Date of Award

2020

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Chemical Engineering (MS)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Timothy Eisele

Advisor 2

Andre Da Costa

Committee Member 1

Gerard Caneba

Committee Member 2

David Shonnard

Abstract

This research study first reviewed challenges of conventional and membrane separation systems for water treatment. Though membrane separation systems appeared superior to the conventional counterparts for water and wastewater treatment, wider applications of membrane systems have been limited by some factors, most notably is membrane fouling. Experimental studies were therefore conducted to achieve the goal of this research, which is to investigate how feed properties affect fouling of ultrafiltration (UF) membranes by colloids.

Feed salinity, pH, and nanoparticle concentration were the variables studied to unravel how different UF membranes are fouled by model silica colloids (with average diameter of 25nm). These variables were varied across levels that have practical importance. Results obtained show that ultrafiltration gave high separation efficiency to the nanoparticles with rejection in most cases. Electrostatic interactions in the system impacted by changes in feed pH and salinity were found to affect the ultrafiltration of the model water samples. It was also observed that increase in silica colloid concentration increases rate of permeate flux decline for all the membranes used. When experimental data were fitted with the blocking laws, it was observed that no single law adequately described all the experimental results. However, cake filtration model sufficiently described most of the results.

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