Rapid characterization of arsenic adsorption on single magnetite nanoparticles by collisions at microelectrodes. Issue 7 (17th June 2020)

• Record Type: Journal Article
• Authors: Hosseini Narouei, Farideh; Andreescu, Daniel; Andreescu, Silvana
• Is Part Of: Environmental science. Volume 7:Issue 7(2020)
• Page Start: 1999
• Page End: 2009
• Publication Date: 2020-06-17
• Subjects: Environmental sciences -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0en00336k
• Languages: English
• ISSNs: 2051-8153

Abstract

Abstract : A rapid and inexpensive method to analyze redox properties of magnetite nanoparticles and quantify arsenic adsorption by single particle collision electrochemistry. Abstract : We describe a rapid and sensitive electrochemical approach to evaluate the interaction of arsenite (As 3+ ) with magnetic Fe3 O4 nanoparticles (MNPs) by single particle collision electrochemistry (SPCE). The method is based on direct measurements of the (As 3+ ) adsorbed on single MNPs, quantified via the oxidation of As 3+ to As 5+ at 0.4 V vs. Ag/AgCl, as the As-MNPs collide with a gold microelectrode (AuME). Measurement of the intensity of current spikes and the charge passed per impact spike provides a measure of As 3+ content adsorbed per MNP. The total calculated charge passed at AuME was monitored over 400 s collision time and the As 3+ adsorption was quantified at different pH and environmental conditions. The charge increased significantly for MNPs exposed to a natural organic material, humic acid (HA), at concentrations of up to 5 ppm, and when the pH of the solution was between 6 and 8, indicating enhanced adsorption. The concentration of As 3+ (0.013–0.036 fM As/MNP) was found to correlate well with the initial concentration of As 3+ in solution (0.001–10 μM), suggesting that the method can also be used as an analytical tool to determine As contamination in environmental samples. The results were confirmed with spectroscopic techniques and demonstrate As 3+ adsorption. Overall, this study demonstrates the capability of SPCE to fundamentally probe the surface properties of magnetite with high resolution and elemental specificity allowing a direct ultrasensitive assessment of the As 3+ loading on individual MNPs. This approach could be used as a simple cost effective and fast screening tool to evaluate heavy metal ion adsorption on nanomaterial sorbents for environmental monitoring and remediation applications.