(101f) Nanorod Metal Organic Framework (MOF) As a Luminescent Probe for Selective Detection of Carcinogenic Hexavalent Chromium in Aqueous Medium

The need for the development of probes for the detection of hexavalent chromium (Cr⁶⁺) is paramount since this form of chromium is a known carcinogen and causes adverse effect to human health. Chemicals toxicity and hazardous impact on our environment has been on the ascendency becoming one of the pollution concerns in the environmental industry. Nanoscale organometallic frameworks have shown successful evidence of detecting and removing hazardous substances from aqueous media.

In this regard, nanorod metal organic framework has been used over the years to selectively detect the existence of hexavalent chromium ions in the form of CrO₄^2- and Cr₂O₇^2- in contaminated aqueous phases. This work presents for the first time the use of metal precursors in the form of zinc acetate dihydrate and various types of pyridinecarboxaldehydes in combination with trimesic acid to form a luminescent probe with sufficient functional sensitivity to detect hexavalent chromium ions from other metal ions. With electrostatic force of attraction between the zeolitic framework and the chromate anions, this work reveals the essential mechanism that the nanorods employed as a luminescent probe. The probe showed low detection limits comparable to already reported hexavalent chromium fluorescent-MOF probes.

Results reveal that the nanorod zeolitic framework could serve as a good luminescent sensor for CrO₄^2- and Cr₂O₇^2- in contaminated aqueous phase.