Differences between the use of ferric sulphate and ferric chloride on biodesulfurization of a large coal particle

espanolSe evaluaron tres fuentes de hierro (FeSO4, Fe2(SO4)3 y FeCl3) a diferentes concentraciones (150, 700 y 1250 mg Fe/L) en procesos de biodesulfurizacion de un carbon con tamano de particula grueso, utilizando un consorcio de Acidithiobacillus ferrooxidans (ATCC 23270) and Acidithiobacillus thiooxidans (ATCC 15494). Al usar 150 mg Fe2+/L (FeSO4), luego de 12 dias se obtuvo 31.14% de pirita oxidada. Al reemplazar FeSO4 por Fe2(SO4)3, la oxidacion mejoro en un 21.16%. Aunque los ensayos con las mayores concentraciones de sulfatos obtuvieron un resultado similar, al utilizar Fe2(SO4)3 permitio mejor remocion de sulfatos del carbon. Lo anterior sugiere que basta con utilizar la menor concentracion de Fe2(SO4)3 para mejorar el indice de oxidacion de pirita y evitar formacion de precipitados. Por otra parte, los ensayos con FeCl3 tuvieron una disminucion en la tasa de biooxidacion, indicando a priori, que los microorganismos no fueron capaces de adaptarse adecuadamente a los iones Cl-. EnglishThree iron sources (FeSO4, Fe2(SO4)3 and FeCl3) at different concentrations (150, 700 and 1250 mg Fe/L) were evaluated on large coal particle biodesulfurization processes at Erlenmeyer level. A consortium of Acidithiobacillus ferrooxidans (ATCC 23270) and Acidithiobacillus thiooxidans (ATCC 15494) was used in all the assays. By using 150 mg Fe2+/L (from FeSO4), pyrite biooxidation was 31.14% after 12 days. When Fe2(SO4)3 replaced FeSO4, oxidation improved by 21.16%. The assays using the highest concentrations of sulphate sources also obtained the same increase. However, Fe2(SO4)3 assays had a better sulphate removal from coal. This suggests that using the smallest concentration of Fe2(SO4)3 is a good alternative to boost the pyrite oxidation rate and avoid the formation of precipitates. Additionally, biooxidation in the FeCl3 assays decreased, indicating, a priori, that the microorganisms were not able to adapt properly to Cl- ions.