Date of Award

Summer 2019

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Engineering

Committee Chair

Xufei Yang

First Advisor

Katherine Zodrow

Second Advisor

Liping Jiang

Third Advisor

Kim Snodgrass

Abstract

Electrokinetic remediation was accessed as a viable remediation technology for heavy metal contamination modeled after contamination present in Butte, MT caused by over a century of hard rock mining. The remediation technology was assessed at a laboratory scale using copper sulfate (CuSO4) as a model compound of mine tailing contamination, and an artificial soil to control for variables outside the scope of work. This thesis designed a laboratory scale experiment that produced consistent results and could be easily repeated. The system design also included a method for managing the waste material produced during experiments. Following the experimental design, this thesis evaluated the effect of several complexing agents on the transport rates of copper ions (Cu2+) in an electrokinetic system. Chloride (Cl-), bromide (Br-), ammonia (NH3), and ethylenediaminetetraacetic acid (EDTA) were used to complex copper ions, originally hydrated with water molecules. A total of 17 experiments were conducted during this thesis. Transport rates were calculated using real-time direct current measurements and inductively coupled plasma (ICP) analysis data. Previous studies suggested that the transport of the complexed ions was directly proportional to their complex radii. However, in this thesis, the size to transport rate relationship was not observed, and depletion/enrichment rates varied within experiments. Depletion and enrichment were defined as the percent change of copper mass in the electrode compartment from initial to final conditions. The largest enrichment rates were observed in the CuSO4 experiments at 0.082 mg s-1 while the largest depletion rates were observed in the EDTA experiments at 0.093 mg s-1. Changes in pH caused by the electrolysis of the electrodes is a likely underlying factor behind the mixed results, as these pH changes play a large role in altering the solubility of the metals in solution.

Comments

A thesis submitted in partial fulfillment of the requirements for the degree of Masters of Science: Environmental Engineering

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