Synergistic removal of fluoride from groundwater by seed crystals and bacteria based on microbially induced calcium precipitation

Zhao Wang; Junfeng Su; Amjad Ali; Ruijie Zhang; Wenshuo Yang; Liang Xu; Jun Shi; Zhihong Gao

doi:10.1016/j.scitotenv.2021.150341

Synergistic removal of fluoride from groundwater by seed crystals and bacteria based on microbially induced calcium precipitation

Sci Total Environ. 2022 Feb 1;806(Pt 1):150341. doi: 10.1016/j.scitotenv.2021.150341. Epub 2021 Sep 15.

Authors

Zhao Wang¹, Junfeng Su², Amjad Ali¹, Ruijie Zhang¹, Wenshuo Yang¹, Liang Xu¹, Jun Shi¹, Zhihong Gao¹

Affiliations

¹ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
² School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: sjf1977518@sina.com.

PMID: 34563912
DOI: 10.1016/j.scitotenv.2021.150341

Abstract

A new hypothesis that seed crystals (SC) and bacteria based on microbially induced calcium precipitation (MICP) synergistically remove fluoride (F^-) from groundwater was proposed, with a focus on evaluating the defluoridation potential of this method and revealing its F^- removal mechanism. The crucial conditions were optimized to reduce preparation and operation costs. SC furnished more available binding sites due to the existence of bacteria, and the reuse experiments showed that the defluoridation efficiency of SC still remained a high level after 14 cycles (70.10%), with a residual F^- concentration of 0.96 mg L^-1. The SEM-EDS, FTIR and XRD analyses indicated the predominant F^- removal mechanism of SC could be ascribed to the chemisorption, ion exchange, and co-precipitation. Moreover, ion exchange and co-precipitation (PO₄^3- involvement) were validated more contributive than chemisorption (CaCO₃ and CaSO₄ involvement). As a feasible, reusable, and eco-friendly technique, SC suggests promising applications in the treatment of fluoride-contaminated groundwater.

Keywords: Defluoridation; Groundwater; Mechanisms; Pseudomonas WZ39; Seed crystals.

MeSH terms

Bacteria
Calcium
Fluorides*
Groundwater*

Substances

Fluorides
Calcium