The effect of surfactant hydrophilic group on gas absorption rates

Abstract

A quiescent cell differential manometric absorption apparatus was used to study the effect of surfactant hydrophilic functional group on the rate of gas absorption. Carbon dioxide and water was chosen as the absorption system. Six surfactants were selected for study, namely: n-octanol, 4-oxtanol, lauryl diglycol amide, lauryl diethanol amide, sodium lauryl sulfate, and sodium lauryl benzene sulfonate. The last four surfactants were chosen because they are biodegradable and widely used in detergent formulations. Preliminary absorption tests were made using deionized water to determine the diffusion coefficient for the system. A value of 1.93 ± 0.05 × 10 −5 square centimeters per second was obtained. Absorption tests were made with the six surfactants at several bulk concentrations for each surfactant. The octanol with the hydroxyl group at a branched position was found to cause a higher resistance to gas absorption than with the hydroxyl group at the end of the hydrophobic chain. It was also found that increasing the molecular weight of the hydrophilic functional group decreased the resistance to gas absorption.