Author Type

Graduate Student

Date of Award

Fall 12-1-2025

Document Type

Dissertation

Publication Status

Version of Record

Submission Date

December 2025

Department

Ocean and Mechanical Engineering

College Granting Degree

College of Engineering and Computer Science

Department Granting Degree

Ocean and Mechanical Engineering

Degree Name

Doctor of Philosophy (PhD)

Thesis/Dissertation Advisor [Chair]

Myeongsub Kim

Abstract

Carbon capture, utilization, and storage (CCUS) technology has emerged as a primary engineering pathway to mitigate global warming and climate instability. For carbon capture, amine-based absorption and stripping are widely used due to their high capture efficiency and retrofit compatibility. However, these systems generate toxic wastewater, consume large volumes of freshwater, and require significant regeneration energy. For carbon utilization and storage, deep saline aquifers and carbon dioxide (CO2)- assisted enhanced oil recovery (EOR) have been proven to be feasible options at the industrial scale; however, concerns remain about long-term subsurface storage integrity and limited efficiency in carbonate reservoirs containing more than 60% oil. Hence, there is a need for an environmentally aligned and economically viable solution that can achieve long-term, sustainable CCUS. This dissertation proposes a waste-derived seawater-based approach that couples CO2 capture, utilization, and storage. The approach utilizes the most artificially abundant waste solid, waste concrete, with the most naturally abundant aqueous medium, seawater. Waste concrete increases seawater’s alkalinity and supplies additional calcium ions, which eliminates the need for freshwater while enhancing seawater’s CO2 dissolution and stabilization capacity. Through well-controlled microfluidic investigations, we quantified that waste concrete can favorably alter seawater’s chemistry, with an enhanced dissolution coefficient of 530 μm2/s to 835 μm2/s, resulting in a 4-fold increase in dissolved inorganic carbon from 0.034 M to 0.13 M, equivalent to a 400% increase in carbon capture. To utilize carbonated seawater containing captured CO2, a novel carbonate reservoir-mimicking microfluidic platform was fabricated from polydimethylsiloxane mixed with calcium carbonate. Sessile droplet tests confirmed strong oil-wet characteristics with contact angles of 138.6° in deionized water and 130.9° in seawater. Flooding experiments demonstrated that the carbonated seawater-concrete solution recovered 30.4% of the original oil in a random porous network, compared to 39.9% of the conventional toxic chemical flood. These results demonstrate that concrete-activated seawater can increase CO₂ capture, convert it into a mineral form, and function as a displacement fluid for enhanced oil recovery within a single integrated system. Most importantly, the proposed method replaces conventional, costly chemicals or freshwater with a greener and cost-effective CCUS medium. The findings provide a basis for further study on economic feasibility, scale-up, and long-term application of the proposed approach for CCUS.

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