Abstract: The micro-interfacial interactions between sediment particles and heavy metal pollutants in aquatic environment are significant, with the surface morphological characteristics of sediment particles greatly influencing pollutant adsorption. Through both singular adsorption and competitive adsorption experiments, alongside BET (Brunauer-Emmett-Teller) analysis, we investigated the changes in structural characteristics such as pore volume and specific surface area of sediment particles after adsorbing Pb, Cu, and Cd. Furthermore, utilizing pore volume statistical methods, we quantitatively differentiated between the competitive and individual adsorption sites of Pb, Cu, and Cd on sediment particles. The findings indicate that mesopores ranging from 2 to 5 nm predominantly facilitate adsorption. Pb occupies more competitive adsorption sites on sediment particles than Cu and Cd, accounting for 43.69%, with Cu and Cd occupying 30.77% and 25.54%, respectively. Thus, Pb has the largest capacity of occupying competitive adsorption sites on sediment particles, followed by Cu and Cd in descending order. These results unveil the relationship between adsorption capacity and micro-adsorption sites at the nanoscale, providing new insights into the characteristics of competitive adsorption sites.

Key words: sediment particle, Pb-Cu-Cd system, BET experiment, pore characteristics, competitive sites