Estimating the Spreading Rates of Hazardous Materials on Unmodified Cellulose Filter Paper: Implications on Risk Assessment of Transporting Hazardous Materials

Abstract

The transportation of hazardous materials (HAZMAT) has been challenging over the years due to the inherent environmental and associated health risks. To fully understand the potential environmental impacts of HAZMAT accidents, estimating the potential spread for various HAZMATs is needed for a complete risk assessment. We conducted diffusion tests on porous filter paper for four HAZMAT compounds —methanol, ethanol, hydrochloric acid, and sodium hydroxide—on unmodified α-cellulose filter paper using conservative (nonreacting) dye tracers. We determined spread area, time of diffusion, porosity, and retention factors among other properties. The analytes showed that the chemical dispersion properties are distinctly different. For example, the range of retention factors of ionic solutions, although similar for methanol and ethanol, was significantly different for hydrochloric acid and sodium hydroxide. Temperature also has an impact on dispersion properties. The diffusion area for sodium hydroxide increased in temperature while its viscosity decreased. All other analytes diffusion increased with increasing temperature. An analytical solution using an amplitude diffusing mass model was used to estimate the diffusion coefficients of each analyte. Using the derived diffusion coefficient values, a maximum spread model using Fick’s second law was used to countercheck the maximum spread rates. In this study, we were able to derive maximum spread areas, indicating that a finite element model developed was able to replicate analyte spread at various temperature settings.