Hexavalent chromium dual water remediation and sensing based on hybrid polymer/metal-organic framework composites

The environment contains numerous chemical pollutants from natural processes and human activities, includingpesticides, pharmaceuticals, and industrial chemicals. Specifically, the issue of hexavalent chromium waterpollution, whether from natural or industrial sources, remains a global and unresolved threat. Hence, there is aneed for efficient and prompt monitoring of Cr(VI) concentration in water to determine the potential danger andto facilitate the development of efficient remediation strategies. In this work, the metal-organic framework(MOF) UiO-66-NH2 was immobilized into poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymericmembranes, manufactured in different morphologies, to act as Cr(VI) sorbent to develop a novel portable,easily reactivable, and reusable water filtering and sensing technology. The multifunctional membranesdemonstrated an adsorption capacity of 2.32 mg/L in 300 minutes for plasma electrospun-oriented fiber membraneswith 10 % w/v of MOFs. The most efficient morphology was selected and integrated into a portablesystem for simultaneous detection and adsorption in a short time. It shows approximately 50 % adsorption efficiencyand a colorimetric sensitivity with an excellent determination coefficient R2 of 0.990, even for very lowconcentrations at 0.085 ppm. To the best of our knowledge, this work presents the first system that utilizes multistructuredactive materials for the remediation and monitoring of an aquatic contaminant.