Electrochemical Techniques for the Extraction of Heavy Metals in Industry: Concepts, Apparatus And Costs

Heavy metal pollution of water has become a global issue and is especially problematic in some developing countries. Heavy metals are toxic to living organisms, even at very low concentrations. Therefore, effective and reliable heavy metal detection in environmental water is very important. Current laboratory-based methods used for analysis of heavy metals in water require sophisticated instrumentation and highly trained technicians, making them unsuitable for routine heavy metal monitoring in the environment. Consequently, there is a growing demand for autonomous detection systems that could perform in situ or point-of-use measurements. Microfluidic detection systems, which are defined by their small size, have many characteristics that make them suitable for environmental analysis. Some of these advantages include portability, high sample throughput, reduced reagent consumption and waste generation, and reduced production cost. This review focusses on developments in the application of microfluidic detection systems to heavy metal detection in water. Microfluidic detection strategies based on optical techniques, electrochemical techniques, and quartz crystal microbalance are discussed.

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Electrospun Nanofibers and Electrochemical Techniques for the Detection of Heavy Metal Ions

Materials ◽

10.3390/ma14113000 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3000

Author(s):

Angela Malara ◽

Antonio Fotia ◽

Emilia Paone ◽

Giulia Serrano

Keyword(s):

Heavy Metals ◽

Anodic Stripping Voltammetry ◽

Electrochemical Techniques ◽

Electrospun Nanofibers ◽

Stripping Voltammetry ◽

Current Status ◽

Electrochemical Technique ◽

Sensing Material ◽

Wide Range ◽

Anodic Stripping

Contamination by heavy metals is currently one of the most environmental concerns especially due to the toxicity, pervasiveness, and persistence of these substances. As they are not biodegradable, heavy metals are harmful not only for water, air, and soil but also for human health, even in very low traces. There is therefore a pressing need to develop an efficient, economic, and rapid analysis method to be applied in a wide range of conditions and able to detect very low contaminants concentrations. Currently, the most novel solution in this field is represented by the combination of electrospun nanofibers and highly sensitive electrochemical techniques. It has been proved that nanofibers, due to their outstanding properties, perfectly fit as sensing material when trace concentrations of heavy metals were investigated by anodic stripping voltammetry, envisaged as the most sensitive electrochemical technique for this kind of measurements. This work aims to provide an overview of the latest trends in the detection of contaminants by the simultaneous use of electrospun fibers and anodic stripping voltammetry. Indeed, a clear and comprehensive vision of the current status of this research may drive future improvements and new challenges.

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Hydrothermal Synthesis of Carbon Nanotubes-Polyaniline(CNT-PANI)Composites and Preliminary Electrochemical Characterization of CNT-PANI Coatings

Materiale Plastice ◽

10.37358/mp.20.3.5396 ◽

2020 ◽

Vol 57 (3) ◽

pp. 238-248 ◽

Cited By ~ 1

Author(s):

Laura-Madalina Cursaru ◽

Ana-Maria Mocioiu ◽

Ioan Albert Tudor ◽

Roxana Mioara Piticescu

Keyword(s):

Heavy Metals ◽

Carbon Nanotubes ◽

Hydrothermal Synthesis ◽

Glassy Carbon Electrode ◽

Glassy Carbon ◽

Electrochemical Techniques ◽

Modified Electrodes ◽

Carbon Electrode ◽

Mass Ratio ◽

Synthesis Time

Heavy metals have a major contribution to biosphere pollution due to toxicity. The detection and monitoring of the environmental agents in soil, water and air is very important for the general health of humans and animals. It has been recently shown that electrochemical techniques such as differential pulse voltammetry (DPV) and square wave anodic stripping voltammetry (SWASV) using modified electrodes are very attractive methods for detecting heavy metals. The aim of this paper is to demonstrate the potential of hydrothermal process combined with electrochemical techniques to obtain modified electrodes based on functionalized carbon nanotubes (CNTs) and polyaniline (PANI) for metals detection. Commercial multi-walled carbon nanotubes (MWCNT) were functionalized by a mixture of HNO3/H2SO4 and further used for hydrothermal synthesis of CNT-PANI composites with different mass ratios. The resulted powders were analyzed by spectral (Fourier-Transform Infrared Spectroscopy) and thermal (Differential Scanning Calorimetry) methods, and then dispersed in a surfactant/electrolyte solution for preliminary electrochemical experiments (cyclic voltammetry, CV and DPV) to obtain modified electrodes. The influence of the CNT: PANI mass ratio and the synthesis time on the formation of composites with the desired structural and electrochemical properties were studied. It was found that CNT-PANI composite powder having mass ratio 1:4 and synthesis time 3h has the best structural and thermal characteristics and formed a weakly conductive film on the surface of the glassy carbon electrode. Preliminary electrochemical tests revealed the electroactive forms of polyaniline, through the presence of characteristic oxidation peaks but also reduction peaks, corresponding to reversible redox reactions, demonstrating that glassy carbon electrode has been electrochemically modified with CNT-PANI coatings. Further studies will be conducted to test the potential application of glassy carbon electrode modified with CNT-PANI coatings as electrochemical sensor for heavy metals detection.

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Sampling and analysis of the air-water interface with SEM and EDS of microlayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157000 ◽

1989 ◽

Vol 47 ◽

pp. 1004-1005

Author(s):

Randall W. Smith ◽

John Dash

Keyword(s):

Heavy Metals ◽

Surface Microlayer ◽

Surface Films ◽

Water Interface ◽

Physical Processes ◽

Infrared Spectroscopic Analysis ◽

Eds Analysis ◽

Air Water Interface ◽

Significant Area ◽

Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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