Natural fluorapatite dissolution kinetics and Mn2+ and Cr3+ metal removal from sulfate fluids at 35 °C

Vandeginste, Veerle; Cowan, Charlotte; Gomes, Rachel L.; Hassan, Tharwat; Titman, Jeremy

Abstract

In light of the consequences of global warming and population growth, access to safe drinking water becomes an ever greater challenge, in particular in low to middle income countries in arid regions. Moreover, mining which may cause acid mine drainage and heavy metal contamination puts further pressure on management of limited water resources. Hence, the development of cost effective water treatment methods is critical. Here, using batch reactor experiments we investigate the kinetics and mechanisms behind divalent Mn and trivalent Cr removal from sulfate fluids using natural fluorapatite at 35 °C. The results show that the fluorapatite dissolution rate depends on fluid pH, and that dissolution is the dominant mechanism in fluids with pH below 4. Apatite can thus serve as remediation to neutralize acidic fluids. Fluid pH of 4–6 triggers a dissolution-precipitation mechanism, in some cases following upon a dissolution-only period, with the formation of a metal phosphate. In these experiments, Cr removal is two to ten times faster than Mn removal given similar solution pH. The results demonstrate that natural apatite represents a promising, cost effective material for use in passive remediation of mining-induced contamination of soils and groundwater in arid regions.

Citation

Vandeginste, V., Cowan, C., Gomes, R. L., Hassan, T., & Titman, J. (2020). Natural fluorapatite dissolution kinetics and Mn2+ and Cr3+ metal removal from sulfate fluids at 35 °C. Journal of Hazardous Materials, 389, Article 122150. https://doi.org/10.1016/j.jhazmat.2020.122150

• Journal Article Type: Article
• Acceptance Date: Jan 20, 2020
• Online Publication Date: Jan 20, 2020
• Publication Date: May 5, 2020
• Deposit Date: Jan 23, 2020
• Publicly Available Date: Jan 20, 2020
• Journal: Journal of Hazardous Materials
• Print ISSN: 0304-3894
• Electronic ISSN: 1873-3336
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 389
• Article Number: 122150
• DOI: https://doi.org/10.1016/j.jhazmat.2020.122150
• Keywords: Environmental Engineering; Waste Management and Disposal; Pollution; Health, Toxicology and Mutagenesis; Environmental Chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/3785939
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0304389420301382