Predicting the capacity of powdered activated carbon for trace organic compounds in natural waters

The purpose of this research was to develop a simple method for predicting the powdered activated carbon (PAC) capacity for micropollutants in natural water. The herbicide atrazine and the odor-causing compound 2-methyl-isoborneol served as target compounds. Isotherm data from experiments conducted with a constant initial adsorbate concentration and varying adsorbent doses exhibited nonlinearity in both single- and multi-solute systems. However, at any given adsorbent dose, the PAC capacity for the micropollutant in multi-solute systems was directly proportional to the initial micropollutant concentration. Using the ideal adsorbed solution theory (IAST), an equation was derived that validated the experimentally observed direct proportionality between PAC capacity and initial micropollutant concentration at a given adsorbent dose. The results of this study show that the PAC dose to remove any amount of micropollutant from natural waters can be estimated without the use of mathematical models from a single isotherm experiment conducted in the natural water of interest, provided that the initial target compound concentration is sufficiently low.