Voltammetric study of the affinity of divalent heavy metals for guanine functionalized iron oxide nanoparticles
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2020-11-14 |
| Journal | Proceedings of 7th International Electronic Conference on Sensors and Applications |
| Authors | Simona Sawan, Khalil Hamze, Ali Youssef, Rayyan Boukarroum, Kamal H. Bouhadir |
| Institutions | Centre National de la Recherche Scientifique, Université Claude Bernard Lyon 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This study details the development and performance of a highly sensitive electrochemical sensor for detecting trace divalent heavy metal ions (Cu2+, Pb2+, and Cd2+) using functionalized iron oxide nanoparticles.
- Novel Material Platform: A novel composite material, guanine hydrazide (GH) functionalized (3-aminopropyl) triethoxysilane (APTES) coated iron oxide (Fe3O4) nanoparticles (GH-APTES-Fe3O4), was synthesized for heavy metal capture.
- Sensor Configuration: The material was deposited onto a boron-doped diamond electrode (BDDE) and analyzed using Square Wave Voltammetry (SWV).
- High Sensitivity: The sensor exhibited excellent sensitivity, achieving 171.6 µA/µM for Cu(II) and 156 µA/µM for Pb(II) in the low micromolar range.
- Excellent Reproducibility: Reproducibility was confirmed with low Relative Standard Deviation (RSD) values: 4% for Cu(II), 5% for Pb(II), and 10% for Cd(II) over five independent measurements.
- Adsorption Selectivity: Electrochemical investigation of adsorption isotherms revealed a clear affinity order for the nanoparticles: Cu2+ > Pb2+ > Cd2+.
- Dual Functionality: The material is designed for both onsite monitoring (sensing) and potential removal of non-biodegradable heavy metal contaminants.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Nanoparticle Composition | Fe3O4 | N/A | Core material |
| Functionalization Ligand | Guanine Hydrazide (GH) | N/A | Active binding site for heavy metals |
| Average Particle Diameter | 45 | nm | Spherical morphology |
| Adsorption Affinity Order | Cu2+ > Pb2+ > Cd2+ | N/A | Determined electrochemically |
| Cu(II) Detection Performance | |||
| Linear Response Range 1 | 0.209 to 1.03 | µM | Measured by SWV |
| Sensitivity (Cu(II)) | 171.6 | µA/µM | Highest sensitivity reported |
| Reproducibility (RSD) | 4 | % | Over five measurements |
| Pb(II) Detection Performance | |||
| Linear Response Range 1 | 0.232 to 0.809 | µM | Measured by SWV |
| Sensitivity (Pb(II)) | 156 | µA/µM | |
| Reproducibility (RSD) | 5 | % | Over five measurements |
| Cd(II) Detection Performance | |||
| Linear Response Range 1 | 0.483 to 4.97 | µM | Measured by SWV |
| Sensitivity (Cd(II)) | 101.4 | µA/µM | |
| Reproducibility (RSD) | 10 | % | Over five measurements |
Key Methodologies
Section titled “Key Methodologies”The synthesis and evaluation process involved controlled chemical functionalization followed by advanced electrochemical analysis:
- Nanoparticle Synthesis: Iron oxide (Fe3O4) nanoparticles were synthesized, likely via co-precipitation or thermal decomposition (though specific synthesis details are not provided in the abstract).
- Silane Coating: The Fe3O4 nanoparticles were coated with (3-aminopropyl) triethoxysilane (APTES) to introduce reactive amine groups on the surface, facilitating subsequent functionalization.
- Guanine Functionalization: Guanine hydrazide (GH) was covalently attached to the APTES-coated Fe3O4 nanoparticles, creating the final GH-APTES-Fe3O4 sensing material.
- Material Characterization:
- Fourier Transform Infrared Spectroscopy (FTIR) was used to confirm successful chemical bonding and functionalization steps.
- Energy-Dispersive X-ray Analysis (EDX) and X-ray Diffraction (XRD) were used to control the synthesis and structural integrity.
- Scanning Electron Microscopy (SEM) was used to determine morphology, confirming spherical nanoparticles with an average diameter of 45 nm.
- Electrode Fabrication: A boron-doped diamond electrode (BDDE) was coated with the synthesized GH-APTES-Fe3O4 nanoparticles to create the working sensor.
- Electrochemical Analysis: Square Wave Voltammetry (SWV) was employed to evaluate the electrochemical interaction and quantify the concentration of divalent heavy metal ions (Cu2+, Pb2+, Cd2+).
- Adsorption Study: Adsorption isotherms were investigated electrochemically to determine the adsorption capacity and selectivity order of the nanoparticles towards the target heavy metals.
Commercial Applications
Section titled “Commercial Applications”The development of highly sensitive, reproducible, and selective sensors for heavy metals has direct implications across several critical engineering sectors:
- Environmental Monitoring and Remediation:
- Onsite, real-time monitoring of heavy metal contamination in rivers, lakes, and industrial effluent.
- Integration into portable or remote sensing platforms for rapid environmental assessment.
- The magnetic core (Fe3O4) suggests potential for magnetic separation, allowing the material to be used for both sensing and removal/remediation of contaminants from water sources.
- Wastewater Treatment:
- Continuous monitoring of discharge streams to ensure compliance with strict regulatory limits for trace heavy metals.
- Development of cost-effective, reusable filtration or adsorption media based on the high-affinity functionalized nanoparticles.
- Food Safety and Agriculture:
- Monitoring heavy metal accumulation in agricultural water supplies and food products, addressing concerns about bioaccumulation in the food chain.
- Chemical and Process Engineering:
- Quality control and monitoring of ultra-pure water systems used in semiconductor manufacturing or pharmaceutical production, where trace metal contamination must be minimized.
View Original Abstract
The smallest concentrations of heavy metal ions can be harmful to both the environment and human health. They are non-biodegradable and can accumulate all along the food chain, thus their onsite monitoring and removal is of great importance. In this work, a novel material based on (3-aminopropyl)triethoxysilane (APTES) coated iron oxide (Fe3O4) nanoparticles functionalized with guanine hydrazide (GH) was elaborated. Fourier transform infrared spectroscopy, energy-dispersive X-ray analysis and X-ray diffraction were used to control the synthesis and functionalization steps of the nanoparticles. The morphology and particle size were studied by scanning electron microscopy. Spherical nanoparticles with an average diameter of 45 nm were obtained. A boron-doped diamond electrode coated with GH-APTES-Fe3O4 nanoparticles was used to evaluate the electrochemical interaction of some divalent heavy metal ions with guanine hydrazide. Adsorption isotherms were investigated electrochemically and it was shown that the adsorption capacity of the nanoparticles towards heavy metals decreased in the following order: Cu2+>Pb2+>Cd2+. Moreover, the signals generated by square wave voltammetry exhibited two distinct linear response ranges; the first linear plot lies in the range of 0.209 to 1.03 μM with a sensitivity of 171.6 µA/µM for Cu (II), 0.232 to 0.809 μM with a sensitivity of 156 µA/µM for Pb (II) and 0.483 to 4.97 μM with a sensitivity of 101.4 µA/µM for Cd (II). Furthermore, an excellent reproducibility was achieved with relative standard deviation (RSD) values of 4%, 5% and 10% respectively over five independent measurements.