Dual Colorimetric Sensor for Hg2+/Pb2+ and an Efficient Catalyst Based on Silver Nanoparticles Mediating by the Root Extract of Bistorta amplexicaulis

Abstract

Environmental pollution derivated from toxic metals and organic toxins is becoming a serious issue worldwide because of their harmful effects on the ecosystem and human health. Here we are reporting an extremely selective and cost-effective colorimetric sensor for simultaneous recognition of Hg 2+ and Pb 2+ by using green synthesized silver nanoparticles (AgNPs) mediated from the environmental friendly roots extract of Bistorta amplexicaulis. Biogenic synthesized AgNPs were well-characterized by various spectroscopic techniques e.g., UV-vis, FT-IR, XRD, AFM, and Zetasizer. The photophysical potential of synthesized AgNPs toward common metal cations was explored via absorption spectroscopy and colorimetric assay. The hypsochromic shift in the SPR band of AgNPs can easily be detected through naked eyes vision from dark brown to light yellow in the case of Hg 2+. A substantial reduction in the absorbance of AgNPs was recorded upon mixing with Pb 2+. AgNPs based colorimetric sensor is highly sensitive toward Hg 2+ and Pb 2+ with a limit of detection (LOD) of 8.0 × 10 −7 M and 2.0 × 10 −7 M for Hg 2+ and Pb 2+ , respectively. Furthermore, AgNPs showed promising catalytic activity for the degradation of methyl orange dye. These results demonstrate that Bistorta amplexicaulis stabilized silver nanoparticles have potential applications as a colorimetric sensor and an effective catalyst for the degradation of methyl orange.

Optimization, Characterization, and Biological Applications of Silver Nanoparticles Synthesized Using Essential Oil of Aerial Part of Laggera tomentosa

“…2 × 10 −3 M AgNO 3 solution was obtained as optimum concentration with the maximum absorbance peak intensity in the UV-Vis region of AgNPs (Figure 3b). The absence of UV-Vis peaks at higher concentrations of AgNO 3 solution (8 × 10 −3 M and 9 × 10 −3 M) may be due to the excess concentration accelerating the aggregation of AgNPs [43]. The reactants used for AgNPs synthesis were AgNO3 and LTEO solutions.…”

Silver Nanoparticles as a selective probe for Mercury Ions: A Review

“…Because of its distinctive properties, such as particular optical characteristics in the visible spectrum, AgNPs have sparked a lot of interest in the field of colorimetric sensors. AgNPs, in particular, are particularly advantageous due to their inexpensive cost and a 100-fold increase in SPR of the absorption band compared to AuNPs of the same size [51,52].…”

“…The targeted analyte with highly selective detection in presence of another similar ion is an essential characteristic of a sensor behavior to use in analytical fields and it's a major aspect for a colorimetric sensor [51,59]. Some researchers synthesized AgNPs using starch as stabilizing agent to form a yellowish color and gradually became colorless with elevating of mercury ions (II) [60].…”

Gold and Silver Nanoparticle-Based Colorimetric Sensors: New Trends and Applications

“…The color change of AgNPs from dark-brown to light yellow for Hg 2+ and to light brown for Pb 2+ is due to the complexation and aggregation of AgNPs in solution. Thus, this colorimetric sensor offers qualitative and quantitative information simply by naked-eye detection, without using expensive instruments; moreover, it is very sensitive for Pb 2+ and Hg 2+ , presenting a detection limit of 0.2 µM and 0.8 µM for Pb 2+ and Hg 2+ , respectively [76].…”