Adsorption of Anionic Surfactant onto Malaysian Sandstone

The adsorption of surfactant from aqueous solution study is very significant
on chemical enhanced oil recovery (CEOR). One of chemical enhanced oil recovery
identified was surfactant flooding. In present, the potential of surfactant flooding in
Malaysia is still in development process and needs laboratory data like surfactant
adsorption to assist the field data required. Surfactant losses due to the adsorption on
the reservoir rocks weaken the efficiency of surfactant to decrease the interfacial
tension between oil and water. For final year research project, a study to investigate
the adsorption of anionic surfactant onto Malaysian sandstone has been done with
assistance from UTP Enhanced Oil Recovery (EOR) Research Centre. The study was
started with determination of critical micelle concentration (CMC) of anionic
surfactant by conductivity method to get a maximum concentration at which the
surfactant is adsorbing onto the sandstone. The main part of the researches was the
static adsorption test where the different concentration of anionic surfactant was
mixed with Malaysian sandstone in a continuous mixing environment for 24 hours.
The unknown surfactant concentration was represented as absorbance detected by
UV-Vis spectrophotometer. The amount of surfactant adsorbed was calculated by
subtracting the concentration of anionic surfactant after adsorption from the initial
concentration. An isotherm relating the adsorption density with final concentration of
surfactant has been developed with the isotherm following Somasundran isotherm.
The isotherm shows three mechanisms of surfactant adsorption from low to high
surfactant concentration. It was concluded that this adsorption study is valid as
fundamental and reference to assist the laboratory studies in determining the potential
of surfactant flooding in Malaysia.