Iron‐based metal–organic frameworks for rapid and effective phosphorus removal from eutrophic lake water

Abstract

Efficient removal of phosphorus from water is an effective means to control lake eutrophication. Two kinds of efficient metal–organic frameworks (MOFs), MIL‐53(Fe) and MIL‐100(Fe), were prepared. These MIL MOFs were used to remove phosphorus from eutrophication lake water. The factors affecting phosphorus adsorption were systematically studied, including adsorption time, adsorption dose, and coexisting ions. The two adsorbents exhibited excellent phosphorus adsorption performance. Within 30 min after adsorption, the phosphorus concentration decreased rapidly from the initial 0.60 to 0.083 mg·L−1 for MIL‐53(Fe) and 0.052 mg·L−1 for MIL‐100(Fe). The maximum capture capacity of MIL‐100(Fe) is 106.99 mg·P·g−1, while the maximum capture capacity of MIL‐53(Fe) is 103.17 mg·P·g−1. In addition, iron‐based MOFs also show superior selectivity to phosphate compared with other anions (including nitrate, sulfate, bicarbonate, and carbonate). After adsorption, both adsorbents can be effectively regenerated using NaCl solution, and both materials can be reused four times. After a series of characterization, it was found that the main mechanism for phosphorus adsorption is electrostatic interaction and coordination. Specifically, these two materials can efficiently and rapidly adsorb phosphorus in eutrophic water and exhibit superior removal efficiency. This shows that MIL‐100(Fe) and MIL‐53(Fe) have great application potential in removing excess phosphorus.