| 摘要: |
| 以苯酚为研究对象, 系统地研究了其在南海沉积物上的吸附行为。实验中作者利用紫外可见分光光度计测定苯酚在沉积物上吸附前后的浓度变化, 从而可以根据平衡浓度(Ce)和吸附在沉积物上的量(Cs)的关系来推测苯酚在沉积物上的吸附机理。研究表明, 苯酚在海洋沉积物上的吸附行为可以同时很好地用Freundlich型、Langmuir型和线型三种吸附等温式来描述, 这说明其吸附行为比较复杂。另外, 通过改变吸附条件发现苯酚吸附行为受沉积物有机质的含量、介质的盐度、温度、酸度等因素的影响, 并且饱和吸附量随着沉积物有机质含量、介质盐度和酸度的升高而增大,随着温度的升高而减小。
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| 关键词: 苯酚,海洋沉积物,吸附等温线,饱和吸附量 |
| DOI：10.11693/hyhz200304001001 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目,40176023号 |
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| SORPTION BEHAVIOR OF PHENOL IN MARINE SEDIMENTS |
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WU Ping, YANG Gui-Peng, ZHAO Run-De
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College of Chemistry and Chemical Engineering, Ocean University of China
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| Abstract: |
| Phenol is a toxic organic pollutant that is ubiquitous in the environment. A great amount of waste water containing phenol is let out to the marine environment, which has done great harm to the human being and marine organisms. Investigations of its sorption behavior on marine sediments are of great significance for understanding its transference in the environment and its effect on marine ecological system. Moreover, the studies of this aspect can also provide a theoretical foundation for environment protection.
In this paper, the sorption behavior of phenol in marine sediments was studied under different experimental conditions in terms of salinity, temperature and acidity, with an aim of better understanding its removal pattern in marine environment via solid-liquid interfacial interaction. The sediment samples were collected from the South China Sea and treated by three methods, using natural seawater collected from Jiaozhou Bay and two types of diluted seawater (DSW1 and DSW2), to study how salinity affected the sorption behaviors of phenol. Meanwhile, three different temperatures(20℃, 25℃, 30℃) and a wide pH range (2.50—10.00) were chosen to study the influence of temperature and acidity.
For the experiment of sorption equilibration time, 100 mg of the sediment, 10 ml of phenol standard solution and 90ml of natural seawater were added to a series of 250 ml ground glass-stoppered flasks to make up a whole suspension volume of 100 ml. The solution pH was adjusted to (8.00±0.03)℃ and then shaken at (25±0.5)℃ in a model SHA-C constant-temperature shaker at different time intervals. Solid and aqueous phases were separated by a model LG10-2.4A centrifuge and the supernatant solution was analyzed by a Model UV-1100 spectrophotometer. Sorption isotherm experiments were carried out by the similar method to the above. The main difference was that the volume of standard solution added was variable. Adsorption amount of phenol was calculated from the difference between the initial concentration and the equilibrium solution concentration. Blank sorption experiment proved that the amount of phenol adsorbed to the glass wall was negligible.
Freundlich, Langmuir and linear models were all fit for describing the sorption behavior of phenol in marine sediments. Sorption amount in NO.1 sediment < NO.2 sediment < NO.3 sediment, this order just coincided with the organic carbon content of sediments; there was a significant correlation between Kd and organic carbon content foc of the sediments. Further, there is a pattern of sorption amount on HCl-treated sediments > no treatments > H2O2 treatments, because these treatments relatively changed the organic carbon content of sediments. Moreover, because marine sediment components were extremely complex, the other two models were all fit for describing its sorption behavior, with the surface and micro porosity action also playing a main role in its sorption process. The sorption behaviors of phenol in marine sediments were affected by various factors including organic carbon content of sediments, aqueous media, temperature and acidity. The sorption amount of phenol increased with increasing organic carbon content, salinity and acidity, but decreased with increasing temperature. When the organic carbon content increased the partition effect increased, and when salinity increased and temperature decreased the solubility of phenol decreased, resulting in increase of sorption amount. In addition, the ionicity of phenol in solutions decreased with increasing acidity, which led to the increase of sorption amount. Marine sediments could strongly adsorb organic pollutants such as phenol and, therefore, the sorption of organic pollutants in marine sediments plays an important role on the purification of seawater.
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| Key words: Phenol, Marine sediment, Sorption isotherm, Sorption amoun |
