Evaluating the efficacy of PAC and water parameters to remove trace organics

Multivariable regression modeling was used to evaluate the efficacy of commonly used powdered activated carbon (PAC) and water parameters for selecting a commercial PAC to remove trace organic contaminants from natural waters. Trace concentrations of radiolabeled methylisoborneol (MIB) and atrazine were spiked into natural waters, including surface and groundwater sources, and treated with PACs at varying contact times and PAC doses. A rigorous selection criterion was applied to the regression modeling effort to optimize the R2-adjusted, hypothesis test the significance and prevent multicollinearity of regression coefficients. The results indicated that MIB and atrazine removal were affected by the same PAC parameters: tannin value and phenol value or trace capacity number in liquid phase (TCNL). The TCNL and phenol value were strongly correlated parameters. Similarly, ultraviolet absorbance at 254 nm and specific ultraviolet absorbance at 254 nm influenced performance and could be interchanged. Surface area and iodine number did not appear to be significant in the regression analysis.