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毕业论文网 > 毕业论文 > 材料类 > 材料化学 > 正文

活性炭去除室内污染气体的综合评价毕业论文

 2021-05-11 09:05  

摘 要

室内气体污染严重威胁人类健康,导致头疼、咽炎、肺气肿等一系列症状,甚至癌症。目前去除室内污染气体的主要方法包括吸附法、催化氧化法、光催化法等。其中,吸附法具有去除效率高、成本低、工艺成熟、无二次污染等优点,被认为是去除室内污染气体的一种最简单易行的方法。常见的吸附剂包含活性炭(AC),活性氧化铝(AA)、沸石等。由于其具有丰富的微孔、大的比表面积,活性炭和活性氧化铝已经广泛运用于室内空气净化。由于当前对活性炭和活性氧化铝的吸附性能评估通常仅针对单一气体,且评价方法所用气体浓度远高于室内浓度,因此对活性炭和活性氧化铝针对低浓度下多种气体的吸附能力仍然不甚清楚。

由此本论文选取商业活性炭(AC)和活性氧化铝(AA)为吸附剂,以二氧化硫(SO2)为代表的酸性无机污染气体、以甲醛(HCHO)为代表的挥发性有机污染气体(VOC)和以氨气(NH3)为代表的碱性无机污染气体为吸附质,研究活性炭和活性氧化铝对不同吸附质气体在近似实际室内环境下的吸附性能,并对影响吸附性能的因素进行了探讨。

结果表明二氧化硫、甲醛、氨三种气体中活性炭对二氧化硫吸附效果最好,且活性炭微孔容量与吸附性能呈现正相关关系,同时我们利用氢氧化钾(KOH)改性活性炭、高锰酸钾(KMnO4)改性氧化铝和磷酸(H3PO4)改性氧化铝,发现其分别对二氧化硫、甲醛和氨气有显著增强的去除效果。综合去除室内污染气体需综合考虑改性吸附剂,合理利用并选择不同的吸附剂。

关键词:活性炭;活性氧化铝;二氧化硫;甲醛;氨气

Abstract

The severe indoor air pollution has become a big issue nowadays, and brougth great threat to human health. A series of symptoms, such as headache, pharyngitis, emphysema, even cancer, are thought to be derived from the poor indoor air condition. Currently, the widely used methods to purify the indoor gaseous pollutant are based on the principle of physical absorption, catalysis oxidation and photo-catalysis. And adsorption is one of the most simple and effective method to remove the indoor polluted air from indoor air because of its advantages of high removal efficiency, cost-effectiveness, mature technology, no secondary pollution and so on. Activated carbon (AC) and activated alumina (AA) have widely been used as adsorbent to remove malodorous and hazardous due to their abundant micro-pores and large surface area. In particular, the activated carbon is considered to be the most promising adsorbent. And the common adsorbents are the activated carbon (AC), activated alumina (AA) and zeolite. Since it has abundant micro-pores, large specific surface area, activated carbon and activated alumina have been widely used in indoor air purification area. However due to the adsorption performance evaluation of activated carbon and activated alumina is usually conducted in such conditions where the pollutant contains only one kind of gas, and the concentration of the pollutant is much higher than the actual indoor concentration, therefore, the specific adsorption performance of activated carbon and activated alumina in low concentration is still unclear.

In this thesis, commercial activated carbon (AC) and activated alumina (AA) were selected as adsorbents for sulfur dioxide (SO2), formaldehyde (HCHO) and ammonia (NH3), which represent the typical contaminants for inorganic acid, volatile organic compound (OVC) and inorganic basic in air pollutants. We investigate the adsorption performance of activated carbon and activated alumina on these three kinds of air pollutants, and compare the difference in adsorption ability of the adsorbents. Furthermore, the factors that influence the adsorption ability are studied and the results are summaried.

Our data shows that the adsorption of sulfur dioxide on activated carbon works the best, and we find that the adsorption capacity of the activated carbon is derived from its micropore volume as these two factors show a linear relation. At last, the adsorption performance of modified activated carbon using the potassium hydroxide, modified activated alumina using the potassium permanganate and phosphoric acid indeed shows improved adsorbability on sulfur dioxide,formaldehyde and ammonia. In order to completely remove indoor pollution gas, comprehensive consideration about the adsorbent modification and reasonable combination of different adsorbent need to be taken into account.

