the lattice and then the loaded Pb²⁺ could contact with anionic dye CR to form precipitation on the surface of materials, inhibiting the leaching of Pb²⁺ ions from the reclaimed materials back into water. In addition, these materials showed good reusability and practical application. This study demonstrated the potential of these low cost phosphate nanocomposites as promising materials for successive removal of Pb²⁺ and CR from water.

Keywords: Dye; Heavy metal; Magnetic phosphate nanocomposites; Successive removal; Water treatment.