Wu Yi-xiao, Li Ai-min, Wang Di-hua, Zhang Wei-hao
Huan Jing Ke Xue. 2015 Jan;36(1):215-20.
The experiments were conducted to investigate the adsorption behavior of tetracycline on a kind of nano-sized amorphous carbon, which was synthetized in a molten salt electrochemical system, comprising a eutectic mixture of Li-Na-K carbonates. The results showed that, the carbon powder had a good adsorption performance. At 298K, the maximum adsorption capacity of tetracycline was 127.76 mg x g(-1). The adsorption data could be well fitted by the pseudo-second-order model and the Freundlich isotherm. Also, the thermodynamic tests for the adsorption were conducted. The adsorption was endothermic and spontaneous reaction with chemical bond as the dominant. The adsorption was pH dependent. The adsorption capacity reached the maximum when solution pH was 4 in the range from 2 to 11. The existence of cations had little effects on the adsorption. The adsorption capacity increased with the concentration of cations to a certain extent. Ion exchange may be one of the adsorption mechanisms, as well as, electric attraction and hydrogen bond. Moreover, desorption experiments were carried out in 0.25 mol x L(-1) CaCl2 or NaCl solution respectively. Desorption efficiency ranged from 7.42% to 25%, which was at a relatively low level. The result indicated that the chemical adsorption process was strong.
进行了实验以研究四环素在一种纳米级非晶态碳上的吸附行为，该碳是在包含Li-Na-K碳酸盐共晶混合物的熔盐电化学系统中合成的。结果表明，碳粉具有良好的吸附性能。在298K时，四环素的最大吸附容量为127.76 mg x g(-1)。吸附数据可以很好地用准二级模型和Freundlich等温线拟合。此外，还进行了吸附的热力学测试。吸附是吸热的自发反应，以化学键为主导。吸附依赖于pH值。在2至11的范围内，当溶液pH值为4时吸附容量达到最大。阳离子的存在对吸附影响很小。吸附容量随阳离子浓度的增加而在一定程度上增加。离子交换可能是吸附机制之一，还有电吸引和氢键。此外，分别在0.25 mol x L(-1) CaCl2或NaCl溶液中进行了解吸实验。解吸效率在7.42%至25%之间，处于相对较低的水平。结果表明化学吸附过程很强。
