A study has been carried out on the modification of surface tension in aqueous solutions of the collector sodium 1-dodecanesulfonate, at temperature of 293.15 K and pH between 4 and 10. The results of this study show that the surface tension varies very slightly when the pH in the medium of flotation bath is changed. The critical micelle concentration has been identified, and certain thermodynamic quantities associated with the adsorption of sodium 1-dodecanesulfonate in the solution-air interface were also obtained. Moreover, the values for the molecular limiting area range between (38 to 49) angstrom(2) per molecule and standard adsorption energy between (-29.00 to -29.61) kJ(.)mol(-1), at pH between 4 and 10.