Study on β-Cyclodextrin-Functionalized Molten Salt Nitrogen-Doped Biochar and Its Adsorption Performance and
Sining Li1, Yong Huang1,2, Qiushuang Cui1,3
1State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, China.
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In this study, we prepare N-doped biochar loaded with β-CD, using cotton stalks as a carbon source, and evaluate its removal efficiency for tetracycline (TC) and methylene blue (MB) from aqueous solutions. This composite uniquely integrates molten salt activation, nitrogen doping, and β-CD grafting, resulting in an exceptionally high specific surface area of 1943 m2/g and abundant active sites. The findings reveal that β-CD-NKBC-1.5 (5 g of N-doped biochar loaded with 1.5 g of β-CD) demonstrates remarkable capabilities for both TC and MB removal across an extensive pH spectrum, reaching peak adsorption levels of 1269.8 and 969.4 mg/g at 308.15 K, respectively-outperforming most previously reported biochar-based adsorbents. The adsorption process is well described by the pseudo-second-order and Langmuir models, indicating that monolayer chemisorption is the dominant mechanism. β-CD-NKBC-1.5 exhibits preferential adsorption for TC and MB and maintains high adsorption efficiency even with coexisting ions (Na+, K+, Ca2+, Mg2+, and SO42-) at concentrations up to 500 mg/L. The adsorption mechanism involves Lewis acid-base interactions, hydrogen bonding, π-π stacking, and pore filling.
