Cationic Waste Cotton Fabric for the Adsorptive Colorimetric Detection of Chromium Ion Traces

Abstract

Hexavalent chromium (Cr(VI)) exists in water as carcinogenic anionic species. Here, waste cotton fabric (WCF) was recycled and given a second life as a support for Cr(VI) colorimetric detection. WCF was prepared by grafting 2,3-epoxypropyltrimethylammonium chloride on its surface to make it cationic (cWCF) and suitable for Cr anion adsorption via electrostatic interactions. Two strategies were assessed for Cr(VI) detection in water. In the first method, cWCF was functionalized with color-developing 1,5-diphenylcarbazide (DPC), and the resulting strip was evaluated for Cr(VI) quantification. This sensor exhibited a short response time of 30 s with a limit of detection (LOD) of 0.029 mg/L. In the second method, Cr(VI)-containing samples were initially preconcentrated by adsorption on the cWCF substrate, and then, DPC was added for color development. With this system, the LOD was excellent at 0.0013 mg/L, but the response time was longer at 5 min. Another advantage of the robust cWCF support is that it could be washed and reused multiple times for Cr(VI) detection. The two approaches described here are inexpensive and can be selected for different purposes depending on the sensitivity required as well as the volume of samples and time available to complete the Cr ion assay.

Imidazolium-Functionalized Conjugated Polymer for On-Site Visual and Ultrasensitive Detection of Toxic Hexavalent Chromium

“…With the increasing pace of industrialization and urbanization, heavy metal pollution is growing in an alarming rate, raising severe health concerns across the globe. , Among different heavy metals, chromium (Cr) is a well-known environmental contaminant that is widely employed in a variety of industries such as electroplating, metallurgy, textiles, leather, and so on . Nearly 170,000 tons of Cr is reportedly released into the environment annually by global industrial and production operations .…”

“…Atomic absorption spectrometry (AAS), inductively coupled plasma–mass spectrometry (ICP–MS), ion-selective electrode (ISE) potentiometry, and UV–visible spectrophotometry (UV–vis) are some popular conventional methods for the detection of Cr­(VI). − Unfortunately, such methods are user-hostile in nature due to complicated pretreatment procedures, tedious operations, and sophisticated instrumentation. , Besides, they are inadequate for real-time estimation of Cr­(VI) at remote areas or desirable locations . Fluorescence spectroscopy, on the other hand, has emerged as a very powerful technique for the prompt and sensitive detection of analytes based on the changes in fluorescence signals. − To date, a series of fluorescent sensors based on various materials including quantum dots, − metal–organic frameworks, , metal nanoclusters, − organic small molecules, − etc., have been designed, synthesized, and applied for monitoring Cr­(VI).…”