Martínez-Mejía Mónica J, Sato Isabela, Rath Susanne
Institute of Chemistry, University of Campinas - UNICAMP, PO Box 6154, Campinas, SP, 13084-971, Brazil.
Environ Sci Pollut Res Int. 2017 Jul;24(19):15995-16006. doi: 10.1007/s11356-017-9210-3. Epub 2017 May 23.
Veterinary antimicrobials are emerging environmental contaminants of concern. In this study, the sorption of enrofloxacin (ENR) onto humic acids (HAs) extracted from three Brazilian soils was evaluated. HAs were characterized by elemental analysis and solid C nuclear magnetic resonance spectroscopy. The sorption of ENR onto HAs was at least 20-fold higher than onto the soils from which they were separated. Ionic and cation bridging are the primary interactions involved. The interactions driven by cation exchange are predominant on HAs, which appear to have abundant carboxylic groups and a relatively high proportion of H-bond donor moieties with carbohydrate-like structures. Interactions explained by cation bridging and/or surface complexation on HAs are facilitated by moieties containing conjugated ligands, significant content of oxygen-containing functional groups, such as phenolic-OH or lignin-like structures. HAs containing electron-donating phenolic moieties and carboxylic acid ligand groups exhibit a sorption mechanism that is primarily driven by strong metal binding, favoring the formation of ternary complexes between functional groups of the organic matter and drugs.
兽用抗菌剂正成为令人担忧的环境污染物。在本研究中，评估了恩诺沙星（ENR）在从三种巴西土壤中提取的腐殖酸（HAs）上的吸附情况。通过元素分析和固体碳核磁共振光谱对腐殖酸进行了表征。恩诺沙星在腐殖酸上的吸附至少比其分离出的土壤高20倍。离子和阳离子桥联是主要的相互作用方式。阳离子交换驱动的相互作用在腐殖酸上占主导地位，腐殖酸似乎具有丰富的羧基以及相对较高比例的具有类碳水化合物结构的氢键供体部分。含有共轭配体、大量含氧官能团（如酚羟基或类木质素结构）的部分促进了腐殖酸上由阳离子桥联和/或表面络合所解释的相互作用。含有供电子酚类部分和羧酸配体基团的腐殖酸表现出一种主要由强金属结合驱动的吸附机制，有利于在有机物官能团和药物之间形成三元络合物。
