磁性桉叶废渣活性炭处理含铬电镀废水的机理与应用研究

发布时间：2018-04-13 22:01

  本文选题：磁性活性炭 + 桉叶残渣　； 参考：《广西大学》2015年硕士论文

【摘要】：吸附法去除水中污染物受到大量研究学者的关注。因传统吸附剂(如活性炭等)难以从处理后的废水中实现固液分离,其实际应用受到限制。将吸附剂赋磁并应用于水中污染物的去除是一个相对较新的领域,利用磁场来分离磁性吸附剂,具有省时、价廉、安全、高效等优点。本文将广西大量种植的尾叶桉树叶提取桉叶油后的废渣,通过化学共沉淀法制成磁性活性炭(Magnetic Eucalyptus Leaf Residue Biochar, MELRBC),应用于水中Cr离子的去除,考察影响吸附的各种因素以及磁分离效果,并将吸附—磁分离联用技术用于实际含铬电镀废水的处理,初步探讨其在含铬电镀废水处理方面的应用潜力。主要结论如下：(1)赋磁后,活性炭理化性质发生改变。共沉淀生成的铁氧化物(主要为Fe304)有选择地分布在活性炭表面,其平均粒径为22 nm；活性炭的C含量由原来的46.2%变为38.4%,比表面积和微孔容积均有所下降,但中孔容积有所上升,总孔容积变化不大；表面增加了Fe-O官能团；MELRBC饱和磁化率为16.12 emu g-1。(2) Cr (Ⅵ)吸附受磁化过程、溶液pH、共存离子、时间以及温度影响。MELRBC的Cr (Ⅵ)、TCr去除率相比活性炭有少量减少；溶液pH越低,Cr (Ⅵ)的去除率越高；共存Cu(Ⅱ)以及Ni (Ⅱ)离子的存在能促进Cr (Ⅵ)的吸附；MELRBC去除Cr(Ⅵ)的过程可以分为2个阶段：吸附的前30 min快速吸附阶段以及去除率缓慢增加并逐渐达到平衡阶段；温度的升高会延长吸附反应平衡时间,但能提高Cr (Ⅵ)的去除率。(3)磁性炭对Cr (Ⅵ)的吸附包含化学及物理吸附Freundlich以及Sips等温模型、伪二级动力学模型能较好地描述磁性炭去除Cr (Ⅵ) TCr的过程；磁性炭对Cr(Ⅵ)的吸附过程主要包括静电吸附、络合反应以及氧化还原作用。(4) MELRBC含量以及溶液pH会影响磁分离效果。为达到同一分离效果,混合液中磁性炭含量越大,所用的磁分离时间越长；溶液pH越低,磁分离效果越差,但当pH达到3以上时,磁分离受pH影响不再显著。(5) NaOH对负载Cr的吸附剂的脱附效果较好。240 min后,Cr (Ⅵ)以及TCr脱附率均达到80%以上,且无Fe溶出；增大NaOH浓度对脱附的影响不大；脱附最佳固液比(吸附剂/再生液)为160 g L-1。(6)MELRBC能有效处理高浓度的含铬电镀废水。Cr(Ⅵ)和总铬(TCr)的去除率均大于97%,其他共存离子几乎完全去除；磁分离10 min后,其混合液浊度为21.8 NTU；在与原吸附剂投加量相同的条件下,利用再生吸附剂处理电镀废水时,Cr(Ⅵ)以及TCr去除率仅少量降低,共存离子Ni (Ⅱ)、 Cu (Ⅱ)的去除率以及磁分离效果相差不大。
[Abstract]:The removal of pollutants from water by adsorption method has attracted much attention from many researchers.The practical application of traditional adsorbents (such as activated carbon) is limited because it is difficult to separate solid from treated wastewater.It is a relatively new field to apply magnetic adsorbent to remove pollutants in water. Using magnetic field to separate magnetic adsorbent has the advantages of saving time, low price, safety, high efficiency and so on.In this paper, the waste residue of eucalyptus leaves from a large number of cultivated eucalyptus leaves in Guangxi was extracted from eucalyptus oil, and magnetic activated carbon (Eucalyptus Leaf Residue Biocharr, MELRBC) was prepared by chemical coprecipitation method. It was applied to the removal of Cr ions in water. The factors affecting adsorption and the magnetic separation effect were investigated.The adsorption-magnetic separation technology was applied to the treatment of chromium-containing electroplating wastewater, and its application potential in the treatment of chromium-containing electroplating wastewater was preliminarily discussed.The main conclusions are as follows: 1) after magnetization, the physical and chemical properties of activated carbon are changed.The iron oxides formed by coprecipitation (mainly Fe304) were selectively distributed on the surface of activated carbon with an average particle size of 22 nm, the C content of activated carbon changed from 46.2% to 38.4%, the specific surface area and micropore volume decreased, but the mesoporous volume increased.The total pore volume changed little, the saturated magnetic susceptibility of Fe-O functional group Mel RBC was 16.12 emu g-1.2Cr (鈪，

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