Improved methods for carbon adsorption studies for water and wastewater treatment

Abstract

An improved method was developed to rank activated carbon in removing organic water pollutants. The simple and standardized evaluation method uses a set of four adsorptive capacity indicators: phenol, iodine, methylene blue, and tannic acid numbers; those four indicator compounds were selected because they cover the molecular size range of most organic water pollutants. An improved microcolumn rapid breakthrough (MCRB) test method was developed from the existing HPMC (high-pressure minicolumn) and RSSCT (rapid small-scale column test) methods by simplifying the experimental procedure and using readily available low-cost pump, sampler, piping, and fittings. This method can be practiced in an ordinary environmental laboratory to select the best carbon, to verify the treatment effectiveness, and to estimate the adsorption treatment cost based on the observed capacity utilization rate for carbon in the adsorber without the problems often encountered with using small and mini traditional columns. The benefits ofthe four-parameter carbon selection method and the MCRB method were demonstrated by adsorption isotherm and breakthrough data for several indicator compounds and organic water pollutants. These improved methods will enable efficient carbon adsorption studies necessary for more applications of carbon adsorption technology in water and wastewater treatment.