Using bio-based CaCO₃ functionalized sediment to simultaneously remove algae and COD through adsorption and...

Area of Science:

• Environmental Science
• Materials Science
• Biotechnology

Background:

• In-situ turbidity enhancement for algae control can increase chemical oxygen demand (COD) due to incomplete organic removal.
• Developing effective methods for simultaneous algae and COD control in reservoirs is crucial for water quality management.

Purpose of the Study:

• To engineer a biologically synthesized bio-CaCO3-modified sediment for simultaneous algae suppression and COD reduction.
• To investigate the material's properties, adsorption mechanisms, and performance in controlling key water quality parameters.

Main Methods:

• Bio-CaCO3 sediment synthesized using Bacillus-induced carbonate precipitation.
• Characterization of material properties using SEM, XRD, FTIR, and BET.
• Algal adsorption studies with Microcystis aeruginosa, Chlorella, and Limnothrix, analyzed using Langmuir and pseudo-second-order models.
• Evaluation of interaction forces using XDLVO theory and DFT analysis.
• Optimization of treatment conditions and assessment of pollutant removal efficiency and calcium leaching.

Main Results:

• The bio-CaCO3 material formed 15-30 nm core-shell clusters with enriched functional groups and mesopores.
• Adsorption followed Langmuir monolayer binding and pseudo-second-order kinetics, indicating strong EPS-Bio-CaCO3 interactions.
• Optimal conditions achieved 93.8% Chl-a removal, 88.6% COD reduction, and 87.5% turbidity control with minimal Ca2+ leaching.

Conclusions:

• The bio-CaCO3-modified sediment offers a stable and eco-friendly strategy for the simultaneous control of algae and COD in aquatic environments.
• The material's effectiveness is attributed to integrated chemisorption, interfacial adhesion, and pore confinement mechanisms.
• This approach provides a promising solution for in-situ sediment remediation and dual pollutant control in reservoirs.