Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Professor Madhumita Ray

2nd Supervisor

Professor Chunbao (Charles) Xu

Abstract

Cost effective regeneration of spent adsorbent is crucial for large scale application of adsorption as a viable separation process. While adsorption studies are abundant in literature, systematic and comprehensive regeneration studies are seldom reported in open literature. A proprietary activated carbon from petroleum coke was used for the removal of model naphthenic acids (NAs) and organic compounds from oil sands process-affected water (OSPW). A systematic and comprehensive study was conducted to regenerate the adsorbents. Methanol with aqueous NaOH (pH adjusted to around 12) was applied to regenerate the spent commercially available granular activated carbon (GAC) and activated petroleum-coke (APC). Optimization of solvent volume, solvent pH, regeneration time, and agitation speed was evaluated in preliminary batch experiments. Higher adsorption capacity and regeneration efficiency were achieved for APC due to higher mesoporous surface area during the treatment of two model compounds (2-naphthoic acid and diphenylacetic acid) and NAs rich OSPW than that of the GAC. Thereafter, the optimum regeneration scheme was applied in continuous column operations for recycling the adsorbents. Although, the bed adsorption capacity decreased dramatically after first cycle, the capacity could be stabilized after 2 repeated adsorption-desorption cycles. The regenerating solvent (methanol) was recovered effectively (maximum 90% recovery ratio) using vacuum distillation. Moreover, Na-salts of NA were recovered, which have some commercial applications. A desorption kinetics model was also developed which would be useful for future scaling up of the process.

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