Date of Graduation
Bachelor of Science in Chemical Engineering
Hestekin, Jamie A.
The world has acknowledged climate change as a global crisis that demands considerable attention, with one of the largest culprit being carbon emissions from industrial processing and power generation. While reduction in carbon emissions is the principal action towards mitigating the effects of climate change, scientists and engineers have given increased attention to alternative sources of energy as well as methods of carbon sequestration to coax traditional manufactory and industry into environmentally friendly and sustainable practices. One technology of this nature is the use of wafer-enhanced electrodeionization (WE-EDI) membranes to convert gaseous carbon dioxide (CO2) from industrial flue gas into aqueous bicarbonate (HCO3-) to be used in enriched media to feed and grow Chlamydomonas reinhardtii algae in a photobioreactor. Studies have shown that this species of algae experience enhanced and controlled growth with soluble HCO3- as the sole or as an additional carbon source to air. Algae photobioreactors can then conduct various coveted conversions and recycling, such as bioethanol and biodiesel from waste water sources. In the following investigations, low concentrations of bicarbonate addition to algae media, up to 0.1mM, show a slight increase in algae growth and stabilization after 14 days. Higher concentrations past 0.1mM seem to stunt growth and delay the stabilization phase. With regards to investigations on the WE-EDI, while the system can successfully carry out the c conversion, the system suffered consistent failures with internal leaking, in which one of the liquid chambers would mix with the other. The most notable area involves highly acidic solution in the dilute chamber leaking into the positive electrode rinse chamber. This internal leaking will cause long term damage to the system’s electrodes, which require buffer rinse solutions so as to prevent ion accumulation and corrosion. Regardless of this, carbon dioxide mix delivery tanks were also difficult to obtain, so investigation with gas delivery into the WE-EDI was mostly unavailable. Ultimately, this report enumerates efforts to operate a WE-EDI system of this nature, the techniques learned, and provides conjecture and research as to the feasibility of this technology. This research will aid efforts to increase the viability of sustainable algal processes in industry such as this, and will hopefully inspire more widespread investigation and application of efficient and profitable flue gas scrubbing of carbon emissions in order to combat their globally destructive effects.
electrodeionization, membrane, algae, bicarbonate, carbon, sequestration
Afrasiabi, K. (2018). Wafer Enhanced Electrodeionization for Conversion of CO2 into Bicarbonate Feed for Algae Cultured Photobioreactors. Chemical Engineering Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/cheguht/123