Key Words: Activated carbon; Activated alumina; Formaldehyde; Sulfur dioxide; Ammonia

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 室内污染气体的来源及危害 1

1.2 室内污染气体现状 2

1.3 室内污染气体去除方法 3

1.4 活性炭性质 4

1.5 活性氧化铝性质 7

1.6 论文研究的目的及内容 7

第2章 实验部分 9

2.1 主要试剂及样品 9

2.2 实验过程 11

第3章 结果与分析 17

3.1 材料表征结果 17

3.2 活性炭不同气体吸附结果与分析 18

3.3 活性炭孔径结构对SO2气体吸附性能的影响 19

3.4 未改性活性炭和改性活性炭对SO2吸附性能的影响 20

3.5 改性活性氧化铝对甲醛吸附性能的影响 21

3.6 改性活性氧化铝对NH3吸附性能的影响 23

第4章 结论与展望 24

4.1 结论 24

4.2 展望 24

参考文献 25

致 谢 29

第1章 绪论

随着人们生活水平的不断改善与提高,人们对居住、生活的室内环境的质量要求亦与日俱增,但装修材料和装饰材料美化室内环境的同时,也造成严重的室内空气污染。人们每天大多数时间都是于室内度过,包括生活、学习、工作、娱乐和休息等。特别地,幼儿和老弱病残者在室内的时间更长。此外,室内主要污染物的室内浓度明显高于室外,因此室内空气中污染气体含量的高低直接影响人类的身体健康[1]。如何控制及降低室内污染气体浓度也是目前的一个研究热点。

1.1 室内污染气体的来源及危害

我国现今农村还有许多是以烧煤为主的农户,但由于炉灶结构的不合理,煤并不能完全燃烧,导致大量污染气体排出,其中以二氧化硫为主[2]。同时,由于汽车尾气等排放大量二氧化硫气体,通风换气时室外二氧化硫气体进入室内,也是室内SO2的来源之一。此外吸烟过程中也会产生二氧化硫气体,造成室内二氧化硫浓度增加。作为无机酸性污染气体的典型气体,二氧化硫具有强烈辛辣刺激性气味,吸入后会灼烧粘膜发生气管炎、咽喉炎、鼻腔炎等[3]。二氧化硫主要通过呼吸道系统进入人体,与呼吸器官作用,造成或加重呼吸器官的疾病,且对人体呼吸道粘膜具有强烈辛辣刺激性,吸入后导致支气管炎等症状,严重者有肿水肿和呼吸麻痹等危险[4]。此外,室内二氧化硫气体与室外大气通风换气污染大气,大气中二氧化硫气体导致酸雨、植被破坏、建筑和遗址腐蚀等环境问题[5-7]

甲醛作为一种挥发性有机气体(VOC)在医学领域的消毒和灭菌特性被众所周知。其化学性能同时被应用于许多其他工业,如在纺织行业甲醛是合成各种树脂的常见前驱体[8]。甲醛作为最简单、最常见的挥发性有机物之一,具有强烈的刺激性,沸点为-21 °C[9]。家庭室内甲醛的主要来源于各种建筑材料和装饰材料[9][10]-11]。装修材料及家具中的胶合板等的粘合剂遇热、潮解时释放甲醛,致使室内甲醛浓度增加,这无疑是室内甲醛最主要的来源;此外,室内甲醛来自室外空气的污染,如工业废气、汽车尾气等排放或产生的甲醛进入室内,成为室内甲醛气体的来源之一[2]。甲醛是高毒性的挥发性有机气体。目前,所有医疗当局确认人和动物长期暴露于甲醛下会导致癌症[8],[12]。长期接触甲醛的人,会得皮肤等疾病。即使是甲醛浓度相当低,如果人们长期暴露于此,也会带来哮喘、湿疹的风险[13]。甲醛浓度与人体反应关系如表1.1所示。

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