改性活性炭对VOCs吸附能力的研究

发布时间：2018-04-03 02:11

  本文选题：VOCs　切入点：活性炭改性　出处：《西南交通大学》2017年硕士论文

【摘要】：家具涂装业是VOCs主要的工业源之一,其VOCs处理工艺也越来越受到重视。吸附工艺是家具涂装业最主要的VOCs处理工艺,活性炭是最常用的吸附剂。吸附处理工艺具有净化效率高、设备简单等优点。但是,吸附工艺中仍存在诸多问题需要改进,如吸附剂量大、定期更换等。如何提高吸附剂的吸附性能成为降低吸附工艺的成本的主要措施。本文通过硝酸改性、氢氧化钠改性、高温改性方法改性活性炭,采用Boehm滴定法测定了改性活性炭表面含氧官能团的含量,并研究了改性后活性炭对甲苯的吸附性能。研究结果如下:(1)Boehm滴定实验:硝酸改性活性炭表面酸性基团增加,碱性基团减少,表面酸性基团比重增大。氢氧化钠改性活性炭表面酸性基团减少,碱性基团没有明显变化,表面碱性基团比重增加。酸碱改性活性炭表面含氧基团都随着改性液的浓度增大变化量的越大。高温改性活性炭表面酸性基团随着温度的增大逐渐减少,碱性基团逐渐增加,同样表面碱性基团比重增加。(2)活性炭静态吸附实验:硝酸改性与氢氧化钠改后性活性炭对甲苯的吸附饱和量没有明显变化;高温改性后活性炭随着改性温度升高对甲苯的吸附饱和量增加,800℃时达到195 mg/g。(3)活性炭吸附动态实验:原活性炭吸附穿透时间为120min,20%硝酸改性和800℃高温改性活性分别推迟30 min和60 min。(4)吸附床高度的不同影响吸附穿透时间的不同,随着吸附床层高度的增加,穿透时间相应增大。根据希洛夫公式两者呈线性关系,经拟合得出800℃改性活性炭的穿透作用系数K=25.5 min/cm,吸附穿透时间损失t_0=110 min。
[Abstract]:The furniture coating industry is one of the main industrial sources of VOCs, and its VOCs treatment technology has been paid more and more attention.Adsorption process is the most important VOCs treatment process in furniture painting industry, activated carbon is the most commonly used adsorbent.Adsorption treatment process has the advantages of high purification efficiency and simple equipment.However, there are still many problems in adsorption process, such as large amount of adsorbent, regular replacement and so on.How to improve the absorbability of adsorbent is the main measure to reduce the cost of adsorption process.In this paper, the modified activated carbon was modified by nitric acid, sodium hydroxide and high temperature. The content of oxygen functional groups on the surface of modified activated carbon was determined by Boehm titration, and the adsorption property of modified activated carbon to toluene was studied.The results are as follows: the surface acidic group of activated carbon modified by nitric acid increases, the basic group decreases, and the specific gravity of surface acidic group increases.The surface acidic group of activated carbon modified by sodium hydroxide decreased, but the basic group did not change obviously, and the specific gravity of surface basic group increased.The surface oxygen groups of acid-base modified activated carbon increased with the increase of the concentration of the modified solution.The surface acidic group of high temperature modified activated carbon decreases gradually with the increase of temperature, and the basic group increases gradually.At the same time, the specific gravity of basic group on the surface increased. 2) the static adsorption experiment of activated carbon: the saturated amount of toluene adsorbed by activated carbon modified by nitric acid and sodium hydroxide did not change obviously;Adsorption of toluene by activated carbon at 800 鈩，

本文编号：1703150