Development of anti-fouling membranes using hydrophilic negatively charged graphene coatings

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Canada's oil sands deposit extends over 142,200 km2 in northern Alberta and occurs near surface or deep in the ground. With approximately 168 billion barrels of proven reserves, this deposit is the third largest proven crude oil reserve in the world. Recovery of oil sands, however, relies heavily on water, and between surface mining and in situ recovery Alberta's water resources are being stretched. In an effort to reduce demand on these resources, oil sands operators recycle 80-95 per cent of the water and use saline water where possible. Given the projected expansion and the water to oil ratio needed to process/recover the bitumen, minimizing makeup water through effective water recycling is essential for the sustainability of oil sands operations and, hence, the Canadian economy. Produced water (PW) treatment, on the other hand, is a very challenging task, since in addition to dissolved organic matter (DOM), PW contains suspended solids, colloidal and dissolved silica, soluble salts, dissolved solids (TDS), etc. Together these contaminants qualify PW as chemically aggressive environment and mandate a combination of unit operations/processes to recycle it. Most recently, membrane filtration has been identified as a potentially viable one-step treatment technique with capabilities of functioning as mobile units. However, membranes suffer from susceptibility to the harsh chemical environment and more importantly to the severe fouling associated with PW. It is not until anti-fouling membranes have been developed, will membrane filtration succeed as an ideal treatment technique for PW. Graphene Leaders Canada (GLC) has developed a novel process to produce high quality graphene sheets using a chemical exfoliation process. When applied to membranes, graphene/graphene oxides may alleviate fouling to a great extent by virtue of their hydrophilic nature and ability to be polarized to carry negative charges. If the technology of coating membranes with graphene becomes available, GLC would have a significant competitive advantage and would lead effort toward Canada's PW treatment.