Desorption kinetics of arsenate from kao

Arsenic is highly toxic and poses a threat to both the environment and human health. The mobility and bioavailability of arsenic in soil are primarily governed by adsorption and desorption reactions. Although traditional batch desorption studies have provided insights into arsenic's environmental fate, they often fail to replicate the equilibrium conditions of natural environments. This study investigates the desorption of As(V), the predominant arsenic species in aerated soils, from kaolinite across varying pH levels using both batch and flow-through desorption experiments. Results indicate that traditional approaches underestimate the desorption rate of As(V) from kaolinite, revealing significant impacts of pH on the amount of As(V) desorbed. Both increases and decreases in pH from an initial value of 6.4 were found to enhance As(V) desorption. The modeling of desorption over time demonstrates that pH is a critical factor influencing As(V) interaction with kaolinite, leading to the formation of inner-sphere complexes on the surface. This research enhances the understanding of arsenic's fate in soils and underscores the importance of using dynamic desorption methodologies.