Impact of nanomaterials on microbial communities in the carbon sequestration processes of urban river ecosystems

Abstract

Herein, zero-valent iron nanoadsorbents were synthesized by hydrothermal and coprecipitation methods. The structure and morphology of the materials were characterized through X-ray diffraction, energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy with EDS. The adsorption performance of nanoscale Fe2O3 nanomaterials was evaluated. Additionally, adsorption experiments were conducted with varying amounts of nanomaterials and initial concentrations of dissolved organic carbon (DOC) in water. The results showed that as the initial concentration of the DOC in water increased, the efficiency of organic carbon removal gradually decreased. In particular, when the initial concentration of the DOC increased from 20 to 35 mg/L, the removal efficiency of the nanomaterials decreased from 85% to 55%. Furthermore, a considerable decrease in the removal efficiency was observed between 30 to 60 min. After 60 min, the efficiency of organic carbon removal was almost constant. The increase in the initial concentration of DOC in water resulted in a gradual decrease in the efficiency of its removal. The decrease in the organic carbon content in water lead to a scarcity of carbon sources for microbial reproduction, thereby reducing the microbial population considerably. This study provides a clear evidence of the pronounced carbon fixation effect of nanomaterials and their ability to control microbial population in aquatic ecosystems.