Abstract
The aim of this work was to study the influence of ionic strength (IS) (with NaCl and Na2SO4) on the removal of As5+ by adsorbing colloid flotation (ACF), using as collector sodium dodecylsulfate (SDS). The morphology of the precipitate retained in the foam was analyzed by scanning electron microscopy (SEM/EDS).
The effect of an increase in the IS by adding NaCl proved to be insignificant on the As5+ removal by ACF. On the other hand, by adding SO4 2− ions, the same increase in IS resulted in a removal decrease of 62.2%. By introducing, however, 80 mg L−1 of Al3+ such deleterious effects from IS were minimized since an increase in As5+ floatability (37.7% without Al3+ and 76.5% with Al3+) was noticed.
Through SEM/EDS analyses, it was possible to observe that both morphology and composition of the precipitate produced in the solution and retained in the foam depend on the physico-chemical conditions of the system, i.e., on the species present in the solution.
ACKNOWLEDGMENTS
The authors gratefully acknowledge CAPES and FAPERJ for their financial support.