Tripolyphosphate

Sodium tripolyphosphate (STPP) is a commercially accessible, low-cost, and non-hazardous additive that dissolves in water (Palmeira-de-Oliveira et al. in Int J Pharm 421:130–134, 2011). STPP (Fig. 13.1) is commonly found in animal and human food items. STPP has been used in some chemical processes, including pH buffering, insoluble deflocculating reagents, industrial hygiene commodities, and emulsifying oily substances (Wawrzynczyk et al. in Water Res 42:1555–1562, 2008). Because of its phosphate groups, STPP has an affinity for cationic functionalities, such as amino groups and metallic cations. To modify the chitosan properties, it was established that cross-linked crystallization of amino groups in the chitosan molecule could be used as a method by which chitosan could be prepared to encapsulate drugs and to adsorb metal-ions adsorption (Mi et al. in Polymer (Guildf) 44:6521–6530, 2003). It was discovered that STPP interacts with Ca2+ cations preferentially to form stable complexes, reducing the negative effects of metal ions (e.g., Ca2+ cations on diaspore and kaolinite dispersion).