A new approach for determination of water soluble hexavalent chromium in real cement and industrial water samples using Ni-Fe layered double hydroxides/urea/glycerol nanocomposite based potentiometric sensor

Abstract

Hexavalent chromium (Cr (VI)) is considered one of the most toxic elements that directly affects human health and the environment. Therefore, in this study, two sensitive and selective potentiometric sensors are proposed for Cr (VI) detection in various real cement and industrial water samples based on Ni-Fe layer double hydroxides/urea (Ni-Fe LDH/UA) (sensor I) and Ni-Fe LDH/UA/Glycerol (sensor II) nanocomposites using 1,3-didecyl-2-methylimidazolium-Chromate ion-pair (TEGO-Cr) and cetylpyridinium bromide (CPB). Also, the current study discussed the reducing effect of the alkaline sulfur solution on Cr (VI) and other effects on cement properties. The examined sensors presented excellent Nernstian slopes with short response times (<8 s). The fabricated sensors showed a lower detection limit reached 6.0 × 10−8 mol L−1 (3.0 µg L−1) over a wide pH range (4–9). The proposed potentiometric sensors were successfully performed for Cr (VI) determination in real cement and industrial water samples. The present study presented that sulfur solution can be used conveniently to reduce Cr (VI) in the cement industry without any negative effect on the concrete properties of cement.