자료유형  

 학위논문

Control Number  

0016935404

International Standard Book Number  

9798380723961

Dewey Decimal Classification Number  

600

Main Entry-Personal Name  

Sultana, Ruhi.

Publication, Distribution, etc. (Imprint  

[S.l.] : The Pennsylvania State University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(152 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

General Note  

Advisor: Janik, Mike.

Dissertation Note  

Thesis (Ph.D.)--The Pennsylvania State University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약The recovery of phosphate from wastewater sources in the form of inorganic magnesium ammonium phosphate hexahydrate (or struvite) precipitates (or struvite) is an advantageous choice, particularly because it can be used as a slow-release fertilizer in agriculture. Section 1 of this dissertation provides an introduction and review of the electrochemical recovery of P using a sacrificial magnesium (Mg) anode via hydrolysis in a bench scale electrochemical reactor. As a result of corrosion, Mg2+ is electrochemically released from the anode and struvite precipitates through an interaction between Mg2+ and the ammonium and phosphate ions in the solution. A 316 stainless steel cathode provides the site for water reduction to dihydrogen (H2) and hydroxyl ions (OH- ) and oxygen reduction to water.In section 2, a scaled-up batch electrochemical reactor has been designed to examine how the performance of the reactor changed over successive batches as anode degradation and fouling decreased struvite yield by 52% and increased energy consumption by 77%. This is because Mg oxidation, when exposed to phosphate solution, resulted in a dynamic change on the anode surface (i.e., corrosion and struvite build up) which likely influenced the reactor performance.Controlling electrode fouling and enhancing Mg dissolution for struvite precipitation requires an investigation into corrosion mechanisms at the electrode surface. Therefore, sections 3 and 4 present a mechanistic description of electrode passivation and struvite formation in presence of chloride ions (0-1500 mM) and dynamic voltage changes to the electrochemical reactor at frequencies 0.1-100 Hz. An insight into the process parameters affecting struvite precipitation, including solution pH, Mg overpotential, and chloride concentration, guided experiment design and simulation of product distribution analysis using Visual Minteq 3.1 software suggested optimum electrochemical struvite production in the pH range 8-10.In section 5, a first-of-its-kind electrochemical struvite precipitation was reported in an electrochemical packed bed reactor with pure Mg beads as the packing material. While the lower costs of the beads, reduced the overall cost of operating the reactor, the smaller surface area ensured a larger specific area and a higher yield. In a synthetic solution of ammonium dihydrogen phosphate, the performance of the electrochemical precipitation column was studied by varying the applied current, feed flow rate, and Mg bead diameter. The system achieved 60% phosphate removal as struvite at 50 mA, 0.6 L m-1 , with 5-6 mm bead size. The experimental outcomes assisted in comprehending the variables that affected struvite recovery in a flow-based reactor design as well as the difficulties associated with switching from a batch reactor to a flow reactor system.A summary of the key findings of this study have been presented in section 6, along with a list of future research areas that are to be explored.

Subject Added Entry-Topical Term  

Manures.

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Feeds.

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Electrodes.

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Water pollution.

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Urine.

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Decomposition.

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Crystallization.

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Phosphates.

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Effluents.

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Energy consumption.

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Nitrogen.

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Aqueous solutions.

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Eutrophication.

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Agriculture.

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Membrane separation.

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Oxidation.

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Watersheds.

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Fertilizers.

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Phase transitions.

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Corrosion potential.

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Magnesium.

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Ammonia.

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Salinity.

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Nutrient removal.

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Agricultural engineering.

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Environmental engineering.

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Physical chemistry.

Index Term-Uncontrolled  

Phosphate

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Hydroxyl ions

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Struvite precipitation

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Electrochemical precipitation

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Flow reactor system

Added Entry-Corporate Name  

The Pennsylvania State University.

Host Item Entry  

Dissertations Abstracts International. 85-05B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:639564