Applications of microelectrodes and scanning electrochemical microscopy (SECM) to complex environmental interfaces

• Main Author: Perdomo Marin, Ana Cristina
• Other Authors: Denuault, Guy
• Published: University of Southampton 2018
• Subjects: 540
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.766843

During this research, microelectrodes were employed as sensors and scanning electrochemical microscopy (SECM) probes to further understand two complex environmental interfaces: the sea surface microlayer (SML), and the iron-groundwater interface at permeable reactive barriers (PRBs). The water-air and water-SML interfaces were investigated through the oxidation current of a model redox pair at a Pt submarine microdisc. Chronoamperometry and cyclic voltammetry allowed us to determine the concentration and diffusion coefficients of the redox species at different tip-substrate distances with respect to each interface. The approach curves recorded revealed information regarding the stability of the water-air interface over time and its susceptibility to the acquisition mode, size of the meniscus and the ratio of glass/microwire of the tip (RG). The iron-groundwater interface was investigated in terms of the corrosion activity and ReO₄^- uptake from groundwater of iron from different sources and particle sizes. The relationship between the corrosion of iron and the uptake of ReO₄^- was investigated using supplementary techniques like laser ablation inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The results obtained represented a basis to understand the TcO₄^- uptake from groundwater at PRBs.