Formulation of critical micellar concentration of non- phosphate detergents by surface tension measurement

Abstract

Non-phosphate builders which are environmentally friendly are required for use in detergent formulation to replace the sodium tri-poly phosphate (STPP). Phosphates are excellent fertilizer for algae, bacteria, and other flora and fauna in rivers, lakes and  oceans, making them bloom at very rapid rates. This exhausts the oxygen supply both in the surface and in the bottom layers of water bodies, and leading the death of fishes. Sodium metasilicate a non-phosphate builder from Lokoja Quartzite was used to  formulate a non-phosphate biodegradable synthetic detergent using 25%, 50% and 75% sodium hydroxide concentrations. The critical micellar concentration (CMC) of a non-phosphate  detergent was determined via measurement of surface tension. This method is rapid, reliable and cheap compared to the  fluorescence polarization method which required a sophiscated materials such as 1,6-diphenyl-1,3,5-hexatriene as fluorescence probe. The detergents formulated with 75% and 50% sodium hydroxide concentrations have CMC values of 8.6685 mM and 6.9348 mM respectively. From this study, a non phosphate builder synthesized from Lokoja Quartzite has potential of protecting aquatic animals when compared with the conventional STPP currently used in our detergent formulation. Also, the simple and economical approach for determination of detergent’s CMC has demonstrated it’s potentials. These values agree well with the literature value ranges between 7 to 10 mM.

Keywords: Detergent; CMC; Surfactants; Non-phosphate;  1,6-diphenyl-1,3,5-hexatriene