Speciation and removal of selenium (IV, VI) from water and wastewaters based on dried activated sludge before determination by flame atomic absorption spectrometry

In recent decades, large amount of pollutants enter to the environment due to development of technology. Therefore it is necessary to use ecofriendly sorbent to eliminate pollutants. In this research, an dried activated sludge (DAS) was used to decrease Se(IV) pollutant and the effect of operating parameters such as solution pH, the amount of biosorbent, contact time, temperature and initial concentration of selenium were studied. Kinetic data was adjusted to the Langmuir and Freundlich kinetic equations. It was resulted that the Freundlich equation with a correlation coefficient of 0.9956 has the Best match to tetravalent selenium biosorption on DAS. The FT-IR results showed that the biosorption mechanism of selenium tetravalent metal ion on DAS is because of the existence of functional groups on the DAS surface can interact with Se(IV) ions. This study aims to investigate the biosorption capacity of the DAS for tetravalent selenium ions in aqueous solutions.