This paper describes experimental results of equilibrium partitioning of several significant paint solvents and formaldehyde between air and water to quantify the potential for capturing and retaining the constituents in spraybooth scrubber water during automotive painting. The compounds
studied are toluene, n-butanol, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, and n-methyl-2-pyrrolidinone. A set of field data collected at a Ford Motor Company assembly plant
was also analyzed to determine whether data were consistent with the equilibrium phenomenon. The primary findings include: (a) There were more than six orders of magnitude difference in the Henry's law constants among the solvents studied. A solvent with a smaller constant is less easily stripped
from water. The Henry's law constants decrease in the following order: toluene and xylenes methyl ethyl ketone n-butanol butyl cellosolve acetate butyl cellosolve formaldehyde butyl carbitol n-methyl-2-pyrrolidinone. (b) Field data showed accumulation of n-methyl-2-pyrrolidinone
and stable concentrations of butyl carbitol, butyl cellosolve, and n-butanol in the paint-sludge pit water during a 2-month period. Stable concentrations indicate a continuous, balanced capture and stripping of the solvents. Data were consistent with measured Henry's law constants.
(c) The low Henry's law constant for formaldehyde is the result of the fact that it is hydrated when dissolved in water.
Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.