| 不同性质天然有机物对水中颗粒稳定性影响的机理研究 |
| 摘要点击 1611 全文点击 1132 投稿时间：2005-01-13 修订日期：2005-03-18 |
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| 中文关键词 天然有机物 颗粒稳定性 Zeta电位 等电点pHiep 分子量分布 官能团滴定 |
| 英文关键词 NOM particle stability Zeta potential pHiep MWD potentiometric titration |
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| 中文摘要 |
| 以不同来源天然有机物(NOM)及其各分离组份和模型颗粒Al(OH)3为研究对象,考察了pH值、二价金属离子Ca2+以及NOM的特性等因素对Al(OH)3颗粒稳定性的影响,并通过研究几种NOM吸附性能和吸附前后的特性变化,进一步探讨了NOM对颗粒稳定性的影响机理.结果表明,Al(OH)3颗粒的等电点pHiep出现在pH5～6之间,吸附态有机物是造成颗粒稳定性提高的主要原因,溶液中自由态Ca2+离子能够起到压缩双电层的作用,降低吸附态NOM之间的静电斥力,减小表面负电性,增加pHiep;吸附络合态Ca2+离子对颗粒表面负电性影响较小,但能够强化NOM在颗粒表面的吸附.NOM作为聚合态阴离子,在颗粒表面的吸附行为不符合Langmuir吸附模型,最大吸附发生在pH 4左右,吸附作用能够去除几种NOM中分子量较大的部分,并减小其羧基官能团的相对含量,NOM中大分子量、芳香性高的成分是造成水中颗粒稳定性提高的主要原因. |
| 英文摘要 |
| The effect of different NOM on colloidal stability in water was conducted by electrophoresis experiments with a model particle Al(OH)3 and the characteristic transformation of the isolated NOM after adsorption on the particle was discussed.The pH value,Ca2+ and characteristics of isolated NOM were evaluated as the main factors.The results indicated that the pHiep of Al(OH)3 was 5～6,and the adsorbed organic matter is the principal factor that decrease Zeta potential.It is the free Ca2+ in solution that reduces the electrostatic repulsion between adsorbed NOM molecules and make the particle surface less negatively charged;The "Cation Bridge" effect of complexed Ca2+ promoted the adsorption of isolated NOM although contributed little to particle stability.As polyanions,the adsorption of isolated NOM onto metal hydroxide did not follow the Langmuir adsorption model.The fraction with higher molecular weight and carboxylic acidity in different NOM was mainly removed by adsorption and the larger molecular weight and aromaticity fraction in NOM contributed to the increase of particle stability. |
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