A Stable Fe-Zn Modified Sludge-Derived Biochar for Diuron Removal: Kinetics, Isotherms, Mechanism, and Practical...

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Herbicides like diuron pose risks to water quality.
• Effective removal of diuron is crucial for environmental protection.
• Developing sustainable and efficient adsorbents is a key challenge.

Purpose of the Study:

• To develop and characterize a novel sludge-derived modified biochar (SDMBC600) for diuron removal.
• To investigate the adsorption mechanisms and kinetics of diuron onto SDMBC600.
• To evaluate the practical applicability and stability of SDMBC600 in water treatment.

Main Methods:

• Preparation of SDMBC600 using sludge-derived biochar (SDBC600) activated with Fe-Zn.
• Systematic study of SDMBC600's physico-chemical properties and diuron adsorption behavior.
• Analysis of adsorption kinetics, isotherms, mechanisms, and regeneration efficiency.

Main Results:

• SDMBC600 exhibited a large specific surface area (204 m²/g) and pore volume (0.0985 cm³/g).
• Adsorption followed pseudo-second-order kinetics and the Langmuir model, with a maximum capacity of 17.7 mg/g.
• Effective adsorption was maintained under various water quality conditions (pH 2-10, presence of humic acid and metallic ions).
• Adsorption mechanisms included surface complexation, π-π binding, hydrogen bonding, and pore filling.
• SDMBC600 demonstrated high stability with low metal leaching and retained 99.6% capacity after four regeneration cycles.

Conclusions:

• SDMBC600 is a highly effective adsorbent for diuron removal from water.
• The material's stability and regenerability support its practical application in water treatment.
• This biochar offers a promising solution for mitigating herbicide contamination in aquatic environments.