Study on β-Cyclodextrin-Functionalized Molten Salt Nitrogen-Doped Biochar and Its Adsorption Performance and...

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Tetracycline (TC) and methylene blue (MB) are common aquatic pollutants.
• Conventional adsorbents often have limitations in efficiency and capacity.
• Biochar-based materials offer a sustainable alternative for pollutant removal.

Purpose of the Study:

• To develop and evaluate N-doped biochar loaded with β-cyclodextrin (β-CD) for TC and MB removal.
• To investigate the adsorption performance and mechanism of the novel composite.
• To compare the efficacy of the developed adsorbent with existing materials.

Main Methods:

• Cotton stalks were used as a carbon source to prepare N-doped biochar.
• Molten salt activation, nitrogen doping, and β-CD grafting were integrated.
• Adsorption experiments were conducted to determine removal efficiency for TC and MB under various conditions.
• Adsorption kinetics and isotherms were analyzed using pseudo-second-order and Langmuir models.

Main Results:

• The composite, β-CD-NKBC-1.5, achieved a high specific surface area (1943 m²/g) and abundant active sites.
• Peak adsorption capacities reached 1269.8 mg/g for TC and 969.4 mg/g for MB at 308.15 K.
• Adsorption followed pseudo-second-order kinetics and Langmuir isotherm, indicating chemisorption.
• The adsorbent demonstrated high efficiency and selectivity in the presence of coexisting ions.

Conclusions:

• N-doped biochar loaded with β-CD is a highly effective adsorbent for TC and MB removal from aqueous solutions.
• The composite exhibits superior adsorption performance compared to many previously reported biochar adsorbents.
• The adsorption mechanism involves a combination of Lewis acid-base interactions, hydrogen bonding, π-π stacking, and pore filling.