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Investigating Water Treatment Procedures with a Focus on Novel Porous Silicon / CHIALUKA IKOKWU

Swansea University Author: CHIALUKA IKOKWU

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DOI (Published version): 10.23889/SUThesis.70853

Abstract

Membrane processes for seawater desalination offer solutions to global water challenges, but factors such as high energy consumption and membrane fouling limit their capacity to provide fresh water worldwide.This work investigated the use of nanofiltration to desalinate seawater, with specific refer...

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Published: Swansea 2025
Institution: Swansea University
Degree level: Master of Philosophy
Degree name: M.Phil
Supervisor: Guy, O.
URI: https://cronfa.swan.ac.uk/Record/cronfa70853
Abstract: Membrane processes for seawater desalination offer solutions to global water challenges, but factors such as high energy consumption and membrane fouling limit their capacity to provide fresh water worldwide.This work investigated the use of nanofiltration to desalinate seawater, with specific reference to the removal of monovalent and divalent ions. Nanofiltration was found capable of removing 85% of calcium and 93% of magnesium from seawater. However, one limitation of the process is its inability to effectively remove monovalent ions such as Na.Electrodialysis as a means of seawater desalination was also investigated in this study. It achieved over 90% ion exchange in seawater within 75 minutes of operation. However, it has high energy requirements and is unable to remove organics from seawater.Surface modification of the NF membrane with oxygen plasma was found to improve hydrophilicity and flux while trading off performance in rejection. Ammonia plasma treatment for 50 seconds showed hydrophobic recovery after some time.Metal-assisted etching was used to create pores in a silicon wafer. Filtration results showed that water was able to pass through these pores, presenting a new approach to water desalination.
Keywords: desalination, nanofiltration, silicon, electrodialysis, plasma surface modification, porous silicon membranes, ion rejection, membrane fouling
College: Faculty of Science and Engineering