In situ detection and removal of metal ion by porous gold electrode

A sensing electrode for the detection of heavy metal ions in aqueous solution selectively measured the concentrations of target materials on its functionalized surface, which has affinity to target metal ions. Target ions were adsorbed simultaneously on the functionalized electrode during the sensing process. Therefore, to understand this, experiments on the amperometric response and isotherms with an initial concentration of Hg2+ were tested. Detection current was dependent on the concentration of Hg2+, and the equilibrium concentration of Hg2+ adsorbed to the electrode showed a Langmuirian shape. Correlation between the detection current and removal capacity for Hg2+ revealed that it is possible to estimate the adsorbed concentration on the electrode during the sensing step. Although the macroporous gold electrode prepared herein showed relatively low adsorption performance compared to conventional adsorbents, when we prepare nanoporous gold electrodes with a uniform nanopore structure and large surface area, in situ detection and simultaneously removal of metal ions by nanoporous gold electrode will be possible.

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► Target ions were adsorbed simultaneously on electrode during the sensing process.
► Detection current was dependent on the concentration of Hg2+.
► Correlation between the detection current and removal capacity for Hg2+.
► Possible to estimate the adsorbed concentration on the electrode during the sensing step.