| Title: | The retrograde adsorption phenomenon at the onset of breakthrough and its quantitation: An experimental case study for gaseous toluene on activated carbon surface |
| Author(s): | Vikrant K; Kim KH; Szulejko JE; |
| Address: | "Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul, 04763, Republic of Korea. Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul, 04763, Republic of Korea. Electronic address: kkim61@hanyang.ac.kr" |
| DOI: | 10.1016/j.envres.2019.108737 |
| ISSN/ISBN: | 1096-0953 (Electronic) 0013-9351 (Linking) |
| Abstract: | "The adsorption dynamics of common solid sorbents against various pollutant species are yet poorly understood with respect to the retrograde phenomenon in which the relationship between breakthrough vs. pulled volume is characterized by an early unusual trend (initial increase followed by a decrease to a minimum) and by a normal trend of finally increasing to 100% (or equilibrium). If such trend is expressed in terms of the partition coefficient (PC), a reversed trend of adsorption processes becomes more evident. Retrograde has been previously observed in the initial breakthrough (<10%) isotherms in continuous flow gas-phase adsorption processes. However, retrograde has been neglected/overlooked and not discussed at all in the main stream literature even when it is explicitly observed from isotherm datasets. To properly describe the various aspects of such process, a stop-flow technique was developed to measure the adsorption isotherm of a model volatile organic compound (i.e., toluene in this study) onto a commercial low-cost sorbent (activated carbon: AC). Accordingly, a 10% breakthrough volume of 762?ª+L?ª+atm g(-1) (corresponding adsorption capacity of 142?ª+mg?ª+g(-1)) was determined (at an inlet stream 5?ª+Pa of toluene in 1?ª+atm of N(2) and 5?ª+mg of AC). This automated method was effective to generate a detailed breakthrough profile at high stream-flow rates (or high space velocities) to specifically detect the retrograde phenomenon at the breakthrough onset. This study offers a practical approach towards establishing an in-depth monitoring protocol for the rare retrograde phenomenon" |
| Keywords: | "*Absorption, Physicochemical Adsorption Charcoal/*chemistry Gases *Models, Chemical Toluene/*chemistry Flame ionization detector Gas chromatography Large-volume injector Volatile organic compounds;" |
| Notes: | "MedlineVikrant, Kumar Kim, Ki-Hyun Szulejko, Jan E eng Research Support, Non-U.S. Gov't Netherlands 2019/09/21 Environ Res. 2019 Nov; 178:108737. doi: 10.1016/j.envres.2019.108737. Epub 2019 Sep 10" |
