Equilibrium and Kinetic Aspects of Hg(II) Extraction from Natural Waters with Diphenylthiocarbazone

Abstract

A diphenylthiocarbazone (dithizone) based liquid‐liquid extraction method of general utility is proposed for small‐scale Hg(II) extraction from natural waters. The quantitative aspects related to the extraction are studied in terms of distribution of mercury dithizonate in carbon tetrachloride‐water system at 293 K (20±1°C). Various distribution constants related to the reagent and the complex formed are evaluated. The equilibrium and kinetic studies of extraction and complex formation are analytically based on atomic absorption and colorimetric methods. Local natural waters were subjected to the proposed method for Hg(II) removal. The method is found to be capable of removing above 98% mercury in a single‐step extraction under the conditions evaluated in terms of matrix pH, equilibration time and amount of reagent.