| 摘要 |
Toxic substances such as heavy metals are extracted from a medium using a sorbent composition. The composition is derived by sulfidation of red mud, which contains hydrated ferric oxides derived from the Bayer processing of bauxitic ores. Exemplary sulfidizing compounds are H 2 S, Na 2 S, K 2 S, (NH 4 ) 2 S, CaS x . The sulfur content typically is from about 0.2 to about 10% above the residual sulfur in the red mud. The sulfidized red mud is effective for sorbing some contaminants, such as mercury, which are not effectively sorbed by red mud. Conversely, red mud is effective for sorbing other contaminants, such as arsenic, which are not effectively sorbed by sulfidized red mud. Thus, some aspects of the invention utilize combinations of red mud and sulfidized red mud, which potentially can allow for the extraction of a wider range of contaminants. |
