Efficient capture of organic dyes and crystallographic snapshots by a highly crystalline amino acid-derived metal-organic framework

The residual presence of organic dyes in water resources or wastewater treatment systems, derived mainly from dumping of different industries, constitutes a major environmental problem with no easy answer. Here we report an eco-friendly water-stable metal-organic framework -prepared from a derivative of the natural amino acid L-serine- featuring functional channels densely decorated with the highly flexible L-serine residues containing hydroxyl groups. The presence of such flexible and functional environment within the confined state of the MOF, leads to a very efficient removal from water of different organic dyes: The cationic Pyronin Y, Auramine O and Methylene Blue and the neutral Brilliant Green, as unveiled by the unprecedented snapshots offered by single crystal X-ray diffraction. This MOF enables highly efficient water remediation, being capable to capture more than 90% of dye content, even at very low concentrations such as 10 ppm, which is similar to that usually found in industrial wastewaters. Remarkably, the removal efficiency is improved in simulated contaminated mineral water with multiple dyes.