Metal–Organic Frameworks: Opportunities and Challenges in Nutrient Recovery

Abstract

Nutrient recovery from waste streams is a critical strategy for promoting sustainable agriculture and mitigating environmental degradation. Essential nutrients commonly present in organic waste and wastewater, such as nitrogen and phosphorus, can be reclaimed and reintegrated into agricultural systems. Metal‒organic frameworks (MOFs), which are composed of metal clusters coordinated with organic ligands, have emerged as promising materials for adsorption and have the potential for nutrient recovery and pollutant removal because of their high porosity, large surface area, and tunable physicochemical properties. These attributes enable MOFs to serve in diverse applications, including heavy metal adsorption, organic pollutant degradation, and nutrient transformations. This review provides a comprehensive overview of MOF synthesis methods—including solvothermal, microwave-assisted, mechanochemical, electrochemical, and sonochemical techniques—and highlights their structural properties and adsorption mechanisms. The applications of MOFs are then discussed, with a particular emphasis on their potential for environmental conta-minant removal and agricultural integration. To date, MOFs have demonstrated potential for reducing heavy metals through adsorption, enhancing organic degradation, and promoting nutrient mineralization. However, challenges in their application in agriculture remain. This review also examines the cytotoxicity, organ-specific toxicity, and phytotoxicity of MOFs to assess their environmental and health safety. Their integration into agricultural systems, including soilless agriculture, where liquid organic and inorganic fertilizers are used, is discussed from several perspectives. Overall, this paper reviews the potential of MOFs as multifunctional materials for environmental remediation and sustainable nutrient recovery in agriculture while highlighting the need for further research to ensure their safe and effective application.