为研究茶多糖对氟的吸附特性,分析了不同温度、不同加氟量条件下,多糖吸附氟的能力,并对多糖吸附氟的等温吸附模型进行了拟合,分析了多糖结构和组成可能对吸附氟的影响。结果表明:温度对多糖结合氟的影响较大,40℃下多糖表面空松,吸附氟的能力最强,随着温度的升高,多糖表面逐渐变得致密,结合氟的能力下降,温度高于70℃后,多糖吸附氟量又会有所增加;40℃下,随着氟添加量的增加,多糖吸附氟量增加,当添加量达到多糖量1.8倍后,多糖吸附氟量不再增加。多糖吸附氟符合Langmuir等温吸附模型,分配因子RL均大于0小于1,属于有利的吸附。粗多糖脱蛋白脱色后,结构和组成发生较大变化,表面变得光滑平整,F-、Al3+、Mn2+和Fe3+的含量都急剧下降,吸附氟的能力也下降。说明多糖吸附氟的能力与多糖的组成、结构有关,蛋白质及Mn2+、Fe3+、Al3+在多糖结合氟中起到较重要作用。
The adsorption characteristics of tea polysaccharides (TPS) to fluorine under different temperatures and dose of fluoride was studied. The adsorption models were established and the structure and composition of TPS were analyzed. The results showed that the temperature was an important factor influencing fluorine adsorption of TPS.Loose surface structure was observed in TPS under 40℃ by SEM, which showed the strongest adsorption ability to fluorine. With the increase of temperature, the surface structure of TPS gradually became dense, while the adsorption ability to fluorine descended. However, the adsorption ability to fluorine incr eased after 70℃. The amount of fluorine absorption by TPS increased with the increasing of exposure amount of fluoride with its peak at 1.8 times of polysaccharide under 40℃. The adsorption behavior was in accordance with Langmuir model with the distribution factors (RL) between 0 and 1 and belonged to a favorable adsorption. As proteins and pigments were removed,,structure and composition of crude polysaccharides changed greatly, with sharp decrease of F-, Al3+, Fe3+ and Mn2+ contents and fluorine adsorption capacity. The results suggest that the characteristics of fluorine absorption is related to the composition and structure of polysaccharides. Proteins, Mn2+, Al3+ and Fe3+ might also play important roles in it.