کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
608355 | 880580 | 2012 | 7 صفحه PDF | دانلود رایگان |
Enrofloxacin (ENR) occurs widely in natural waters because of its extensive use as a veterinary chemotherapeutic agent. To improve our understanding of the interaction of this emerging contaminant with soils and sediments, sorption of ENR on homoionic smectites and kaolinite was studied as a function of pH, ionic strength, exchangeable cations, and humic acid concentration. Batch experiments and in situ ATR–FTIR analysis suggested multiple sorption mechanisms. Cation exchange was a major contributor to the sorption of cationic ENR species on smectite. The decreased ENR sorption with increasing ionic strength indicated the formation of outer-sphere complexes. Exchangeable cations significantly influenced the sorption capacity, and the observed order was Cs < Ca < K. The peak shifts of the COO− stretch, coupled CO stretch and OH deformation, and the result of irreversible desorption FTIR spectra indicated that OH of the carboxyl group was involved in the formation of inner-sphere surface complexes. The XRD analysis confirmed that interlayer intercalation is an important contributor to ENR sorption, while humic acid had a negligible contribution to the interlayer intercalation. The results of this study provide new insight into the molecular mechanisms of ENR sorption on clay minerals.
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► Multiple sorption mechanisms are responsible for the high ENR sorption capacity.
► pH, ionic strength, and clay conformation affect surface and interlayer sorption.
► Cation selectivity and hydrophobic sites on clay surface control ENR sorption.
Journal: Journal of Colloid and Interface Science - Volume 372, Issue 1, 15 April 2012, Pages 141–147