Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Environ Sci (China). 2018 Nov;73:20-30. doi: 10.1016/j.jes.2017.12.024. Epub 2018 Jan 7.
In this study, used tea leaves (UTLs) were pyrolyzed to obtain used tea-leaf biochar (UTC), and then the UTC was used as an adsorbent to remove ciprofloxacin (CIP) from aqueous solutions. Batch experiments were conducted to investigate the CIP adsorption performance and mechanism. The results showed that the CIP-adsorbing ability first increased and then declined as the UTC pyrolysis temperature increased. The UTC obtained at 450°C presented excellent CIP-absorbing ability at pH6 and 40°C. The maximum monolayer adsorption capacity was 238.10mg/g based on the Langmuir isotherm model. The pseudo-second-order kinetic equation agreed well with the CIP adsorption process, which was controlled by both external boundary layer diffusion and intra-particle diffusion. The characterization analysis revealed that the OH groups, CC bonds of aromatic rings, CH groups in aromatic rings and phenolic CO bonds play vital roles in the CIP adsorption process, and that the NC, NO, OCO and COH groups of UTC were consumed in large quantities. π-π interactions, hydrogen bonding and electrostatic attraction are inferred as the main adsorption mechanisms. The present work provides not only a feasible and promising approach for UTLs utilization but also a potential adsorbent material for removing high concentrations of CIP from aqueous solutions.
在这项研究中，用过的茶叶（UTLs）被热解以获得用过的茶生物炭（UTC），然后将 UTC 用作吸附剂从水溶液中去除环丙沙星（CIP）。进行了批量实验以研究 CIP 的吸附性能和机制。结果表明，随着 UTC 热解温度的升高，CIP 的吸附能力先增加后降低。在 pH6 和 40°C 下，在 450°C 下获得的 UTC 具有出色的 CIP 吸附能力。根据 Langmuir 等温模型，最大单层吸附容量为 238.10mg/g。准二级动力学方程很好地符合 CIP 吸附过程，该过程受外部边界层扩散和颗粒内扩散的共同控制。特征分析表明，OH 基团、芳环的 CC 键、芳环中的 CH 基团和酚 CO 键在 CIP 吸附过程中起着重要作用，并且 UTC 的 NC、NO、OCO 和 COH 基团大量消耗。推断 π-π 相互作用、氢键和静电吸引是主要的吸附机制。本工作不仅为 UTLs 的利用提供了一种可行且有前途的方法，而且为去除水溶液中高浓度 CIP 提供了一种潜在的吸附剂材料。
