Factors affecting binding of chlorophenols to soil
Synthetic substituted phenols can become incorporated into soil organic matter by processes similar to natural humification. Biological, (enzyme-catalyzed), and abiotic, (mineral surface catalyzed), reactions have been implicated in these processes which result in the nonextractable binding of ph...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Others |
| Language: | en |
| Published: |
Virginia Tech
2014
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/10919/39390 http://scholar.lib.vt.edu/theses/available/etd-09192008-063010/ |
| Summary: | Synthetic substituted phenols can become incorporated into soil organic
matter by processes similar to natural humification. Biological, (enzyme-catalyzed),
and abiotic, (mineral surface catalyzed), reactions have been implicated in these
processes which result in the nonextractable binding of phenolic contaminants to
soil organic matter. Experiments conducted with phenol, 4-monochlorophenol
(MCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) indicated a
statistically significant difference in the degree of nonextractable binding in oxic and
anoxic environments. Soils were extracted with water and methylene chloride. The
extracted soils were combusted at 950°C and the 14C02 evolved was quantified
as a measure of the bound contaminant. The amount of 14C02 captured during
combustion of the soils indicated that approximately two times greater contaminant
binding occurred in the oxic atmosphere as compared to the anoxic atmosphere.
Autoclaving the soil resulted in a reduction in contaminant binding. Addition of
H202 increased MCP binding by 4.5 times. The nonextractable contaminant
appeared to consist of (i) a biologically coupled; (ii) an abiotically coupled; and (iii)
a desorbable, but diffusion-limited component. The initial aqueous concentration
of the contaminant appeared to have the greatest effect on the degree of
nonextractable binding. An empirical model was developed for predicting the extent of chlorophenol binding to soil as a function of the initial aqueous
concentration of the contaminant. Nearly 50% of the nonextractable 4-MCP was
bioavailable to inoculated microorganisms. === Ph. D. |
|---|