Trace metal analysis of geothermal waters

Authors

  • Harry L. Engle Institute of Chemistry, University of the Philippines, Diliman, Quezon City
  • Cherry B. Pascual Institute of Chemistry, University of the Philippines, Diliman, Quezon City

DOI:

https://doi.org/10.26534/kimika.v12i1.37-44

Keywords:

geothermal waters, arsenic, mercury, gold, anodic stripping voltammetry

Abstract

The determination of trace amounts of arsenic, mercury, and gold in geothermal water samples by differential pulse anodic stripping voltammetry (DPASV) was investigated. Optimum parameters affecting voltammetric behavior, such as deposition potential, supporting electrolyte, and nature of working electrode were first determined. A thin film gold electrode (TFGE) was used for the analysis of As(III) in 6 M HCl, and Hg(II) in 0.1 M HNO3. The analysis of Au(III) was carried out in 0.2 M HCl using a glassy carbon electrode (GCE). The deposition potentials employed for each metal were -0.150 V, 0.000 V, and -0.500 V for As, Hg, and Au, respectively.

The stripping peaks observed at -0.05 V. +0.50 V and +0.70 V (vs. SCE) for As(III), Hg(II) and Au(III), respectively, were utilized for their quantitative determination. The detection limit for each metal were 0.2 ppb for As(III), 0.02 ppb for Hg(II) and 0.04 ppb for Au(III). Different sample pretreatment procedures were devised for each metal. The concentration ranges obtained by DPASV were 6.6- 10.1 ppm As(III), 0.02- 0.07 ppm Hg(II) and 0.2- 8.4 ppb Au(III) in some geothermal water samples analyzed.

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How to Cite

Engle, H. L., & Pascual, C. B. (1996). Trace metal analysis of geothermal waters. KIMIKA, 12(1), 37–44. https://doi.org/10.26534/kimika.v12i1.37-44

Issue

Vol. 12 (1996)

Section

Research Articles

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