Ion flotation using carboxylate soaps: role of surfactant structure and adsorption behaviour

Structure changes in micelles and adsorbed layers during surfactant polymerization

“…This also lies within the range of previous measurements, but is significantly higher than the value of 57 Å 2 found for DTAB [42]. This suggests that some of the polar methacryloyl groups are in contact with water, forming a bent or hairpin conformation at the air-water interface similar to a bolaform surfactant [43], as previously suggested by Abe et al [44] and Hamid and Sherrington [27].…”

Flotation using sodium dodecyl sulphate and sodium lauroyl isethionate for rapid dewatering of Mg(OH)2 radwaste suspensions

“…Previous work into the effect of the hydrophobic tail lengths in carboxylate soap collectors found that increasing the hydrophobic tail length increased the recovery yield in ion otation. 39 However, in the present case, the increase in chain length of the SLI did not enhance otation, largely due to the reduced adsorption density from the larger headgroup as shown in the surfactant-particle adsorption density data in Table 2. Also, increasing the hydrophobicity of particles has a trade off with foam stability.…”

“…16,17 As an alternative to gravitational separation, otation has received increasing interest from researchers for radwaste separation, as it has been shown to be an extremely rapid dewatering technique, and is already commonly utilised in the minerals, water treatment and paper industries. [18][19][20][21][22][23][24][25][26] Previous investigators have studied a range of variables that affect otation performance, including particle contact angles, [27][28][29] bubble size distribution, 25,30 foam stability, 18,[31][32][33][34] suspension/collector concentration, 29,35,36 collector adsorption density, 23,35,37,38 collector hydrophobicity, [39][40][41] particle coagulation and hydrodynamic consequences of variable PSDs. 15,28,42,43 Research into otation of Mg(OH) 2 , a corrosion product of the fuel cladding alloy at Sellaeld, 2,6 has received little interest, but similar mineral particulates have been shown to be effectively separated using otation facilitated with anionic surfactant collectors, such as alkyl sulphates including sodium dodecyl sulphate (SDS).…”

Ion Binding and the Apparent Selectivity Coefficient for Ion Flotation

“…In the first, a dilute solution of CTAB and potassium iodide was prepared in excess sodium acetate (2.0 mM). As the acetate ion binds extremely weakly to quaternary ammonium surfactants, it does not compete effectively with either bromide or iodide. − In the second, DTAB was mixed with dilute potassium iodide and concentrated sodium chloride solutions. Chloride is also a more weakly binding ion than either bromide or iodide.…”