Porosity optimization and Fe₂O₃ functionalization synergistically enhance nitrate adsorption on bamboo biochar

Area of Science:

• Environmental Chemistry
• Materials Science
• Water Treatment Technologies

Background:

• Nitrate-nitrogen (NO3--N) pollution poses a significant threat to aquatic ecosystems and human health.
• Conventional remediation methods often face limitations in efficiency and scalability.

Purpose of the Study:

• To develop an engineered iron-modified biochar (FeB) for enhanced NO3--N adsorption.
• To investigate the adsorption performance and removal mechanisms of FeB for aquatic nitrate contamination.

Main Methods:

• Sequential acid-washing and FeCl3-impregnation were used to synthesize FeB.
• Comprehensive characterization techniques (SEM, FTIR, XRD, XPS) were employed to analyze FeB properties.
• Adsorption experiments were conducted to evaluate capacity, kinetics, and influencing factors like pH and dosage.

Main Results:

• FeB exhibited optimized pore structure, enriched functional groups, and loaded Fe2O3 particles, resulting in a positive surface charge.
• The maximum adsorption capacity reached 6829.74 mg/kg, significantly exceeding that of pristine biochar.
• Nitrate removal followed pseudo-second-order kinetics and was attributed to electrostatic attraction, ligand exchange, and pore filling.

Conclusions:

• Engineered FeB is a highly efficient and stable adsorbent for NO3--N removal under neutral pH conditions.
• The developed FeB demonstrates significant potential for practical applications in wastewater treatment and constructed wetlands.
• This study offers a scalable and robust solution for mitigating aquatic nitrate pollution.