Electrochemical detection and removal of lead in water using poly(propylene imine) modified re-compressed exfoliated graphite electrodes

Ndlovu, Thabile; Arotiba, Omotayo A.; Sampath, S.; Krause, Rui W. M.; Mamba, Bhekie B.

doi:10.1007/s10800-011-0360-6

Cited by 36 publications

(15 citation statements)

References 32 publications

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“…An EG compact modified with a poly(propylene imine) dendrimer by electrodeposition provides an electrochemical sensor for lead in water [69]. An unmodified EG compact under an applied potential provides the removal of lead ions from water [69].…”

Section: Adsorption and Filtration Behaviormentioning

confidence: 99%

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A review of exfoliated graphite

2015

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Exfoliated graphite (EG) refers to graphite that has a degree of separation of a substantial portion of the carbon layers in the graphite. Graphite nanoplatelet (GNP) is commonly prepared by mechanical agitation of EG. The EG exhibits clinginess, due to its cellular structure, but GNP does not. The clinginess allows the formation of EG compacts and flexible graphite sheet without a binder. The exfoliation typically involves intercalation, followed by heating. Upon heating, the intercalate vaporizes and/or decomposes into smaller molecules, thus causing expansion and cell formation. The sliding of the carbon layers relative to one another enables the cell wall to stretch. The exfoliation process is accompanied by intercalate desorption, so that only a small portion of the intercalate remains after exfoliation. The most widely used intercalate is sulfuric acid. The higher concentration of residue in unwashed EG causes the relative dielectric constant (50 Hz) of the EG to be 360 (higher than 120 for KOH-activated GNP), compared to the value of 38 for the water-washed case. An EG compact is obtained by the compression of EG at a pressure lower than that used for the fabrication of flexible graphite. Compared to flexible graphite, EG compacts are mechanically weak, but they exhibit viscous character, outof-plane electrical/thermal conductivity and liquid permeability. The viscous character (flexural loss tangent up to 35 for the solid part of the compact) stems from the sliding of the carbon layers relative to one another, with the ease of the sliding enhanced by the exfoliation process.

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Section: Adsorption and Filtration Behaviormentioning

confidence: 99%

“…An unmodified EG compact under an applied potential provides the removal of lead ions from water [69].…”

Section: Adsorption and Filtration Behaviormentioning

confidence: 99%

A review of exfoliated graphite

2015

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“…NG flakes (approximately 300 µm particle size) were intercalated with a mixture of concentrated nitric acid and sulfuric acid in a volume ratio of 1:3 for 24 h at room temperature to form a graphite-intercalated compound (GIC) [43]. The intercalated material was washed several times with deionized water until a pH of 6.5 was attained; after this, it was subjected to thermal shock at 800 °C for half a minute so as to force the intercalated material out of the graphite lattice, thus rupturing the layers.…”

Section: Methodsmentioning

confidence: 99%

An Exfoliated Graphite-Based Electrochemical Immunosensor on a Dendrimer/Carbon Nanodot Platform for the Detection of Carcinoembryonic Antigen Cancer Biomarker

2019

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An electrochemical immunosensor for the quantification of carcinoembryonic antigen (CEA) using a nanocomposite of polypropylene imine dendrimer (PPI) and carbon nanodots (CNDTs) on an exfoliated graphite electrode (EG) is reported. The carbon nanodots were prepared by pyrolysis of oats. The nanocomposites (PPI and CNDTs) were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The proposed immunosensor was prepared on an exfoliated graphite electrode sequentially by drop coating CNDTs, the electrodeposition of G2-PPI (generation 2 poly (propylene imine) dendrimer), the immobilization of anti-CEA on the modified electrode for 80 min at 35 °C, and dropping of bovine serum albumin (BSA) to minimize non-specific binding sites. Cyclic voltammetry was used to characterize each stage of the fabrication of the immunosensor. The proposed immunosensor detected CEA within a concentration range of 0.005 to 300 ng/mL with a detection limit of 0.00145 ng/mL by using differential pulse voltammetry (DPV). The immunosensor displayed good stability and was also selective in the presence of some interference species such as ascorbic acid, glucose, alpha-fetoprotein, prostate-specific antigen and human immunoglobulin. Furthermore, the fabricated immunosensor was applied in the quantification of CEA in a human serum sample, indicating its potential for real sample analysis.

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“…SPEs were modified with PPI by electrodeposition, since the PPI improves the electrochemical performances of the sensors [37] as well as enhances the sensitivity toward metal detection [37,40]. Ten cycles of cyclic voltammetry were performed in order to obtain a satisfactory deposition of the dendrimer over the surface of the working electrode (Figure 2A).…”

Section: Poly(propylene Imine) Electrodepositionmentioning

confidence: 99%

A Poly(Propylene Imine) Dendrimer and Carbon Black Modified Flexible Screen Printed Electrochemical Sensor for Lead and Cadmium Co‐detection

et al. 2020

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Towards the development of miniaturised and low-cost sensors for heavy metals detection in water, herein we describe an electrochemical sensor for the codetection of lead and cadmium. The sensor was developed using screen-printed electrode modified with a composite of poly(propylene imine) dendrimer and carbon black. The electrode was modified by drop casting of the carbon black and electrodeposition of the poly(propylene imine) dendrimer. This modified electrode (sensor) was characterised by cyclic voltammetry and electrochemical impedance spectroscopy, revealing improved electrochemical performances. Square wave anodic stripping voltammetry (SWASV) was used to achieve the simultaneous detection of Pb(II) and Cd(II) at trace level, obtaining satisfactory LOD of 3.6 ppb and 15.3 ppb respectively; and sensitivity of 0.49 μA/ppb and 0.57 μA/ppb in tap water.

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Electrochemical detection and removal of lead in water using poly(propylene imine) modified re-compressed exfoliated graphite electrodes

Cited by 36 publications

References 32 publications

A review of exfoliated graphite

A review of exfoliated graphite

An Exfoliated Graphite-Based Electrochemical Immunosensor on a Dendrimer/Carbon Nanodot Platform for the Detection of Carcinoembryonic Antigen Cancer Biomarker

A Poly(Propylene Imine) Dendrimer and Carbon Black Modified Flexible Screen Printed Electrochemical Sensor for Lead and Cadmium Co‐detection

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