Effect of Biofilm on the Phosphorus Adsorption Characteristic of Sediment Particles

Biofilm secreted due to the metabolic activities of microorganisms has a great impact on the geochemical and biological characteristics of sediment particles and their environmental effects in hydro-environmental systems, yet little effort has been made to study the considerable variability in the element adsorption process of sediment particles caused by the growth of biofilm. Understanding the variability of adsorption characteristic of sediment particles associated with biofilm growth and quantifying the scale of the adsorption isotherm parameters over which these changes occur are important for developing suitable experimental designs and for understanding how biofilms mediate sediment properties and environmental factors. In this paper, a phosphorous compound is taken as the adsorbate used to study the influence of biofilms on the phosphorus adsorption characteristic of sediment particles. Isothermal equilibrium adsorption experiments for sediment particles coated with biofilms from different growth times on phosphorus are performed, and the Langmuir adsorption isotherm is adopted to analyze the adsorption rule of biofilm sediment on phosphorus under the impact of biofilm. This study provides the first evidence for the interaction of sediment particles, biofilms and adsorbed elements in water environments. The current research demonstrates that exposed sediment in aquatic environments can be rapidly colonized by biofilm secreted by microorganisms. Moreover, biofilm growth significantly affects sediment properties, supporting field measurements that have shown significant differences in the adsorption characteristic of sediment coated with biofilm at different growth phases. The results show that the phosphorus adsorption capacity of sediment particles increases with the growth of biofilm. The expression describing the adsorption isotherm parameter of the maximum material (element) adsorption capacity of sediment changing over time is proposed based on the experimental data, which show directional responses in the biogeophysical variables resulting from biofilm growth and development.