Show simple item record

dc.contributor.advisorSaikaly, Pascal
dc.contributor.authorAlQahtani, Manal Faisal
dc.date.accessioned2019-12-02T12:40:38Z
dc.date.available2019-12-02T12:40:38Z
dc.date.issued2019-11
dc.identifier.doi10.25781/KAUST-EH45U
dc.identifier.urihttp://hdl.handle.net/10754/660362
dc.description.abstractMicrobial electrosynthesis (MES) is an emerging biotechnology platform for the conversion of CO2 feedstocks into value-added chemical commodities. In MES, microbial catalysts use the cathode (electrons/ H2) as a sole source of energy for the reduction of CO2. Integrating MES technology with renewable energy sources, such as solar power, to convert CO2 to storable chemicals is an example of a perfect circular economy and a sustainable climate change mitigation strategy. However, many knowledge gaps need to be addressed to scale-up MES as an economically viable chemical production process. Therefore, different in-depth approaches were tested in this dissertation by optimizing the cathode architecture and exploring the saline application to enhance MES performance. A balance between various bio-physicochemical phenomena at the MES cathode, i.e., the three-phase interface between CO2 gas, cathodic-biofilm, and electrolyte, is desirable for efficient microbial electrochemical CO2 capture and utilization. To address this problem, this thesis investigated alternatives to the benchmark carbonbased plane cathode by applying a dual-functioning (cathode as well as a CO2 gas-transfer membrane) electrode architecture on MES performance. High Faradaic efficiencies for CO2 reduction were achieved with this novel cathode architecture. This hollow-fiber electrode architecture was also applied to MES operation in saline conditions (i.e., Saline-MES). Because seawater potentially acts as an endless source of saline electrolyte, and its high electrical conductivity useful to minimize the concentration overpotential losses occurs in MES. However, exploring robust halophilic microbial catalysts with high selectivity towards CO2 reduction to the desired end product(s) is necessary to develop the saline-MES process. Therefore, this thesis investigated natural saline habitats with hyper (Red sea brine pool) and moderate salinity (mangrove and salt marsh sediment) as a source of inoculum. Emphasis was placed on improving new knowledge in the direction of halophilic CO2 reducing communities enrichment using cathode selective pressure in the saline-MES. The fundamental insights demonstrated in this dissertation are useful for further development of MES technology, to bring MES one step closer to full-scale applications, for overcoming the bottlenecks associated with reactor scaling-up related to cathode architecture, strategies for the enrichment of halophilic CO2 reducing microbial communities, and saline-MES process optimization.
dc.language.isoen
dc.subjectCO2 Conversion
dc.subjectMicrobial electrosynthesis
dc.subjectDual Function Macroporous Hollow Fiber (DFMHF)
dc.subjectAcetate and methane production
dc.subjectHomoacetogens and methanogens
dc.subjectHalophilic CO2 reducing communities
dc.titleCarbon Dioxide Conversion to Value-Added Products using Microbial Electrosynthesis Cell
dc.typeDissertation
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.rights.embargodate2020-12-01
thesis.degree.grantorKing Abdullah University of Science and Technology
dc.contributor.committeememberGhaffour, NorEddine
dc.contributor.committeememberMerzaban, Jasmeen
dc.contributor.committeememberKaturi, Krishna
dc.contributor.committeememberPant, Deepak
thesis.degree.disciplineEnvironmental Science and Engineering
thesis.degree.nameDoctor of Philosophy
dc.rights.accessrightsAt the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation will become available to the public after the expiration of the embargo on 2020-12-01.
kaust.request.doiyes


Files in this item

Thumbnail
Name:
Manal Faisal Alqahtani_Ph.D. Dissertation.pdf
Size:
18.00Mb
Format:
PDF
Description:
PhD Dissertation - Final Version
Embargo End Date:
2020-12-01

This item appears in the following Collection(s)

Show simple item record