Development of novel sorbents for the determination of mercury in waters by cold vaporatomic absorption spectrometry

Abstract

Mercury is one of the most toxic heavy metal ions to all living organisms. A novel solid support with selective functional groups was developed for mercury sorption from waters prior to its determination by cold vapor atomic absorption spectrometry. The support was prepared by immobilization of several functional groups (amino, mercapto, etc.) on silica. Among the sorbents developed, 3-MPTMS-silica has been shown to be an efficient material for the sorption of mercury species due to its selectivity. Sorption experiments were performed to optimize the necessary parameters and conclusively, sorption pH of 7.0, reaction temperature of 25 oC, sorbent amount of 10.0 mg and shaking time of 30 min were applied throughout the study. Various mineral acids, organic acids, oxidizing agents and sulfur- or nitrogen-containing ligands were tried for the elution of mercury species and 2.0 M TGA was found to offer the maximum desorption. The validity of the method was checked via spike sorption experiments with four different types of water; namely, ultra pure, bottled drinking, tap and sea water. The method worked efficiently (>95%) for all types of water. Permeable reactive barriers, such as zero-valent iron and zero-valent copper were also applied for the removal of mercury species. Similar optimization parameters with 3-MPTMS-silica were also obtained for both sorbents. The method validation was also performed and although sea water is a heavy matrix, high uptake results were achieved for both sorbents.