Abstracts Book - IMRC 2018

• SA6-O020
INFLUENCE OF DIFFERENT SURFACTANTS ON ZETA POTENTIAL
AND ISOELECTRIC POINT OF ALUMINA NANOFLUIDS
Karen Paola Cacua Madero 1,2 , Fredy Ordoñez Ramos 1,2 , Robison Buitrago Sierra 1 , Elizabeth
Pabón Gelves 2 , Bernardo Herrera 1
1
Instituto Tecnológico Metropolitano, Antioquia, Colombia. 2 Universidad Nacional de Colombia,
Antioquia, Colombia.
Alumina (Al2O3) nanoparticles are the most used material to prepare nanofluids.
Nanofluids consist in a dispersion of nanoparticles in a base fluid, used mainly
in heat transfer applications. However, agglomeration and sedimentation with
the time are the main concern to nanofluid applications in different heat
transfer devices. Zeta potential is an important parameter to determine the
surface charge of nanoparticles in suspension. The surface charge of
nanoparticles affects significantly their agglomeration behavior and their
control it is necessary to obtain a stable dispersion. Zeta potential is affected by
the suspension pH value and the different additives used during the nanofluid
preparation. When the zeta potential is zero the nanoparticles will agglomerate,
and the dispersion of the nanoparticles is lost, this point is known like isoelectric
point. In this study commercial Alumina nanoparticles (0.1 wt.%) were
characterized by SEM, EDS, DRX and TGA and dispersed in deionized water using
different surfactants types (Cetyltrimethylammonium bromide, CTAB; Sodium
dodecylbenzenesulfonate, SDBS and Tritón X-100) and concentrations (0.128,
0.032 and 0.064 wt.%). The pH values were varied (2-10) using Hydrochloric acid
and Sodium hydroxide to determine the zeta potential values and their
hydrodynamic size associated. Results shows that SDBS at a concentration of
0.064 wt.% (critical micelle concentration) shows the best dispersion conditions
to allow a high stability regardless of the pH value of the suspension.
Keywords: zeta potential, alumina nanofluids, isoelectric point
Presenting authors email: kpcacuam@unal.edu.co