MSE Graduate Research Seminar—B. Miljkovic and H. J. Cho

April 13, 2017 @ 12:00 pm – 2:00 pm
WB 130
184 College St
Toronto, ON M5S 3E4

Development of a monitoring system for electrochemically-produced hydroxyl radicals

Presenter: Bojan Miljkovic (Ph.D. Candidate)
Supervisor: H. Ruda

Untreated wastewater continues to be released by modern industrial processes, polluting water systems with chemicals ranging from dyes to pharmaceuticals. These pollutants can be broken down by introducing highly oxidizing agents such as ozone, hydrogen peroxide, and hydroxyl radicals. Electrochemical wastewater treatment harnesses the high oxidation potential of hydroxyl radicals through the use of anode materials with sufficiently high oxygen evolution potentials (OEP). However, due to their high reactivity and short lifetimes, hydroxyl radicals are difficult to detect and require trapping with a probe molecule. These probe molecules are hydroxylated by the radicals produced during electrolysis resulting in a fluorescent product that can then be detected. A monitoring system for the detection of electrochemical hydroxyl radical production is presented as a means to observe reaction kinetics as a function of anode material, such as low OEP iridum oxide and high OEP doped tin oxide. Pollutant removal capabilities of these materials were tested by treatment of simulated wastewater containing phenol in order to correlate the results obtained from fluorescence spectroscopy.

Thermal Transport Properties of Electrodeposited Metal/Diamond Composite Materials

Presenter: Hai Jun Cho (Ph.D. Candidate)
Supervisor: U. Erb

This research is concerned with electrodeposited metal-diamond composite materials for heat sinks in the thermal management of high powered electronic devices. Using nickel-diamond as a prototype material the effects of grain size of the nickel matrix and diamond particle volume fraction were studied first. It was shown that by using a grain size of 43 nm and 66 µm sized diamond particles the thermal conductivity increased by 160% over the conductivity of pure nickel. Surprisingly, the same diamond particle size decreased the thermal conductivity when the nickel matrix was replaced with copper matrix for commercially more viable heat sinks. It will be shown that this can be explained on the basis of the effective thermal conductivity of diamond particles in composites relative to the thermal conductivity of the metal matrix. For the case of copper larger diamond particles are required to show a positive effect and increase the thermal conductivity of Cu-diamond composites over the value for pure copper.

Thursday, April 13, 2017 | 12:00 p.m. | WB 130

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