Mesoporous Activated Biochar from Crab Shell with Enhanced Adsorption Performance for Tetracycline
Jiaxing Sun, Lili Ji, Xiao Han, Zhaodi Wu, Lu Cai, Jian Guo, Yaning Wang
Abstract
In this study, three mesoporous-activated crab shell biochars were prepared by carbonation and chemical activation with KOH (K−CSB), H3PO4 (P−CSB), and KMnO4 (M−CSB) to evaluate their tetracycline (TC) adsorption capacities. Characterization by SEM and a porosity analysis revealed that the K−CSB, P−CSB, and M−CSB possessed a puffy, mesoporous structure, with K−CSB exhibiting a larger specific surface area (1738 m2/g). FT-IR analysis revealed that abundant, surface ox-containing functional groups possessed by K−CSB, P−CSB, and M−CSB, such as −OH, C−O, and C=O, enhanced adsorption for TC, thereby enhancing their adsorption efficiency for TC. The maximum TC adsorption capacities of the K−CSB, P−CSB, and M−CSB were 380.92, 331.53, and 281.38 mg/g, respectively. The adsorption isotherms and kinetics data of the three TC adsorbents fit the Langmuir and pseudo-second-order model. The adsorption mechanism involved aperture filling, hydrogen bonding, electrostatic action, π-π EDA action, and complexation. As a low-cost and highly effective adsorbent for antibiotic wastewater treatment, activated crab shell biochar has enormous application potential.