Adsorption kinetics of Escherichia coli in cinnamon soil of North China

As an indicator bacterium of environmental biological contamination, Escherichia coli (E. coli) was used as the research object, and the adsorption kinetics of Escherichia coli in typical agricultural soil of North China under different factors (biochar, ionic strength, indigenous microorganisms) were studied based on four adsorption kinetic models. The results showed that the process of adsorption kinetics of E. coli in soil can be refined to three following stages: fast adsorption (0～20 min), slow adsorption (20～60 min) and equilibrium adsorption (80～120 min). The quasi-secondary kinetic equation was suitable for describing the adsorption kinetics of E. coli. The adsorption of E. coli by soil was heterogeneous chemisorption, and the adsorption rate of E. coli was mainly fluctuated by the synergistic effect of surface adsorption and intragranular diffusion mechanism. The addition of biochar and the improvement of ionic strength increased the adsorption capacity of E. coli, while the presence of indigenous microorganisms decreased the adsorption capacity of E. coli in soil. These results can provide the theoretical basis of controlling pathway for pathogenic bacterial contamination in cinnamon soil of North China.