Waste capacitor: A fresh approach to detect and remove Cr(VI) from water and making it an energy harvesting material

Abstract

The large scale amplification of industrial discharge in the modern era is resulting in widespread water pollution, especially from various industrial effluents and wastewater containing heavy metals, posing a severe threat to our environment. In order to combat such problems, this work aims on Multifunctional Fluorescent Nano-Sensor (MFNS) mediated simultaneous detection and removal of hexavalent chromium from real life wastewater which further converts it into an energy harvesting material, namely, “Waste capacitor”. This smart material can detect the presence of the targeted heavy metal (Cr(VI)) in the wastewater and can entrap it by using a facile adsorption process. Thereafter, it will change its microstructure which further enhances its dielectric properties. Morphology, microstructure and optical properties of the synthesized material have been studied thoroughly and a turn-off based fluorescence sensing has been reported herein. Photoinduced electron transfer (PET) based fluorescence quenching is mainly responsible for this sensing mechanism. The selectivity and sensitivity of the material during fluorescence sensing have also been studied by using standard Stern-Volmer method showing that the synthesized material is tremendously selective and sensitive towards the specific target ion. High surface area with slit-like porous structure enhances the adsorption based removal of the contaminant. Nearly 76% of contaminants have been removed by using this smart material. After adsorbing specified target, this MFNS changes its microstructure and results in superior dielectric constant with a minimal tangent loss. Tremendous sensitivity (in nM range), selectivity towards the specific contaminant and adsorption of toxic heavy metal and converting it into a green energy harvesting material (waste capacitor) makes this smart multifunctional material a real waste to wealth converter.