A novel Ca/Mn-modified biochar recycles P from solution: mechanisms and phosphate efficiency

Area of Science:

• Environmental Science
• Materials Science
• Agricultural Science

Background:

• Excessive phosphate application leads to phosphorus resource depletion and water eutrophication.
• Developing efficient phosphorus recovery methods is crucial for environmental sustainability and resource management.

Purpose of the Study:

• To synthesize a novel calcium-manganese-impregnated biochar (CMBC) composite for phosphate recovery.
• To evaluate the efficiency of P-sorbed CMBC as a phosphorus fertilizer in pot experiments.

Main Methods:

• Co-pyrolysis synthesis of Ca-Mn-impregnated biochar (CMBC) at 600 °C.
• Phosphate sorption kinetics and isotherm studies.
• Pot experiments assessing plant growth and phosphorus uptake using P-sorbed CMBC.

Main Results:

• CMBC composites, particularly CM1BC and CM2BC, demonstrated high phosphate sorption efficiency.
• P-sorbed CMBC significantly enhanced plant dry weight, fresh weight, and phosphorus content.
• Maximum P adsorption capacities reached up to 20.84 mg g⁻¹ for CM2BC, fitted by the Langmuir model.

Conclusions:

• P-sorbed CMBC effectively recovers phosphate from solutions and acts as a viable phosphorus fertilizer.
• The study highlights the potential of modified biochar for sustainable phosphorus management and agricultural applications.