The development and evaluation of removable thin film coating technology for the abatement and mitigation of hazardous particulates in an occupational setting.

摘要

This dissertation evaluates a new decontamination technique for the mitigation and abatement of hazardous particulates. Currently, traditional decontamination methods, such as, the wet method and the use of vacuums and brooms are used to clean facilities and equipment. These are time consuming, resulting in prolong exposure to the contaminant and may generate airborne hazards. A new technique using removable thin film coating technology, a loosely adhered paint-like coating was tested as a viable alternative to traditional methods. Tests conducted at three different sites on different hazardous metals resulted in reducing the initial levels of the metals by 90 percent and had an average reduction of one magnitude after one application of the coating. The paired t-tests performed for each metal demonstrated that there was a statistically significant reduction in concentration after the use of the removable thin film coating: lead (p = 0.03), beryllium (p = 0.05) aluminum (p = 0.006), iron (p = 0.0001), and copper (p = 0.004). A Kendall Tau correlation coefficient confirmed that there was a positive correlation between the initial levels of contamination and the removal efficiency for all of the metals at each of the three sites.;Qualitative tests demonstrated that the coating reduced the amount of visible luminescent dust from various surfaces and that it worked well as a preventative method, protecting clean areas from becoming contaminated. These tests also exposed a limitation of the coating. It could not migrate into the minute scratches on the surface substrates. The use of a scanning electron microscope (SEM) and calibrated carbon dust supported the previous findings with a statistically significant (p = 0.00007) removal of carbon dust from the surfaces substrates. The SEM also revealed that wherever there were large clusters of carbon dust, the coating would tear and remain on the sample surface.;To eliminate these issues two different methods were tested. First, Kevlar(TM) fibers were added to improve the strength of the coating. Next, the use of an engineered textile, saturated with the coating, was tested. This appeared to eliminate the issue of removing contaminants from minute surface scratches and improved the removal process of the coating.