Competitive and synergistic adsorption of binary volatile organic compound mixtures on activated carbon**Project supported by the National Natural Science Foundation of China (Grant No. 11574401), the Science Foundation of China University of Petroleum, Beijing (Grant Nos. 2462017YJRC029 and yjs2017019), and the Beijing Natural Science Foundation, China (Grant No. 1184016).

Abstract

The adsorption of four substances and their binary mixture is investigated via the terahertz time domain spectroscopy (THz-TDS). The selected unary compound (ethanol, acetone, ethyl acetate, and n-propyl acetate) and binary mixture (solution 1 is composed of ethanol and acetone, and solution 2 is composed of ethyl acetate and n-propyl acetate) exhibit different adsorption behaviors with varied polarities. In comparison with single component, solution 1 shows shorter adsorption equilibrium time, faster adsorption rate, and stronger adsorption capacity, which conform to a synergistic adsorption mechanism, while the competitive behavior is attributed to the slower adsorption in solution 2. In addition, the pseudo-second-order equation with terahertz parameter is used to assess the rate of binary component organics. The present results indicate a further understanding of multicomponent adsorption mechanisms.