Removal of Hardness of Earth Alkaline Metals from Aqueous Solutions by Ion Exchange Method

Gulten Cetin

doi:10.1155/2014/621794

Abstract

An ion exchange process was introduced as an approach for softening of artificial hard water solutions. A strong acid cation exchange resin, Amberlite IR 120 [Na+], was used to reduce the hardness of water with the matrix of styrene-divinylbenzene copolymer having functional group as sulfonate. The ion exchange behavior of the ions of calcium and magnesium in synthetic solutions of hard water was investigated with the variables depending on pH, stirrer speed of the solutions and amount of the resin as a function of contact time between resin phase and hard water solution. The maximum ion exchange capacity was found to be 68 mg/g for Ca(II) and 12 mg/g for Mg(II) at pH 3.0. The method is a simple and efficient one to remove calcium and magnesium hardness from hard water solutions with the resin having more selectivity for calcium.

Highlights

The existence of the soluble Ca(II) and Mg(II) salts has caused unsuitable behavior of hard water solutions for drinking, watering, and the purposes of industrial
The following reactions show that the resin matrix has been converted to the H+ form from Na+ and the exchange reaction of calcium and magnesium has been summarized: R–SO3−Na+ + HCI 󳨀→ R–SO3−H+ + Na+ + CI−
The resin’s behavior is different for sorption of calcium and magnesium ions in solution and it is more selective for calcium than magnesium and exchange capacity is more high for calcium

Summary

Introduction

The existence of the soluble Ca(II) and Mg(II) salts has caused unsuitable behavior of hard water solutions for drinking, watering, and the purposes of industrial. The high calcium and magnesium concentrations have resulted in clogging of pipelines and heat exchangers through scaling as the form at carbonate, sulfate, or phosphate precipitates. The common methods used for removal of the metals of earth alkaline from aqueous solutions and softening of water can be classified as chemical precipitation, ultrafiltration, reverse osmosis, electrodialysis, adsorption, and ion exchange [2,3,4]. The packed bed of polypyrrole/polystyrene sulfonate electrodeposited porous carbon electrode has been used for continuous water softening from flowing artificial hard water solutions [6]

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Conclusion