山楂汁中有机酸和总黄酮吸附动力学研究

Study on the adsorption kinetics of organic acids and total flavonoids in hawthorn fruit juice

为了探讨山楂汁中有机酸和总黄酮的同时吸附的动力学规律,实验设计含有不同浓度有机酸和总黄酮的山楂果汁,与一定量的树脂(D941树脂或NKA树脂)混合,搅拌吸附,用Langmuir等温模型和Freundlich等温模型分析吸附平衡数据。结果表明,D941树脂和NKA树脂对山楂汁中的有机酸和总黄酮的吸附平衡数据符合Langmuir等温模型。根据Langmuir等温模型,求出这两种树脂分别对有机酸和总黄酮的最大吸附,与大孔吸附树脂NKA相比,发现大孔弱碱性阴离子交换树脂D941吸附较多的有机酸和较少的总黄酮,可以作为山楂果汁降低有机酸而保留总黄酮研究中较为理想的树脂。D941树脂和NKA树脂对山楂汁中的有机酸的吸附能力低于对纯柠檬酸溶液的吸附能力,证明总黄酮的吸附会阻碍有机酸的吸附。

To investigate the adsorption kinetics of organic acids and total flavonoids in hawthorn fruit juice at the same time,hawthorn fruit juice containing different concentrations of organic acids and total flavonoids was designed,then mixed with a certain dose of the resin（D941 resin or NKA resin） and the adsorption occurred by stirring.The equilibrium data was analyzed in terms of the Langmuir and Freundlich isotherm models.As the results showed,the adsorption equilibrium data of organic acids and total flavonoids on D941 resin and NKA resin was fitted to the Langmuir isotherm model.The maximum adsorption capacities of organic acids and total flavonoids on the two resins were calculated respectively in term of the Langmuir isotherm model.It was found that the macroporous weakly basic anion exchange resin（D941） adsorbed more organic acids and less total flavonoids than the macroporous resin（NKA）.Therefore,D941 resin could be used as a more ideal resin reducing the content of organic acids but retaining the content of total flavonoids.The adsorption capacity of organic acids on D941 resin or NKA resin was lower than citric acid solution,which proved the adsorption of total flavonoids hindered the adsorption of organic acids.