This thesis describes the preparation, optimization, functionalization, and characterization of activated carbon materials sourced from a petroleum coke feedstock for the tailored removal of heavy metal species in contaminated waters. The goal of this work is to develop an understanding of the mechanisms that drive adsorption of heavy metals onto activated carbon surfaces. By determining the mechanisms that drive adsorption, activated carbon materials can be modified to increase the efficiency of the adsorption process. The novelty of this work comes from the use, modification, and functionalization of activated carbon derived from petroleum coke, a waste by-product of the oil-sands extraction process, a source not prevalent in current literature. The novelty also comes from the determination of the methods by which heavy metals are adsorbed onto the given adsorbate as literature does not focus on the mechanisms themselves. The work presented sheds light on the specific adsorption mechanisms, with the aim of elucidating how a given material's surface can be enhanced to target a specific analyte. This work focused on the use of microwave plasma atomic emission spectroscopy (MP-AES), x-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller theory (BET) to obtain the necessary data required for the determination of adsorption mechanisms, adsorption capacities, and surface characterization of the materials. MP-AES is used for the determination of the adsorption capacity of the materials produced. Surface characterization of the materials was done using XPS, and surface area and pore size distributions were determined using BET for surface area determination and nitrogen adsorption measurements following density functional theory for pore size distribution determination. XPS of the activated carbon post-chromium and post-arsenic adsorption show a reduction of the metals from chromium (VI) to chromium (III) and from arsenic (V) to arsenic (III). By increasing the amount of hydroxyl functional groups on the AC surface through a simple thermal-treatment, the chromium adsorption was increased from 17.0 mg/g to 22.4 mg/g. By loading a reducing agent onto the activated carbon surface, an increased number of potential binding sites for the arsenic are loaded onto the AC surface and the adsorption of arsenic increased from 8.1% to 51%.
Author Keywords: Activated Carbon, Adsorption, Adsorption Mechanisms, Arsenic, Chromium, Petroleum Coke