Removal of Manganese content from synthetic aqueous solution and groundwater using direct Sonolysis/Hybrid Sonolysis

This paper shows the results of laboratory scale tests for manganese removal from aqueous solutions
and groundwater by sonolysis. Ultrasonic cavitation phenomena lead to active radicals generation
able to transform soluble Mn (II) into insoluble species. The influence of initial manganese
concentration, sonolysis time, oxidant (H2O2) and catalyst doses (Fe) in case of hybrid sonolysis,
energy and amplitude of ultrasonic waves on manganese removal have been studied. Three categories
of ultrasonic test were performed for synthetic solutions: direct sonolysis (US), hybrid system US +
HO22
, Fenton sonolysis US + H2O2 + Fe. Based on preliminary results Fenton sonolysis was selected
for experimental with groundwater (280µg Mn/L, 180 µg Fe initial / 1200 µg Fe/L after addition of
ferrous sulfate, 12 mg C/L - dissolved organic carbon). Residual manganese concentration was 40µg
Mn/L, below the limit (50µg Mn/L) for drinking water. The real pollution matrix of groundwater
changes the optimal operational conditions significantly so, must be taking into consideration local
characteristics during the year.