Calcium Chelating Sugar-Based Surfactants for Hard-Water Detergency

Hard water can decrease the detergency efficiency of surfactants due to a significant concentration of divalent cations as Ca2+ or Mg2+. The formulation of a cleaning detergent must be modified and it is usual to add more surfactants or a huge quantity of sequestrating agents. This supplementary addition can have deleterious effects on the environment and increases the price of the formulation. A surfactant, presenting both detergency capacities in the presence of Ca2+ and Ca2+ chelating properties, would be of great interest. In this paper, we report on Ca2+ extraction with sugar-based chelating surfactants using an experimental device, namely a flotation column, as both chelating properties and foaming properties in the presence of Ca2+ are important in the flotation process as well as in detergency. Among all the sugar-based surfactants tested, a few of them were able to extract calcium and thus demonstrated the expected characteristics.