固定化菌糠吸附剂对镉污染废水的深度净化

发布时间：2018-05-28 06:34

  本文选题：固定化菌糠 + 生物吸附　； 参考：《东北农业大学》2015年硕士论文

【摘要】：食用菌菌糠是食用菌工业生产的固体废弃物,直接排放到环境中容易对生态环境造成污染。菌糠上的官能有效基团非常之多,可以被用来作为吸附剂来清除废水体中的有害金属离子。传统的废水处理法有很多缺点,而用菌糠来吸附重金属的价格低廉、消耗小、对环境不存污染。但直接将菌糠投入水体中进行吸附,不利于吸附剂的再回收利用,可能导致其在水体中腐化,造成二次污染。本文通过海藻酸钠-聚乙烯醇对菌糠的固定化实验,制备出成分一致的颗粒。SA-PVA固定的菌糠吸附材料有以下优点:1、球状吸附材料易于回收,便于装入填充柱、塔中,有利于与生产实际接轨;2、SA-PVA固定化菌糠在吸附中不易破碎,且其多孔性更加有利于与重金属离子更好充分的结合;3、菌糠中木质素、纤维素、菌丝体等物质提供了大量与重金属离子结合的官能团;4、原料易于获得,且成本低廉。使用SA-PVA固定化菌糠对铅、铜、锌、镉这四种金属进行吸附效果的考察。结果显示出当pH为5~6之间,吸附温度超过25℃,溶液初始浓度在100-200mg/L之间时,固定化的菌糠对这几种金属可以超过60mg/g吸附量值。本实验着重对固定化菌糠对镉离子的吸附进行探讨,确定了单因素吸附条件:p H5,吸附温度25℃和初始浓度为100mg/L的情况下吸附镉离子时效果最好,吸附量甚至达70mg/g以上。对镉离子的吸附优先符合Langmuir吸附等温曲线,且R2值为0.998,从中可以初步判定固定化菌糠对镉的吸附为化学的单层吸附过程。然后利用SEM、FTIR、XRD、BET等仪器对其吸附的原理进行探讨解释,显示固定化菌糠的比表面积为51.1546m2/g,固定化菌糠对镉离子的吸附主要由物理和化学吸附两部分组成,包括配位、静电吸附和络合等反应,且吸附过程中羧基羟基、氨基等基团起到主要作用。在吸附-解吸附循环过程中,HCl被用来作洗脱剂,虽然Cd的洗脱率有所下降趋势,但到第五次循环时洗脱率仅比首次下降了15%。将固定好的菌糠装入循环柱中,在最适条件下对Cd2+废水的吸附进行模拟生产操作,测得其吸附容量与实验结果基本一致。实验结果表明,固定化菌糠因其较强的吸附能力、易于回收的特性以及低廉的价格,具有较大的开发潜力和较高的应用价值。
[Abstract]:Mushroom bran is a solid waste produced by edible fungus industry. It is easy to pollute the ecological environment when it is discharged directly into the environment. The functional effective groups on the bacterial bran are very numerous and can be used as adsorbents to remove harmful metal ions from the waste water. The traditional wastewater treatment method has many disadvantages, but the use of bacterial bran to adsorb heavy metals is low in price, low in consumption, and no pollution to the environment. However, it is unfavorable to reuse the adsorbent by directly putting the bacterial bran into the water body for adsorption, which may lead to the corruption and secondary pollution of the adsorbent. In this paper, through the immobilization experiment of sodium alginate and polyvinyl alcohol on the bacterial bran, the adsorption material fixed with the same composition of particle. SA-PVA has the following advantages: 1. The spherical adsorption material is easy to be recovered and easily packed into the packed column and column. The immobilized microbial bran is not easy to be broken in the adsorption process, and its porous property is more favorable to better and more fully binding with heavy metal ions, lignin and cellulose in the bacterial bran. Mycelium and other substances provide a large number of heavy metal ions bound to the functional group 4, the raw materials are easy to obtain, and the cost is low. The adsorption effects of lead, copper, zinc and cadmium on lead, copper, zinc and cadmium were investigated by SA-PVA immobilized bacterial bran. The results show that when pH is between 5 ~ 6, adsorption temperature is more than 25 鈩，

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