State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
Bioresour Technol. 2013 May;136:87-93. doi: 10.1016/j.biortech.2013.02.098. Epub 2013 Mar 4.
Biochars produced from biomass residues have been recognized as effective sorbents to hydrophobic compounds, but knowledge on sorption of antibiotics to biochar and its mechanisms are still inadequate. Sorption of oxytetracycline (OTC) in aqueous solution to maize-straw-derived biochar, and the effect of pH and metal ions, was investigated in batch experiments, and the main sorption mechanisms were elucidated using FTIR and zeta potential measurements. The results showed that sorption of OTC on biochar was highly pH-dependant. The amount of sorbed OTC first increased and then decreased with increasing pH, and maximum sorption was achieved at pH 5.5. Cu(2+) enhanced the sorption of OTC, while Pb(2+) slightly reduced the sorption under acidic conditions. Other metal ions had no significant effect on the sorption of OTC to biochar. Surface complexation, through π-π interaction and metal bridging, was the most important sorption mechanism although cation exchange might have played a role.
生物炭由生物质残渣制成，已被认为是疏水性化合物的有效吸附剂，但关于抗生素在生物炭上的吸附及其机制的知识仍然不足。本研究通过批量实验考察了水溶液中氧四环素（OTC）在玉米秸秆衍生生物炭上的吸附及其对 pH 值和金属离子的影响，并通过傅里叶变换红外光谱（FTIR）和zeta 电位测量阐明了主要的吸附机制。结果表明，OTC 在生物炭上的吸附高度依赖于 pH 值。吸附的 OTC 量随 pH 值的增加先增加后减少，在 pH 5.5 时达到最大吸附量。Cu(2+) 增强了 OTC 的吸附，而 Pb(2+) 在酸性条件下略微降低了 OTC 的吸附。其他金属离子对 OTC 在生物炭上的吸附没有显著影响。表面络合，包括π-π 相互作用和金属桥联，是最重要的吸附机制，尽管阳离子交换可能也起了一定作用。
