活性碳纤维改性及其甲醛吸附特性研究

发布时间：2018-05-26 19:07

本文选题：粘胶基活性碳纤维 + 改性　；参考：《山东大学》2017年硕士论文

【摘要】：活性碳纤维(Actived carbon fiber,简称ACF)是在活性炭技术和碳纤维技术相结合的基础上发展起来的新一代高效吸附材料,具有比表面积大、微孔含量大、表面官能团丰富等结构特性,吸附能力强。甲醛是一种常见室内有机污染气体,平面形极性分子,气态甲醛分子直径约为0.45nm。本文以粘胶基活性碳纤维为研究对象,研究了不同方法改性活性碳纤维的结构特征及甲醛吸附性能:采用二次活化工艺、乙二胺接枝处理对活性碳纤维进行改性,分别对活性碳纤维甲醛吸附性能的主要影响因素—孔隙结构和表面官能团进行研究;此外,采用纳米二氧化钛、纳米银进行催化剂负载,制备了同时具有甲醛净化能力和抑菌能力的VACF/TiO_2复合材料和VACF/Ag复合材料。本文首次提出了功率超声改进的新型二次活化工艺,当活化剂采用磷酸、氯化锌、过氧化氢、硝酸时,新型二次活化工艺可更好的改善VACF表面结构。二次活化后VACF的比表面积、总孔容、微孔孔容均增大,平均孔径减小,微孔的孔径分布更为均匀。超声浸渍为12h时,采用不同活化剂二次活化处理的VACF表面物理结构参数的大小关系为:比表面积H-VACFZ-VACFN-VACFP-VACFVACFO,总孔容积 H-VACFZ-VACFP-VACFN-VACFVACFO。VACF二次活化后表面含氧基团含量增大,表面含氧基团种类主要有羟基、羰基、羧基等,含氧基团相对含量大小顺序为:羟基羧基羰基。新型二次活化工艺对VACF的吸附能力具有明显的提高作用。碘吸附值大小顺序为 P-VACFZ-VACFN-VACFH-VACFVACFO;处理浓度为 1mg/m~3的甲醛气体时,甲醛净化率大小顺序为P-VACFH-VACFZ-VACFN-VACFVACF0,其中磷酸二次活化的VACF甲醛吸附效果最好,甲醛净化率和平衡时甲醛吸附量分别为68.93%、5.11mg/m~2。通过乙二胺(EDA)接枝处理VACF的方法制备氨基化粘胶基活性碳纤维VACF-EDAx。VACF-EDAx的甲醛吸附能力随EDA处理浓度的增大呈现先增大后减小的趋势,在EDA处理浓度为0.5mol/L时,甲醛净化率、达到吸附平衡时甲醛吸附容量、吸附速度等性能均最佳。单位体积用量为0.14rrm~2/m~3的VACF-EDA0.5处理3mg/m~3浓度的甲醛气体时,用时28min即可完成100%甲醛气体的净化,实际甲醛吸附量为22.0mg/m~2。达到吸附平衡时甲醛吸附容量的Bolzman拟合预测值为29.30mg/m~2,Bolzman预测值相比VACFO的甲醛吸附容量提高了 91.50%。通过红外光谱和X射线光电子能谱的分析证明了 EDA接枝过程中主反应为乙二胺与活性碳纤维的表面羧基反应生成酰胺基团,副反应主要是伯胺基或仲胺基的离子化反应。喷涂工艺制备的VACF/TiO_2复合材料、VACF/Ag复合材料中,VACF的吸附作用能与纳米TiO_2、纳米Ag的催化作用产生协同效果,都具备良好的甲醛吸附性能和抑菌性能,其甲醛吸附性能都随催化剂负载率的增大呈现先增大后减小的趋势。VACF/TiO_2复合材料中VACF-3.57%TiO_2甲醛净化能力最好,1mg/m~3甲醛浓度下甲醛净化率为79.61%,达到吸附平衡时甲醛吸附量为5.90mg/m~2,对大肠杆菌、金黄色葡萄球菌的抑菌率分别为96%和98%。VACF/Ag复合材料中VACF-2.38%Ag甲醛净化能力最好,1mg/m~3甲醛浓度下甲醛净化率为79.61%,达到吸附平衡时甲醛吸附量为5.90mg/m~2,对大肠杆菌、金黄色葡萄球菌的抑菌率均大于99%。
[Abstract]:Actived carbon fiber (ACF) is a new high efficiency adsorption material developed on the basis of the combination of activated carbon technology and carbon fiber technology. It has large specific surface area, large micropore content, rich surface functional groups and so on. It has strong adsorption capacity. Formaldehyde is a common indoor organic pollution gas and plane pole. The molecular diameter of the molecular and gaseous formaldehyde is about 0.45nm.. In this paper, the structure characteristics of the modified activated carbon fibers and the adsorption properties of the modified activated carbon fibers are studied in this paper. The adsorption properties of active carbon fibers are modified by the two activation process. The main influencing factors, pore structure and surface functional group, are studied. In addition, nano titanium dioxide and nano silver are used to load the catalyst, and the VACF/TiO_2 composites and VACF/Ag composites with the ability to purify the formaldehyde and the bacteriostasis are prepared. In this paper, a new two activation process, which is improved by power ultrasound, is first proposed. When the activator uses phosphoric acid, zinc chloride, hydrogen peroxide and nitric acid, the new two activation process can better improve the surface structure of VACF. After two activation, the specific surface area, the total pore volume, the pore volume of the micropore are increased, the average pore size decreases and the pore size distribution is even more uniform. When the hyper acoustic impregnation is 12h, the V of two activation treatments of different activators is used. The relation between the