Micellar-enhanced ultrafiltration of copper ions using sodium dodecyl sulfate and its mixture with Brij 35, Tween 80 and Triton X-100

Abstract

The performance of copper ion removal using sodium dodecyl sulfate (SDS) and its mixtures with Brij 35, Tween 80 (TW80) and Triton X-100 (TX100) by micellar-enhanced ultrafiltration (MEUF) was investigated. The effects of the molar ratio of nonionic surfactant to SDS on the critical micelle concentration (CMC) of SDS/Brij 35, SDS/TW80 and SDS/TX100, the removal efficiency of Cu(2+), the residual concentration of SDS in the permeate solution and the permeate flux were tested. The results showed that the CMCs of the mixed surfactants were sharply less than that of pure SDS. The removal efficiencies of Cu(2+) were up to the maximum values 98.3 and 95.8% when the molar ratios of Brij 35 and TW80 to SDS were 0.3, and it was 93.5% given 0.7 molar ratio of TX100 to SDS. The concentration of SDS in the permeate decreased dramatically with the addition of nonionic surfactant, and the permeate flux decreased slightly as the molar ratio increased. Compared with the performance by single SDS, the mixed SDS/Brij 35, SDS/TW80 and SDS/TX100 at an optimum composition could result in not only higher rejection of Cu(2+) but also much less dosage of surfactant and concentration of SDS in the permeate.

Solubilization in Mixed Micelles Studied by Molecular Dynamics Simulations and COSMOmic

“…Synergistic effects refer to an interaction of the surfactants leading to a smaller mixed cmc, resulting in a smaller amount of surfactants needed to form micelles, as well as the increase in solubilization capacity. These effects have experimentally been observed by different groups. ,− ,− , In general, it is difficult to obtain the cmc in all-atom MD simulations; therefore, we investigate the structures and compositions of the micelles.…”

“…These effects have experimentally been observed by different groups. 2,[4][5][6][13][14][15][16]36 In general, it is difficult to obtain the cmc in all-atom MD simulations; therefore, we investigate the structures and compositions of the micelles.…”

“…Micelles formed by these surfactants can be used for extraction processes, as they can solubilize different components (solutes). Therefore, the formation of micelles, especially of mixed micelles, is of great importance for multiple technical applications. − The self-assembly process takes place on a microscopic scale and is rather expensive to study via experiments. However, computer simulations provide an alternative to calculate micellar properties and to gain a deeper insight into the process of micelle formation. − There are several simulation approaches available, which have different advantages.…”

“…Due to the fact that most publications on mixed micelles are mainly based on experiments, ,,− approaches for simulations and predictions of these systems are rare. Especially, when new processes are developed, a fast screening of optimal surfactant systems is desired.…”

Micellar enhanced ultrafiltration (MEUF) of metal cations with oleylethoxycarboxylate

“…One approach, also typically employed in detergency [13,14], is the use of mixed micellar solutions, where the addition of a small amount of a nonionic surfactant to the ionic surfactant reduces the cmc significantly and also allows for efficient heavy metal removal of, e.g. Cd 2 þ [15] or Ni 2 þ [16]. A second approach is the use of twoheaded gemini surfactants which have a low cmc as ionic surfactants [17], but their synthesis is often more complex.…”