In-situ generated carbon dot modified filter paper for heavy metals removal in water

Abstract

Due to rapid industrialization and consequent heavy metal contamination in environment, there is an urgent need to develop cheap approaches for removal of harmful heavy metals. In this work, a simple cheap efficient paper-based technology has been developed for the removal of heavy metals from aqueous solution. For removal of heavy metals, for the first time one step green synthesis of chitosan carbon dots (CD) is reported here, via in-situ approach directly on paper using thermal assisted process. The functional paper with the embedded chitosan carbon dots (CD) has been characterized with UV–visible spectroscopy, Fourier-transformed infra-red spectroscopy (FT-IR), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The efficiency of the chitosan carbon dots paper (CDP) for the removal of heavy metals such as Cr, Sn and Hg were tested by immersing a carbon dot paper in a heavy metals solutions viz. Cr (0.1 mM), Sn (0.1 mM), and Hg (0.25 mM). It was observed that with this approach, we were able to effectively remove (80–100)% of these metals from solution and at the same time worked better than normal paper as well as normal chitosan coated paper. The mechanistic insight of adsorption is also discussed in the paper. Such paper-based separation system of heavy metals will lead to development of simple, facile, green and cost-effective separation system.