Tetracycline Adsorption Performance and Mechanism Using Calcium Hydroxide-Modified Biochars

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Tetracycline contamination in various environments poses ecological risks.
• Biochar, particularly alkali-modified biochar, shows promise for wastewater pollutant removal.

Purpose of the Study:

• To investigate the tetracycline adsorption performance and mechanism of alkali-modified biochars from nine waste sources.
• To identify the optimal alkali modifier and biomass source for effective tetracycline adsorption.

Main Methods:

• Pyrolysis of nine waste materials at 500 °C.
• Modification of biochars using four alkalis, with a focus on calcium hydroxide.
• Adsorption experiments to determine tetracycline removal efficiency and capacity.

Main Results:

• Calcium hydroxide modification at 500 °C yielded the most effective biochar.
• Straw biomass, particularly corn straw, was most suitable for calcium hydroxide modification.
• Calcium hydroxide-modified corn straw biochar achieved a maximum adsorption capacity of 93.46 mg g⁻¹, a significant increase from 8.22 mg g⁻¹ for pristine biochar.

Conclusions:

• Calcium hydroxide-modified corn straw biochar is a highly efficient, cost-effective, and environmentally friendly adsorbent for tetracycline.
• Adsorption mechanisms include hydrogen bonding, functional groups, metal complexation, and electrostatic attraction.