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

Abstract

The environment contains numerous chemical pollutants from natural processes and human activities, including pesticides, pharmaceuticals, and industrial chemicals. Specifically, the issue of hexavalent chromium water pollution, whether from natural or industrial sources, remains a global and unresolved threat. Hence, there is a need for efficient and prompt monitoring of Cr(VI) concentration in water to determine the potential danger and to 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) polymeric membranes, 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 membranes demonstrated an adsorption capacity of 2.32 mg/L in 300 minutes for plasma electrospun-oriented fiber membranes with 10 % w/v of MOFs. The most efficient morphology was selected and integrated into a portable system for simultaneous detection and adsorption in a short time. It shows approximately 50 % adsorption efficiency and a colorimetric sensitivity with an excellent determination coefficient R2 of 0.990, even for very low concentrations at 0.085 ppm. To the best of our knowledge, this work presents the first system that utilizes multi-structured active materials for the remediation and monitoring of an aquatic contaminant.