Sorption of Ciprofloxacin and Oxytetracycline Zwitterions to Soils and Soil Minerals: Influence of Compound Structure
Sorption of Ciprofloxacin and Oxytetracycline Zwitterions to Soils and Soil Minerals: Influence of Compound Structure
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DOI：
10.1021/es801277y
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发表时间：
2008-10-15
影响因子：
11.4
通讯作者：
Vasudevan, Dharni
中科院分区：
文献类型：
--
作者：
Carrasquillo, Anthony J.;Bruland, Gregory L.;Vasudevan, Dharni
与环丙沙星（CIP）两性离子相比，土霉素（OTC）两性离子在针铁矿和土壤上的吸附程度更大，有效阳离子交换容量（ECEC < 10 cmol（c）/kg），因为土霉素分子上相邻的羟基对（CIP中不存在）促进了土壤金属氧化物和铝硅酸盐边缘位点的更大表面络合。CIP在铝硅酸盐和具有“高”ECEC值（>10 cmol（c）/kg）的土壤上的吸附程度高于OTC。吸附的杂环化合物结构相似CIP表明，阳离子胺上的正电荷本地化和电荷离域的杂环的程度影响分子取向内的蒙脱石层间，货车德瓦尔斯相互作用，和吸附的潜力。结构上类似于OTC的化合物的吸附表明，更大的正电荷本地化的阳离子胺促进吸附到蒙脱石，而邻位取代的阴离子和阳离子基团的两性离子分子导致不利的库仑之间的相互作用的阴离子部分和带负电荷的表面和阻碍吸附。因此，更大的CIP两性离子吸附铝硅酸盐和“高”ECEC土壤导致阴离子和阳离子基团之间的距离更大，这最大限度地提高了库仑吸引力的表面。
Oxytetracycline (OTC) zwitterions sorbed to a greater extent than ciprofloxacin (CIP) zwitterions onto goethite and soils with moderate-to-low effective cation exchange capacities (ECEC < 10 cmol(c)/kg) because adjacent pairs of hydroxyl groups on the OTC molecule (absent in CIP) facilitated greater surface complexation to soil metal oxides and aluminosilicate edge sites. CIP sorbed to a higher extent than OTC onto aluminosilicates and onto soils with "high" ECEC values (>10 cmol(c)/kg). The sorption of heterocyclic compounds structurally similar to CIP indicated that both positive charge localization on the cationic amine and the extent of charge delocalization to the heterocyclic ring influenced molecular orientation within the montmorillonite interlayers, van der Waals interactions, and the potential for sorption. The sorption of compounds structurally similar to OTC revealed that greater positive charge localization on the cationic amine facilitated sorption to montmorillonite, whereas ortho substituted anionic and cationic groups on a zwitterionic molecule resulted in unfavorable Coulombic interactions between the anionic moiety and the negatively charged surface and hindered sorption. Thus, greater CIP zwitterion sorption to aluminosilicates and "high" ECEC soils resulted from greater distance between the anionic and cationic groups, which maximized Coulombic attraction to the surface.