Abstract

An analytical method was developed for the separation and preconcentration of Cu²⁺, Zn²⁺, Pb²⁺, Cd²⁺, Ni²⁺ and Fe³⁺ from surface water samples collected from ten locations at Suez Gulf, using silica gel chemically modified with zirconium (IV) phosphate. The effects of pH value, time of stirring, concentration of eluting acids and some common ionic species on the separation and preconcentration of the investigated metal ions in synthetic aqueous solutions were firstly studied. The results indicate that the optimum conditions for separation are pH = 5.0- 5.5 and time of stirring = 30 min. HNO₃ is better eluent for the investigated metal ions than HCl hence 2M HNO₃ was used as an eluent. Citrate and EDTA severely affect on the recovery of the metal ions therefore the water samples were previously oxidized to digest organic matter prior to the application process.

Key words: Separation, preconcentration, modified silica, metals, water.