Abstract:
Heavy metal ions are considered as potential environmental pollutant as many of them are high
capability of biomolecules toxicity even at low concentration. Lead (Pb) is one of the major heavy
metal pollutants that can cause severe health problems to human and the environment. This
indicate that its concentration should be known to learn its levels in various environmental
systems, and a powerful and economical analytical technique should be there to do the same. In
this study we report a, simple, rapid, cost effective and environmentally friendly AgNPs-based
nano-sensor synthesized in line with green chemistry principles by using Parthenium
hysterophorus leaf extract. The AgNPs was synthesized by mixing 100 mL of 8 mM AgNO3 solution
with 3 mL of plant extract solution in a 250 mL Erlenmeyer flask with continuous shaking in a
dark room. The AgNPs formation was confirmed by change in color of the solution from light
yellow to reddish brown within 15 minutes and formation of absorption band at 432 nm on UV vis spectra. The biosynthesized AgNPs were characterized by UV-vis spectroscopy, Fourier
transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy,
and energy dispersive x-ray spectroscopy techniques. The biosynthesized AgNPs was used to
develop colorimetric sensor for Pb2+ detection. The developed AgNPs-based colorimetric sensor
was sensitive and selective toward Pb2+ with the limit of detections of 2.8 and 0.12 µM by visual
and UV-vis detection techniques, respectively. The method also exhibited excellent linearity (R2 =
0.9959) within 0.5 to 100 µM concentration range and precision (intra-day and inter-day %RSD
values were 2.78% and 3.40%, respectively). The practical application of the developed AgNPs based sensor was investigated for colorimetric detection of Pb2+ in various real world water
samples such as wastewater effluents, leakage, fresh water, tap water and soft drink. The percent
recovery of tested samples was ranged from 99.5–108% indicating the potential applicability of
the technique. Therefore, the developed colorimetric sensor is applicable and recommended for
the detection of Pb2+ ions in various water samples
