环境工程_壳聚糖改性絮凝剂的制备及在染料废水处理中的应用.rar

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摘要:壳聚糖(CTS)是一种天然有机高分子化合物,无毒副作用,可以完全生物降解。其分子结构为直链型,分子上大量存在氨基与羟基活性基团,可发生羧基化、乙酰化、羟甲基化、氧化、酯化等反应,也可在双官能团的醛或酸酐等交联剂作用下发生交联反应,故在医药、环保、食品、造纸、农业等诸多领域得到了广泛的应用。在水处理领域,壳聚糖可作为絮凝剂或吸附剂。但是,壳聚糖作为絮凝剂单独使用时,存在受pH影响大、阳离子特性弱、稳定性差及难以适用于各种复杂水质等缺点,必须对其进行改性处理。

   文中以Fe3+为改性剂,制备了CTS-Fe絮凝剂,通过对制备过程中的溶液pH、CTS/Fe质量比、反应时间三个影响因素进行研究,找出最佳的制备条件。同时,通过对CTS、PFC、CTS-PFC、CTS-Fe的絮凝性能比较,发现CTS-Fe的絮凝效果优于其它三种絮凝剂,证明CTS与Fe并不是简单的复配,而是两者的反应物。将制备好的絮凝剂分别在直接兰、活性红、分散深兰三种染料废水中应用,对废水pH、絮凝剂投加量、废水浓度及沉降时间进行探讨,得出最佳的絮凝工艺条件。

   针对絮凝过程中,絮体颗粒不够大及沉速问题,对絮凝剂再次进行改进,制备CTS-Fe-Al絮凝剂,与CTS-Fe絮凝效果对比,得出CTS-Fe-Al絮凝剂效果较好。

关键词:壳聚糖  络合  改性絮凝剂  染料废水

 

Abstract:Chitosan is a kind of inartificial organic compound of macromolecule in nature, which has the advantage of no toxic side effects and complete biological decomposition.Chitosan, whose structure is straight chain, has lots of amino and hydroxy reactive groups in the molecule.As carboxyl, acetylation, hydroxy-methylation, oxidation, esterification and cross-linking(when cross-bifunctional aldehyde or anhydride is used as linking agents) reactions occurs in the molecule, it has been widely applied in many fields such as medicine, environmental protection, food, paper, agriculture.In the field of water treatment, chitosan can be used as a flocculant or adsorbent.However, when chitosan is used as a flocculant separately, with the influence of pH, low cation characteristics, poor stability and difficult to apply in a variety of complex water quality and et al, chitosan must be taken to be modified.

    In this article, as Fe3+ for a modifier, the research prepared Chitosan complex iron flocculant(CTS-Fe).Three factors during the preparation process such as pH of flocculant solution, the CTS/Fe ratio and reaction time were studied to identify the optimum preparation conditions.At the same time, comparing the flocculation performance of CTS, PFC, CTS-PFC and CTS-Fe, we found that the CTS-Fe flocculation is better than the other three flocculants.So CTS and Fe do not simply mix, but the reaction of both matters.Flocculant Prepared was applied in the dyes wastewater of Direct Blue, Reactive Red, Scattered Dark Blue.The effects of pH of wastewater, flocculant dosage, dye concentration and settling time were investigated to explore the best flocculation conditions.

    During the flocculation period, the floc particles is not enough large and the problem of  settling velocity, so the flocculant was modified again to CTS-Fe-Al flocculant.Compared with the CTS-Fe flocculation, the performance of CTS-Fe-Al flocculant is better.

Key words:Chitosan  Complex  Modified flocculant  Dyeing wastewater