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. 1. 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 ionic impurities can lead to problems in cooling and heating systems, steam generation, and manufacturing. 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. Therefore the necessity of obtaining water having low level of hardness has taken place inside important occupational areas for industries such as leather production [1]. 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 [2–4]. Water softening using electrochemical techniques has gained attention [5]. 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]. The ion exchange resins have numerous commercial and industrial uses particularly in water purification and removal of metal ions at very low concentrations in chemical process of industries [7]. Some polymeric resins having strongly acid sulfonic or weakly acid carboxylic functionalities are usually used in ion exchange processes [8–11]. A method has been focused on the combination of ultrasound and ion exchange for removal of hardness of calcium and magnesium from water [12]. Some methods have been conducted for removing Ca(II) and Mg(II) from water by using chelating resins with high
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