Title

Mobility enhancement of manganese dioxide produced during in-situ chemical oxidation of TCE by potassium permanganate using sodium polyphosphate.

Date of Award

2005

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

Keywords

Engineering, Environmental.

Rights

CC BY-NC-ND 4.0

Abstract

MnO2 is a product of in-situ oxidation of trichloroethylene (TCE) by KMnO4. This species tends to precipitate and hinder the oxidation process thereby reducing the treatment efficiency in more than one way. The main objective of this research was to enhance the mobility of MnO 2 precipitates using sequestration technique. A one dimensional column was designed to study the effect of sodium polyphosphate addition to the reaction solution containing KMnO4. The solution was injected to the silica sand artificially contaminated by WE and the mass removal rates were studied against the removal rates when no polyphosphate was added into the reaction solution. TCE was added to polyphosphate and KMnO4 solution in vial experiments to confirm the stabilization of MnO2 precipitates in the presence of polyphosphate. Reaction solutions contained varying concentrations of KMnO4 (500, 1000 and 2000 mg/L) and varying mass ratios of polyphosphate w.r.t. KMnO4 (1 to 8). Optimum conditions w.r.t KMnO4 and polyphosphate (mass ratio 1:4 at 1000 mg/L of KMnO4) were generated and used in column experiments. It was observed that dissolution rate and consequently overall mass removal rate was enhanced in column experiments when in-situ oxidation took place in the presence of polyphosphate. This was probably because of sequestration of MnO2 by polyphosphate which rendered WE more accessible to treatment. However, there was still some precipitation observed in the column when polyphosphate was added contrary to expectations from vial experiments results. Ionic strength of the solution in which reaction/precipitation/stabilization took place, was studied briefly during the vial experiments and higher ionic strength (>0.05 M) seemed to affect the stabilization adversely. Reaction kinetics experiments were conducted to estimate the effect of addition of polyphosphate on oxidation rate. It was observed that this addition did not substantially affect the kinetic rate of reaction.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .S73. Source: Masters Abstracts International, Volume: 44-01, page: 0506. Thesis (M.A.Sc.)--University of Windsor (Canada), 2005.