Adsorption Property and Mechanism of Oxytetracycline onto Willow Residues
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, Chang’an University, Xi’an 710054, China
School of Environmental Science and Engineering, Chang’an University, Xi’an 710054, China
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China
Liaoning Zhongwang Group Co., Ltd., Liaoyang 111003, China
School of Geography and Tourism, Shaanxi Normal University, Xi’an 710054, China
Authors to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2018, 15(1), 8; https://doi.org/10.3390/ijerph15010008
Received: 7 November 2017 / Revised: 13 December 2017 / Accepted: 20 December 2017 / Published: 22 December 2017
(This article belongs to the Special Issue Proceedings of 2nd International Symposium on Environment Science and Health)
To elucidate the adsorption property and the mechanism of plant residues to reduce oxytetracycline (OTC), the adsorption of OTC onto raw willow roots (WR-R), stems (WS-R), leaves (WL-R), and adsorption onto desugared willow roots (WR-D), stems (WS-D), and leaves (WL-D) were investigated. The structural characterization was analyzed by scanning electron microscopy, Fourier-transform infrared spectra, and an elemental analyzer. OTC adsorption onto the different tissues of willow residues was compared and correlated with their structures. The adsorption kinetics of OTC onto willow residues was found to follow the pseudo-first-order model. The isothermal adsorption process of OTC onto the different tissues of willow residues followed the Langmuir and Freundlich model and the process was also a spontaneous endothermic reaction, which was mainly physical adsorption. After the willow residues were desugared, the polarity decreased and the aromaticity increased, which explained why the adsorption amounts of the desugared willow residues were higher than those of the unmodified residues. These observations suggest that the raw and modified willow residues have great potential as adsorbents to remove organic pollutants.