甲壳素-累托石复合微球的制备、表征及水中氟去除性能的研究.rar

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摘要:甲壳素,又名甲壳质(Chitin),是地球上除蛋白质外数量最大的含氮的天然有机化合物,同时也是自然中大量存在的唯一碱性多糖,和其衍生物壳聚糖被誉为继蛋白质、糖、脂肪、维生素、矿物质以外的第六生命要素[1]。本实验中,在综述了甲壳素和累托石性能的基础上,采用冻融技术制备甲壳、甲壳素/累托石、甲壳素/有机累托石微球,并通过实验研究了它们对水中氟离子的吸附特性,主要成果如下:

   (1)将甲壳素悬浮于8wt%NaOH/4wt%CO(NH2)2水溶液中,于-20℃下冻融得到甲壳素溶液;以此溶液为基础,将累托石和有机累托石按照实验方案制定的比例混合其中,通过针筒滴入乙酸溶液凝固成型,制备了甲壳素微球和甲壳素/累托石(有机累托石)微球。红外光谱和X衍射表征表明,与原始甲壳素微球相比,另外两种微球由于复合插层反应,结构和性质有了很大变化,吸附能力得到了改善。

   (2)研究了甲壳素、甲壳素/累托石、甲壳素/有机累托石微球吸附F-的特性,通过改变吸附剂剂量、溶液的初始氟浓度、甲壳素与累托石(有机累托石)的质量比、吸附时间、pH等条件,研究这些因素对吸附效果的影响。据观察,发现甲壳素/有机累托石在质量比1:0.4,剂量5g/L,初始氟浓度10mg/L,pH为6~7的情况下,除氟效果最佳,最大吸附量为1.80g/G,甲壳素/有机累托石微球在5h左右能够达到吸附平衡,快于另外两种微球,并且三种复合微球在吸附过程中受pH和阴离子存在的影响很明显,酸度过大时,大量H+与F-形成HF,降低F-浓度,碱度过大时,过多的OH-利用亲和优势与F-形成竞争吸附。阴离子存在的溶液pH偏碱性,因此大大降低了除氟效果。

关键词:甲壳素;累托石;有机累托石;除氟;吸附剂剂量;质量比;pH

 

Abstract:Chitin,is the highest concentrations of Nitrogen-containing natural organic compounds except protein. Chitin and its derivatives,known as the sixth element of life, protein,sugar,fat,vitaminns,minerals,other than.In this work,the applicability of chitin,chitin/rectorite and chitin/organic rectorite as adsorbents for the removel of excess fluoride of water was studied. 

Results:

(1)Chitin solubled in 8wt%NaOH/4wt%CO(NH2)2 aqueous solution,freeze-thaw at -20℃ to prepare chitin solution.This solution mixed with rectorite,to prepare chitin microspheres and a series of chitin-montmorillonite microspheres.IR spectra and X-ray diffraction characterization showed that in the composite microspheres,the chitin layer into the montmorillonite between then existence of strong interaction.

(2)The effects of various physico-chemical parametes such as pH,adsorbent dose,initial fluoride concentration and the presence of interfering ions on adsorption of fluoride were studied.It was observed that the uptake of fluoride was maximum at original pH (pH 6~7),acid and alkali environment will significantly reduce the adsorption,and the dosage of 5g/L is best.The rate of adsorption was rapid and maximum fluoride uptake was attained within 8h.By observation,when the mass ratio of chitin and organic rectorite is 1:0.4,the adsorption of the material is the highest.

Key words:chitin,rectorite,fluoride removal,dose,materials ratio of quality, pH,adsorption rate