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Journal of Nanomaterials
Volume 2013, Article ID 471210, 7 pages
Research Article

Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

1Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
2National Research Center, Dokki, Cairo, Egypt

Received 30 December 2012; Revised 1 February 2013; Accepted 6 March 2013

Academic Editor: Tianxi Liu

Copyright © 2013 Samia A. Kosa and Eman Z. Hegazy. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The processes used for the extraction of metals (Co, Mo, and Al) from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involve an intermediate, the structure of which was proposed. This proposed intermediate was confirmed through simulations. Moreover, the activities of the spent and the regenerated catalyst were examined in the cracking of toluene. The modification of the spent catalyst through the use of different iron oxide loadings improved the catalytic activity.