Colorimetric Sensors Based on the Metal-Organic Frameworks for Highly Sensitive and Rapid Detection of Cr(VI)

Abstract

Cr(VI), a hazardous and cancer-causing metal ion that is typically released into wastewater as a result of various production processes, has a negative impact on both human health and the environment. In order to prevent industrial sewage from entering the water supply, Cr(VI) must be captured and removed. For detecting Cr(VI), there are few efficient colorimetric techniques. Here, we created a straightforward and practical technique based on the Cu metalorganic framework (Cu-MOF) to construct a visual colorimetric sensor and UV-vis spectrum quantitative analysis method for Cr(VI). In the presence of Cu-MOF, the colorless 3, 3′, 5, 5′-tetramethylbenzidine solution can be quickly transformed into the deep blue colored oxTMB without H2O2. Within 1 minute, this technique can detect Cr(VI) with a broad linear range of 0.2-100 μM. It was established that the limits of detection were 0.023 μM. It exhibits good selectivity towards potentially disruptive metal ions and anions in wastewater. Cu-MOF’s sensitivity and rapid response time are highly helpful for the colorimetric detection of Cr(VI), which offers great promise for the rapid detection of environmental samples.

Keywords: Cu-MOF nanozyme, Cr(VI), colorimetric sensor, real samples