Synthesis and Surface Properties of a Natural Surfactant Obtained from Crude Glycerine Through Basic Hydrolysis and Carboxymethyl Cellulose Additivation
Surfactants from natural sources have been emerged as a good alternative to synthetics due to their unique properties such as production from renewable sources, biodegradability, low environmental impact and good stability. The current work deals with the synthesis of a natural anionic surfactant based on a biodiesel residue from soy oil and the characterization of the surface properties of this product. The natural surfactant was synthesized by hydrolysis of fatty acids in the presence of an alkaline agent and added with carboxymethyl cellulose (NaCMC). For this purpose, crude glycerin was characterized by high resolution spectroscopy (NMR), high performance liquid chromatography (HPLC), physical-chemical characterization and fatty acids were identified by gas chromatography - mass spectrometry (GC-MS).The Natural surfactant was characterized by Fourier-transform infrared spectroscopy (FTIR) and surface properties were determined by critical micellar concentration (c.m.c.) and zeta potential measurements. The GC-MS confirm the presence of methyl esters of C18 fatty acids, mainly stearic, oleic and linoleic. The natural surfactant (NS) and Additivated Natural Surfactant with NaCMC (ANS) wich one exhibited two new groups with stretches of 1042.77 and 878.41 cm-1 in the infrared spectra referring to the C-O and C-C bands, indicating possible physical interaction and formation of a new NAS / CMC compound.Zeta potential results showed that natural surfactant with the presence of carboxymethyl cellulose there is a tendency to increase the negative load due to carboxyl groups.
Keywords - Crude glycerin, basic hydrolysis, natural surfactant, carboxymethylcellulose.