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Title: REMOVAL OF SOME METAL IONS FROM AQUEOUS SOLUTIONS USING A MAGNETIC ION EXCHANGE RESIN WITH SULPHONATE FUNCTIONALITY

Author: A.A. Atia, A.M. Donia and A.M. Yousif

Year: 2009

Publisher: European Water Resources Association (EWRA)

Description:

Ion exchange onto low cost media such as synthetic resin ion exchangers offers an attractive and inexpensive option for the removal of metal ions from aqueous solutions. Magnetic resin ion exchangers have special interest due to easy separation of the loaded resin from waste stream using an external magnetic field. In this work, magnetic ion exchanger with sulphonate functionality was prepared and characterized using FT-IR. The investigated resin is characterized by easy of solid/liquid separation due to the imparted magnetic properties of resin. Good stability in both HNO3 and NaOH where an uptake efficiency of 98.1 ±0.5% was recorded over three measurements. The uptake behavior of the resin towards different metal ions using batch experiments at different experimental conditions such as pH, contact time, initial metal ion concentration was studied. It is found that a selective separation of Cu(II) from Ag(I) and Hg(II) in the strong acidic media from their aqueous mixture is obtained. The resin showed a powerful uptake behavior towards the studied metal ions. The uptake follows the sequence Ag(I) > Hg(II) > Cu(II) with maximum uptake efficiencies of 4.1, 3,0 and 2.9 mmol/g, respectively. The resin obtained showed comparable uptakes to the commercial resin (Dowex Marathon C) but with faster kinetics. Kinetic characteristics of uptake process were evaluated where they were found to follow first order kinetics. Thermodynamic parameters (ΔH°, ΔS° and ΔG°) were evaluated. The positive values of ΔH° for all adsorption processes indicate the endothermic nature. The negative values of ΔG° indicate that the adsorption reaction is spontaneous. The observed positive value of ΔS° indicates a more randomness state due to the liberation of water molecules during the exchange process. The regeneration experiments showed efficiency > 95% using 0.4 M EDTA for the studied metal ions. Column experiments were performed to recover the metal ions at different flow rates to conclude the best conditions for using a column of the investigated resin in the industrial field.