| 一种纳米级不定形碳对水中四环素的吸附研究 |
| 摘要点击 1774 全文点击 949 投稿时间：2014-04-30 修订日期：2014-08-02 |
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| 中文关键词 纳米材料 不定形碳 四环素 吸附 解吸 |
| 英文关键词 nano materials amorphous carbon tetracycline adsorption desorption |
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| 中文摘要 |
| 研究了一种新型纳米级不定形碳对水中四环素的吸附作用. 结果表明, 在Li-Na-K碳酸盐的共熔体系中生成的碳粉对四环素表现出了良好的吸附性能. 在298K下,碳粉对四环素的吸附行为更符合拟二级动力学模型和Freundlich吸附等温线,最大吸附容量达到127.76mg·g-1. 热力学计算结果表明,吸附过程是吸热的、自发的,以化学吸附为主. 吸附行为表现出明显的pH依赖性,当溶液的起始pH在2~11,pH为4时碳粉对四环素的吸附量最大. 溶液中的阳离子对吸附有一定的影响,但影响不大,随着阳离子浓度的增加,吸附量在一定程度上逐渐减小. 离子交换作用可能是吸附的原理之一,还可能同时存在静电引力、氢键等作用. 分别使用0.25mol·L-1的CaCl2和NaCl溶液进行解吸实验,解吸效率在7.42%~25%,解吸效率较低,说明吸附的化学作用较强. |
| 英文摘要 |
| 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·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·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. |
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