Shi Guowei, Li Yasong, Liu Yaci, Wu Lin
Fujian Provincial Key Laboratory of Water Cycling and Eco-Geological Processes Xiamen 361021 China
China Geological Survey, Hebei Province Key Laboratory of Groundwater Contamination and Remediation, Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences Shijiazhuang 050061 China.
RSC Adv. 2023 Mar 29;13(15):9892-9902. doi: 10.1039/d3ra00122a. eCollection 2023 Mar 27.
Sorption mechanisms of ionizable organic pollutants by biochars and approaches for the prediction of sorption are still unclear. In this study, batch experiments were conducted to explore the sorption mechanisms of woodchip-derived biochars prepared at 200-700 °C (referred as WC200-WC700) for cationic, zwitterionic and anionic species of ciprofloxacin (referred as CIP, CIP and CIP, respectively). The results revealed that the sorption affinity of WC200 for different CIP species was in the order of CIP > CIP > CIP, while that of WC300-WC700 remained the order of CIP > CIP > CIP. WC200 exhibited a strong sorption ability, which could be attributed to hydrogen bonding and electrostatic attraction with CIP, electrostatic attraction with CIP, and charge-assisted hydrogen bonding with CIP. Pore filling and π-π interactions contributed to the sorption of WC300-WC700 for CIP, CIP and CIP. Rising temperature facilitated CIP sorption to WC400 as verified by site energy distribution analysis. Proposed models including the proportion of the three CIP species and sorbent aromaticity index (H/C) can quantitatively predict CIP sorption to biochars with varying carbonization degrees. These findings are vital to elucidating the sorption behaviors of ionizable antibiotics to biochars and exploring potential sorbents for environmental remediation.
生物炭对可电离有机污染物的吸附机制以及吸附预测方法仍不清楚。在本研究中，进行了批量实验，以探究在200 - 700°C制备的木屑衍生生物炭（称为WC200 - WC700）对环丙沙星的阳离子、两性离子和阴离子物种（分别称为CIP⁺、CIP⁰和CIP⁻）的吸附机制。结果表明，WC200对不同CIP物种的吸附亲和力顺序为CIP⁺ > CIP⁰ > CIP⁻，而WC300 - WC700的吸附亲和力顺序仍为CIP⁺ > CIP⁰ > CIP⁻。WC200表现出较强的吸附能力，这可归因于与CIP⁺的氢键和静电吸引、与CIP⁰的静电吸引以及与CIP⁻的电荷辅助氢键。孔隙填充和π - π相互作用有助于WC300 - WC700对CIP⁺、CIP⁰和CIP⁻的吸附。通过位点能量分布分析证实，温度升高促进了CIP⁺对WC400的吸附。所提出的模型，包括三种CIP物种的比例和吸附剂芳香性指数（H/C），可以定量预测不同碳化程度的生物炭对CIP的吸附。这些发现对于阐明可电离抗生素对生物炭的吸附行为以及探索用于环境修复的潜在吸附剂至关重要。
