Effect of manganese concentration and aeration time in the removal of sulfides from the effluent in the furling stage of the tanning process

Abstract

The effluents generated in the peeling stage present the highest pollutant load of the total effluent from the tanning process with presence of sulfides, organic matter, this is due to the inclusion of additive such as (sodium sulfide (Na2S) and slaked lime (Ca(OH2)) characteristic of this stage. For this reason, in the present study the oxidation-aeration method was used through the use of manganese in the form of MnO2 (IV) and MnCl2; in order to demonstrate the effect of the manganese concentration at 0,5 ; 1 and 1,5% and the aeration time of 4 and 8 hours with an aeration flow of 0,2 l/min in the removal of sulfides from the effluent at the stage of growth of the tanning process. Through the combination of aeration and the use of MnO2 and MnCl2, the highest sulfur removal efficiency is obtained at a concentration of 1,5% (mass percentage of the solution) of MnO2 and MnCl2 and an aeration time of 8 hours. The removal of 83,1 and 98% of sulfides was achieved, this being the last one with the highest efficiency.