A research team led by Prof. KONG Lingtao from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has developed a new metal–organic framework (MOF)-based material that can efficiently remove fluoride ions from water and provide real-time visual detection.

This breakthrough addresses key limitations of conventional defluoridation methods, which often suffer from low efficiency and separate processes for removal and monitoring.

The results were published in Separation and Purification Technology and Chemical Engineering Journal.

Fluoride ions are a common water pollutant. While moderate levels are beneficial to human health, excessive fluoride can cause dental and skeletal fluorosis, posing risks to people and ecosystems. Due to their high surface area, tunable porosity, and unique optical properties, MOFs have emerged as promising materials for water purification.

To enhance fluoride removal, the researchers regulated the surface structure of MOFs using interfacial water, creating materials with optimized crystal facets that significantly improve adsorption.

The researchers also developed an integrated dual-metal MOF that can capture fluoride ions and emit a visible fluorescence signal simultaneously. Based on this material, they constructed a visual defluorination device that enables real-time monitoring and efficient fluoride removal.

These studies advance our understanding of MOF design and functionalization and promote the application of MOF-based materials in practical water treatment, offering new solutions for remediating fluoride-contaminated water.

Fig. 1. Surface-specific adsorption of fluoride on the (100) and (101) crystal facets of MIL-88 A(Fe) regulated by interface water. (Image by HE Junyong)

Fig. 2. Visual removal of fluoride ions by La₁/Fe₂-MOFs-NH₂. (Image by HE Junyong)