physical structure parameters of ACF surface is as follows: the specific surface area H-VACFZ-VACFN-VACFP-VACFVACFO, the total pore volume H-VACFZ-VACFP-VACFN-VACFVACFO.VACF two times the oxygen group content increases, the species of oxygen group on the surface are mainly hydroxyl, carbonyl, carboxyl group, and the order of oxygen group relative content is the hydroxyl carboxyl group. The new two activation process has obviously improved the adsorption capacity of VACF. The order of iodine adsorption value is P-VACFZ-VACFN-VACFH-VACFVACFO. When the formaldehyde gas is 1mg/m~3, the order of formaldehyde purification rate is P-VACFH-VACFZ-VACFN-VACFVACF0, and the two activated VACF formaldehyde adsorption effect is the best, and the formaldehyde is net. The adsorption capacity of formaldehyde at the rate and balance was 68.93%, respectively, and 5.11mg/m~2. was prepared by grafting ethylene diamine (EDA) to VACF to prepare the formaldehyde adsorption capacity of the aminated viscose based active carbon fiber (VACF-EDAx.VACF-EDAx), which increased first and then decreased with the increase of EDA concentration. When the concentration of EDA was 0.5mol/L, the formaldehyde purification rate was reached. The adsorption capacity and the adsorption rate are the best when the adsorption equilibrium is balanced. When the unit volume is 0.14rrm~2/m~3 VACF-EDA0.5 for the 3mg/m~3 concentration of formaldehyde gas, the 100% formaldehyde gas can be purified by 28min. The actual formaldehyde adsorption capacity is 22.0mg/m~2. to the Bolzman fitting prediction of the adsorption capacity of the formaldehyde. The value of Bolzman is 29.30mg/m~2, compared with VACFO, the adsorption capacity of formaldehyde is increased by 91.50%. through the analysis of IR and X ray photoelectron spectroscopy. It is proved that the main reaction in the EDA grafting process is the reaction of ethylenediamine and the carboxyl group of active carbon fiber to produce amide groups, and the secondary reactions are mainly ionized reactions of primary amine or secondary amines. In the VACF/TiO_2 composites and VACF/Ag composites prepared by spraying process, the adsorption of VACF can produce synergistic effect with the catalysis of nano TiO_2 and nanoscale Ag. All of them have good formaldehyde adsorption and bacteriostasis performance. The adsorption properties of formaldehyde all increase first and then decrease with the increase of the catalyst load rate. The purification ability of VACF-3.57%TiO_2 formaldehyde in the composite was the best. The formaldehyde purification rate was 79.61% under the concentration of 1mg/m~3 formaldehyde. The adsorption amount of formaldehyde was 5.90mg/m~2 when the adsorption equilibrium was reached. The bacteriostasis rate of Escherichia coli and Staphylococcus aureus was 96% and the VACF-2.38%Ag formaldehyde in the 98%.VACF/Ag composite material was the best, and the 1mg/m~3 formaldehyde concentration was the best. The removal rate of formaldehyde was 79.61%, the adsorption capacity of formaldehyde reached 5.90mg/m~2 when the adsorption equilibrium was reached, and the inhibition rates to Escherichia coli and Staphylococcus aureus were greater than 99%.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424

【相似文献】