Biosorbents have emerged as an alternative to remove organic contaminants because they are natural products with a high availability, low cost, biodegradability, and good sorption capacity. The Mandacaru (Cereus jamacaru DC) was investigated as sorbent of diesel, and compared with the Mandacaru modified with microemulsions. The sorbents were also submitted to a physycal-chemical characterization for FT-IR, TG/DTG, MEV and CHN-O. The granulometry range 500-150 µm of the Mandacaru particulate, this was the granulometry range chosen as the standard one, being used in the modification and sorption tests. The unclassified Mandacaru presented a medium sorption capacity of the diesel oil of 1.61 g g-1. Whereas the Mandacaru modified with a microemulsion comprised of direct micelles (oil/water) showed a remarkable increase in the sorption capacity of 80-111% (3,08 to 3,54 g g-1).