자료유형  

 학위논문

Control Number  

0017164811

International Standard Book Number  

9798346387442

Dewey Decimal Classification Number  

621.48

Main Entry-Personal Name  

Liu, Matthew Junjie.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

338 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-05, Section: A.

General Note  

Advisor: Tarpeh, William.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2024.

Summary, Etc.  

요약Managing the nitrogen cycle has been identified as one of 14 Grand Challenges for Engineering in the 21st century, as defined by the U.S. National Academy of Engineering. Indeed, the U.S. Environmental Protection Agency considers nitrogen pollution "one of the costliest, most difficult environmental problems we face in the 21stcentury." Humanity has profoundly skewed the natural throughput of the nitrogen cycle through Haber-Bosch ammonia synthesis, which outpaces nitrogen removal rates from wastewater. As a result, nitrogen pollution continues to accumulate in the environment, threatening global water security and human health. However, as global populations continue to grow, humanity will require more ammonia than it ever has before.Electrochemical nitrogen recovery from wastewaters offers an avenue for bringing balance back to the nitrogen cycle by directly recovering ammonia from wastewater nitrogen. Two forms of reactive nitrogen in particular compose the majority of nitrogen pollution in wastewaters: ammonia and nitrate. Targeting these two pollutants for ammonia recovery is a key focus of this dissertation. Whereas ammonia requires a selective separation from other wastewater constituents to be recovered as a pure product, nitrate requires selective reduction to ammonia prior to separation. Thus, the work in this dissertation explores techniques for achieving selective electrochemical separations and selective electrochemical reactions.In Chapter 2 explores the use of electrochemical stripping, a unit process combining electrodialysis and membrane stripping, for ammonium sulfate recovery from ammoniarich influent as a function of electrolyte temperature, gas permeable membrane, and influent concentration (30 to 3000 mg N/L). A mass transfer model for nitrogen movement between reactor chambers is developed to yield both descriptive and predictive insights into the effect of operating parameters on nitrogen recovery. The validation of electrochemical stripping as a platform for selectively separating ammonia forms a bedrock for the remainder of this dissertation.Chapters 3-5 consist of studies into electrochemical nitrate reduction to ammonia, with the idea that synthesized ammonia can be recovered with electrochemical stripping. Chapter 3 examines the use of titanium electrodes for nitrate reduction. Under the protic, reducing conditions of nitrate reduction, titanium forms titanium hydride, which possesses distinct physical, chemical, and electronic properties from titanium. The work in this chapter employs synchrotron X-ray characterization to study how different nitrate reduction conditions (applied potential, duration) impact the formation of near-surface titanium hydride, and the impact this altered surface structure may have on nitrate reduction performance. Chapters 4-5 explore the use of the homogeneous electrocatalyst Co(DIM), a cobalt-centered tetra-aza macrocycle, for selective nitrate reduction to ammonia. In Chapter 4, Co(DIM) is incorporated into electrochemical stripping to simultaneously treat nitrate-rich secondary effluent and ammonium-rich reverse osmosis brine. The work demonstrates successful separation of synthesized ammonia from the catalyst and treated water at performance metrics (energy consumption, recovery rate) that matched or outperformed state-of-the-art nitrogen recovery systems. Chapter 5 investigates the reaction mechanisms and kinetics of Co(DIM) through electroanalytical studies. It is shown that prior to nitrate conversion, Co(DIM) must free its axial sites through bromide dissociation coupled with electron transfer. The kinetics of nitrate conversion, including reaction rate constants, turnover frequencies, kinetic isotope effects, and activation parameters, are quantified to benchmark the performance of Co(DIM)-mediated nitrate reduction.

Subject Added Entry-Topical Term  

Reactors.

Subject Added Entry-Topical Term  

Nitrates.

Subject Added Entry-Topical Term  

Electrons.

Subject Added Entry-Topical Term  

Electrodes.

Subject Added Entry-Topical Term  

Water treatment.

Subject Added Entry-Topical Term  

Chemistry.

Subject Added Entry-Topical Term  

21st century.

Subject Added Entry-Topical Term  

Voltammetry.

Subject Added Entry-Topical Term  

Chemists.

Subject Added Entry-Topical Term  

Ammonia.

Subject Added Entry-Topical Term  

Catalysis.

Subject Added Entry-Topical Term  

Effluents.

Subject Added Entry-Topical Term  

Electrocatalysis.

Subject Added Entry-Topical Term  

Energy consumption.

Subject Added Entry-Topical Term  

Nitrogen.

Subject Added Entry-Topical Term  

Atomic physics.

Subject Added Entry-Topical Term  

Energy.

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Environmental engineering.

Subject Added Entry-Topical Term  

Industrial engineering.

Subject Added Entry-Topical Term  

Museum studies.

Subject Added Entry-Topical Term  

Engineering.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 86-05A.

Electronic Location and Access  

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Control Number  

joongbu:654301