Application of Modified Iron-Based LDH Materials in Geothermal Water Treatment

Geothermal waters are generally enriched in multiple groups of harmful components, which threaten the safety of drinking water for the surrounding residents when non-concentrated discharged in the form of hot springs. In this paper, five iron-based LDH (Fe-LDH) modified materials were prepared and used in the treatment of hot springs in typical geothermal areas of Yunnan. The results show that Fe-LDH has the best removal of arsenic, followed by fluoride and tungsten, and the removal of antimony and boron was influenced by coexisting ions; whereas, the modified materials effectively narrow the gap of competitive sorption between different harmful components, which shows that ion exchange capacity of the lactate intercalated Fe-LDH was significantly improved and the removal of fluorine and boron was enhanced, while the delaminated Fe-LDHs exposed more active sites and increased the interlayer contact, thus it had a greater enhancement on the removal of arsenic and tungsten, which are primarily complexed with iron, along with the removal of fluoride and boron by ion exchange. Finally, the best sorbent in static sorption performance, L-asparagine delaminated Fe-LDH, could dynamically and effectively remove multiple groups of harmful components from hot springs as a filling material for small water treatment devices, which provides a practical method for the remediation of geothermal waters. © 2023 China University of Geosciences. All rights reserved.