Construction of a highly stable lanthanide metal-organic framework for effective detection of aryl-organophosphorus flame retardants in simulated wastewater and fruit juices

Abstract

Three isostructural 3D lanthanide metal-organic frameworks, [Ln2(L)2(μ3-OH)2]·2H2O (Ln = Gd (1), Eu (2). Tb (3); H2L = 2,4-pyridinedicarboxylic acid) were synthesized by solvothermal reactions. Compounds 1–3 are constituted by rod-shaped inorganic building units {Ln2(μ3-OH)2}n, which are assembled by the ligands to form 3D channel-type frameworks. Compound 3 exhibits high thermal stability and outstanding chemical resistance in various refluxing organic solvents and boiling aqueous solutions of pH = 2 and 12. Significantly, 3 can be utilized for the first time to detect CDP (cresyl diphenyl phosphate) and TPP (triphenyl phosphate) in wastewater with high sensitivities, low detection limits and good recyclability. This sensing system possesses excellent anti-interference ability toward pH and other retardants, allowing steady sensing of CDP and TPP in real samples such as fresh fruit juices over a broad pH range.