Conversion of polluted sediments into sustainable phosphate-adsorbing ceramics

Abstract

The management of sediment–water interfaces, particularly riverbed stability, is crucial for controlling pollutant buildup in sediments. Traditional restoration materials often face limitations such as unstable efficiency and high costs. This study developed ceramic particles from solid waste and examined the relationship between their coverage and phosphorus (P) release from sediment. Using Minitab to simulate the optimal raw material ratio (61.4 % dredged sediment, 14.4 % sewage sludge, and 24.2 % fly ash), we obtained ceramic particles with high P adsorption capacity (0.750 mg/g) and porosity (36.8 %). Characterization indicated that P adsorption was driven by chemical precipitation, ion exchange, and electrostatic attraction. In an in-situ remediation experiment, the particles significantly increased dissolved oxygen (0.462 → 5.26 mg/L), improved riverbed stability, and reduced erosion depth under wind disturbance by 63.8–64.1 %. Under weak to moderate winds, sediment resuspension decreased by 24.4 and 22.2 g/m², and sediment P release flux was substantially lowered. Even under strong winds, the P release flux in the backfill group decreased by 87.2 % compared with the control. The process also followed the principle of “treating waste with waste,” as P resources were recovered using a simple NaOH leaching agent, enabling regeneration and reuse of the ceramic particles—remarkably, regenerated particles maintained adsorption performance with only minimal decline. In conclusion, solid waste ceramic particles represent a cost-effective and sustainable strategy for managing polluted sediments, while also facilitating P recovery and reuse. This work provides a theoretical basis for sediment pollution control and supports ecological governance and restoration of rivers and lakes.