Sequestration of free and chelated Ni(II) by structural Fe(II): Performance and mechanisms

Hongping He; Jiaxin Wang; Xunchang Fei; Deli Wu

doi:10.1016/j.envpol.2021.118374

Sequestration of free and chelated Ni(II) by structural Fe(II): Performance and mechanisms

Environ Pollut. 2022 Jan 1;292(Pt A):118374. doi: 10.1016/j.envpol.2021.118374. Epub 2021 Oct 14.

Authors

Hongping He¹, Jiaxin Wang², Xunchang Fei³, Deli Wu⁴

Affiliations

¹ College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, PR China; State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai, 200092, PR China; School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore.
² College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, PR China.
³ School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Clean Tech One, 637141, Singapore.
⁴ State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control Ecological Security, Shanghai, 200092, PR China. Electronic address: wudeli@tongji.edu.cn.

PMID: 34656684
DOI: 10.1016/j.envpol.2021.118374

Abstract

Ni(II) and chelated Ni(II) in wastewater are of environmental concern. This study explores the sequestration potential of structural Fe(II) in solid phase (≡Fe(II)) on Ni(II) and EDTA-Ni(II) using freshly prepared ferrous hydroxyl complex (FHC) as the Fe(II)-bearing mineral. The 1 mM Ni(II) could be completely sequestrated in 20 min by 3 mM FHC, although the sequestrated Ni(II) was partially released after 20 min. It is calculated that up to 156 mg Ni(II)/g Fe(II) can be sequestrated by ≡Fe(II) under neutral pH and anaerobic condition. According to the characterizations of the solid products, the large surface area for Ni(II) adsorption and the high ≡Fe(II) reduction capacity for Ni(II) reduction are the main contributors to the Ni(II) sequestration. After the reaction, the FHC is transformed to stable Fe-Ni layered double hydroxides. The concomitant ions can be either promotional or inhibitory to the sequestration performance depending on the ion type. The combination of FHC and Fe(III) can effectively sequestrate EDTA-Ni(II), whereas FHC alone has a low efficiency. Fe(III) substitutes Ni(II) from the EDTA-Ni(II), benefiting the subsequent Ni(II) sequestration by ≡Fe(II). This study demonstrates that ≡Fe(II) suspension is an cost-effective option for remediating Ni(II)-containing wastewater.

Keywords: EDTA-Ni(II); Ni(II); Reduction; Sequestration; Structural Fe(II).

MeSH terms

Ferric Compounds*
Ferrous Compounds
Hydroxides
Oxidation-Reduction
Wastewater*

Substances

Ferric Compounds
Ferrous Compounds
Hydroxides
Waste Water