Effect of temperature and aging on the adsorption and desorption of menadione in soil

Abstract

In this study, the effect of soil temperature and aging on the adsorption and desorption of menadione was investigated using the batch equilibrium method. The obtained isotherm data can be well fitted to the linearized form of the Freundlich equation, with R2 values ranging between 0.91 and 1.00. The adsorption and desorption of menadione in non‐aged (control) soil increased significantly when the temperature ranged between 15 and 37°C. Among soils that were amended with menadione and aged for 72 h, the sample with 2 μg·g−1 amendment showed significantly higher adsorption/desorption than those with 10 and 20 μg·g−1 amendments (P < 0.05). Thermodynamic and isotherm hysteresis analyses demonstrated that the sorption of menadione on the control and aged soils was a spontaneous and endothermic process. Physical sorption was the predominant mechanism, and there was negative hysteresis during desorption. Furthermore, thermodynamic calculation and infrared spectral analyses suggested that the main sorption force was hydrogen bonding in all the soil samples, and the entropy gain in the whole adsorbate‐adsorbent system was the main thermodynamic driving force. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 997–1004, 2017