“…A time of 100 s, as pre-concentration time for all measurements were selected. At 100 s, the modified electrodes' sensitivity is similar or better than that reported in the literature with other electrodes after 150 s accumulation times [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], which means that the new electrodes are could save analysis time. Figure 4 Charge versus analyte preconcentration time.…”
The evaluation of glassy carbon (GC) electrodes modified with a Nafion (Nf) film and doped with nanoalloys (Nys) deposits of Ag–Hg and Ag–Bi and their application to determination of Cd (II) and Pb(II) in marine sediments, is described. Deposited Ag–Hg and AgBi Nys have a size of approximately ~80 nm dispersed and embedded inside the booths of the Nf net, while other of them remained on Nf net surface. For the AgBiNysNf-GC electrode, a detection limit (DL), 3 s criterion, slightly higher than for the AgHgNysNf-GC modified electrode was obtained. Accuracy of measurements was asserted by comparison with quantification of Cd and Pb in three sets of marine sediments samples previously analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The values of the standard deviation and the coefficients of variation are very low, and also comparable between the different determinations.
“…A time of 100 s, as pre-concentration time for all measurements were selected. At 100 s, the modified electrodes' sensitivity is similar or better than that reported in the literature with other electrodes after 150 s accumulation times [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], which means that the new electrodes are could save analysis time. Figure 4 Charge versus analyte preconcentration time.…”
The evaluation of glassy carbon (GC) electrodes modified with a Nafion (Nf) film and doped with nanoalloys (Nys) deposits of Ag–Hg and Ag–Bi and their application to determination of Cd (II) and Pb(II) in marine sediments, is described. Deposited Ag–Hg and AgBi Nys have a size of approximately ~80 nm dispersed and embedded inside the booths of the Nf net, while other of them remained on Nf net surface. For the AgBiNysNf-GC electrode, a detection limit (DL), 3 s criterion, slightly higher than for the AgHgNysNf-GC modified electrode was obtained. Accuracy of measurements was asserted by comparison with quantification of Cd and Pb in three sets of marine sediments samples previously analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The values of the standard deviation and the coefficients of variation are very low, and also comparable between the different determinations.
“…A different methodology was employed for in situ measurements by electrochemical detection using SnS-decorated Bi 2 O 3 nanosheets. The composite exhibited high sensitivity and efficient detection for the removal of heavy metals with high toxicity, which limits of detection was 1.50 nM for Cd 2+ and 1.40 nM for Pb 2+ [39]. Quantification of metallic ions is essential during the different steps of the water cycle that goes through various biological processes.…”
Section: Measurement Methods Using Nanostructuresmentioning
A nanostructure is a system in which at least one external dimension is in the nanoscale, it means a length range smaller than 100 nm. Nanostructures can be natural or synthetic and determine the physicochemical properties of bulk materials. Due to their high surface area and surface reactivity, they can be an efficient alternative to remove contaminants from the environment, including heavy metals from water. Heavy metals like mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), and chromium (Cr) are highly poisonous and hazardous to human health due to their non-biodegradability and highly toxic properties, even at trace levels. Thus, efficient, low-cost, and environmentally friendly methodologies of removal are needed. These needs for removal require fast detection, quantification, and remediation to have heavy metal-free water. Nanostructures emerged as a powerful tool capable to detect, quantify, and remove these contaminants. This book chapter summarizes some examples of nanostructures that have been used on the detection, quantification, and remediation of heavy metals in water.
“…Therefore, sensitive detection and effective separation strategies for Cu 2+ in wastewater are urgently needed. Currently, some materials, such as COF, SnS-Bi 2 O 3 and UiO-66-decorated three-dimensional microporous carbon [4][5][6], have been reported for the simultaneous detection and adsorption of HMIs. These materials display high sensitivity and effective removal for HMIs, but their synthesis methods are slightly complicated.…”
Sensitive detection and efficient removal of heavy metal ions with high toxicity and mobility are of great importance for environmental monitoring and control. Although several kinds of functional materials have been reported for this purpose, their preparation processes are complicated. Herein, nitrogen self-doped activated porous biochar (NAC) was synthesized in a facile process via an activation–carbonization strategy from cicada shell rich in chitin, and subsequently employed as an effective functional material for the simultaneous determination and removal of Cu2+ from aqueous media. With its unique porous structure and abundant oxygen-containing functional groups, along with the presence of heteroatoms, NAC exhibits high sensitivity for the electrochemical sensing of Cu2+ in concentrations ranging from 0.001 to 1000 μg·L−1, with a low detection limit of 0.3 ng·L−1. Additionally, NAC presents an excellent removal efficiency of over 78%. The maximum adsorption capacity is estimated at 110.4 mg/g. These excellent performances demonstrate that NAC could serve as an efficient platform for the detection and removal of Cu2+ in real environmental areas.
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