Specific Salt and pH Effects on Foam Film of a pH Sensitive Surfactant

Abstract

Steady state foams made of a pH sensitive surfactant, nonaoxyethylene oleylether carboxylic acid, with ion complexing properties was studied using small angle neutron scattering (SANS). The effect of pH variation and salt addition on the foam film thickness was investigated and discussed in terms of the influent parameters stabilizing the foam such as surface properties and electrostatic effects determined by tensiometry and zeta potential measurements. The decrease in the film thickness by adding mono (Na(+)) and divalent (Ca(2+)) salts is classically explained by screening of the double layer in foam films (transverse interactions). On the contrary, addition of acid or complexing ion (Nd(3+)) results in an increase in the film thickness and can be analyzed in terms of cohesive forces between surfactants at the liquid/gas interface (lateral interactions). pH and specific salt effects revealed that foams produced by nonaoxyethylene oleylether carboxylic acid are of interest in the potential use of this surfactant in ion separation process.

Development of a New Material for Mine Fire Control

“…Slurry and air are restricted into an isolated state. A monolayer film will be formed on the surface of the slurry (Micheau et al, 2013;Pedersen et al, 2007). Surface tension has decreased to the minimum and foaming volume increases to the maximum.…”

Micellar enhanced ultrafiltration (MEUF) of metal cations with oleylethoxycarboxylate

“…RO90 has a very low cmc (about 170 times less than SDS) and after pH adjustment removal efficiency reaches almost to quantitative values showing that RO90 can successfully replace SDS in metal ion removal processes. It is expected that also the cmc of RO90 will decrease in the presence of metal ions as already shown by Micheau et al [27], but its cmc of 0.020 mM for pure water is already similarly low as the cmc of corresponding non-ionic surfactants, e.g. 0.24 mM for Triton X-100, so that a further decrease is not relevant.…”

Chemoenzymatic synthesis of the pH responsive surfactant octyl β-D-glucopyranoside uronic acid

“…The drop in the foam height correlates well with the measured value of pK a (3.32). At pH values above pK a , the surfactant is negatively charged causing electrostatic repulsion and an increase in hydration and thereby an increase in the area per head group (Micheau et al 2013) producing less cohesive forces at the surface (Chen and Tsai 1988). Similarly, electrostatic repulsion was suggested as the explanation for decreased foam stabilization by bovine serum albumin above or below its isoelectric point (Engelhardt et al 2012).…”