Graduation Year

2022

Document Type

Thesis

Degree

M.S.E.V.

Degree Name

MS in Environmental Engr. (M.S.E.V.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Katherine Alfredo, Ph.D.

Committee Member

Christopher Alexander, Ph.D.

Committee Member

Qiong Zhang, Ph.D.

Keywords

drinking water, electrode fouling, electrolysis, pitting, potentiostatic

Abstract

Electrocoagulation (EC) is a sustainable water treatment process involving the generation of coagulants on-site through the application of a voltage on metal (usually aluminum or iron alloys). The factors that impact EC system performance have been well researched, however further research is needed on the factors that impact anodic dissolution of aluminum electrodes, especially when the technology is transferred to full-scale applications. Electrode fouling is one of the factors that can impact dissolution of the anode during EC due to the formation of a protective oxide/hydroxide layer on the electrode surface. Previous studies have addressed electrode fouling by reversing polarity, however results have been mixed or obtained for shorter timeframes that might not be applicable to full-scale EC systems. In addition, discussion regarding pitting patterns and aluminum production during EC water treatment is limited. In this study, the effect of switching polarity and pitting patterns (pit size, type, and location) on aluminum production and current density were evaluated in a continuously mixed EC batch reactor. The corrosion timeline and the effect of switching polarity versus normal operation on pitting trends over the expected life of the aluminum plates were also evaluated. The results showed that system performance was superior over time when direct polarity was used, due to sustained higher aluminum production and correlation between aluminum and current. Therefore, the use of direct polarity was recommended over the use of reverse polarity within the experimental parameters implemented.

Download

Share

COinS