Efficient Use of Porous Hybrid Materials in a Selective Detection of Lead(II) from Aqueous Solutions: An Electrochemical Study

Abstract

Due to health and pollution concerns of aquatic environments related to the presence of heavy metal toxic ions, the necessity of developing devices able to detect and to monitor such kinds of species has recently gained importance. Carbon paste electrodes (CPEs) a starting approach to obtain new ion-selective devices by supporting materials like bentonite and/or clay; which become sensitive to lead(II) when they are suitably modified by chemical treatments to obtain different hybrid materials. In this work, two natural clays and three different hybrid materials were produced and then were characterized by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy to assess their physico-chemical properties. After this stage, the electrochemical characterization of the modified CPEs using hybrid materials was performed by cyclic voltammetry, using the standard Fe(CN) 6 4− /Fe(CN) 6 3− redox couple. Subsequently, this study performed electrochemical experiments on lead(II) containing solutions, to test the ability of the examined CPEs to detect this toxic ion present in very low amounts. Lead(II) exhibited a reversible two electron oxidation/reduction behaviour in the cyclic voltammetry analyses and a reasonably good linear behaviour of the current associated with the oxidation peak as a function of its concentration (5.0-40.0 µg/L). The detection limit was found to vary in the range of 3-5 µg/L for the different modified CPEs. The presence of several co-existing ions showed that an interference variation had occurred. These results, therefore, show a restriction of the selectivity of the electrode up to a certain extent in the lead(II) detection. Finally, tap water with spiked lead(II) was analyzed to verify the suitability of the electrodes in the low level detection of lead(II) from real matrix samples.

Sensitive Metal Oxide-Clay Nanocomposite Colorimetric Sensor Development for Aflatoxin Detection in Foods: Corn and Almond

“…26 Gumpu et al 27 reported increased specific reaction and electron transfer rate between the target analyte and metallic nanoparticle-based clay nanocomposite on the electrode surface in aqueous solution. 23 , 28 , 29 Treatment of bentonite with ZnO NPs are in accordance with the study published by Rashid et al, 25 which reports the binding efficiency of bentonite clay increased with ZnO NPs for AFs within biological cells. It is essentially due to Zn ions on the bentonite surface, which creates a AFs-Zn chelation complex at the dicarbonyl functional group of AFs.…”

“…Lately, there are a few colorimetric method-based reports for quantification of macro organic molecules like pollutants and heavy metals , by colorimetric binding with supported metal oxide NPs on clay composites. The detection involved estimating the direct output signal proportional to the interaction caused between the analyte and supported composite material.…”

Environmental Friendliness and High Performance of Multifunctional Tween 80/ZnO-Nanoparticles-Added Water-Based Drilling Fluid: An Experimental Approach

“…Moreover, crystalline characteristics of sepiolite were found at 26 and 35° on 2θ scale corresponded to (371) and (080) planes . Crystalline characteristics of quartz were observed at 26° on a 2θ scale matched to the (101) plane . Additionally, XRD reflections at 10 and 17° corresponded to (010) and (100) crystal planes, respectively, which shows the kaolinite content .…”

“…107 Crystalline characteristics of quartz were observed at 26°on a 2θ scale matched to the (101) plane. 108 Additionally, XRD reflections at 10 and 17°corresponded to (010) and (100) crystal planes, respectively, which shows the kaolinite content. 109 Nonetheless, diffraction patterns of quartz, sepiolite, and kaolinite were not consistent compared to montmorillonite/smectite.…”

Electroreduction of lead(II) ions on lead electrode in the presence of surfactants and different electrolytes

“…In recent years, there has been increased interest in studies on additions of water-soluble polymers with several functional groups having different properties, which provide high adsorption capacity on electrodes and have an appreciable effect on the electrode reactions [7,8]. It has been observed that the presence of surfactants makes it difficult for electrode processes to progress, as it produces an inhibitory effect explained by the blocking of the electrode's surface [9,10].…”