【作者】 李锋；

【导师】 宋启军；

【作者基本信息】 江南大学 ， 分析化学， 2017， 硕士

【摘要】 一氧化氮(NO)作为一种神经递质和重要的信使分子,在人体的各种组织器官中广泛存在,并具有很强的生物活性,在病理生理过程等很多方面起着重要的作用。但是它也是室内空气污染物之一,即使低浓度的NO仍会危害人体健康。基于此,对室内低浓度NO进行准确测定及控制十分重要。NO与臭氧反应的化学发光检测法具有灵敏度高、响应快、线性范围宽、同时还可以实时、在线监测、而且检测限为0.5 ppb等优点,因此被广泛应用于NO的分析检测。然而,研究发现外来杂质气体对NO的化学发光检测有干扰作用,并且此干扰直接影响着NO检测结果的准确性。故研究外来杂质气体的干扰及消除对微量NO的精确测定起着关键的作用。同时,NO作为室内空气质量评判标准之一,室内NO的累积将对人体造成高铁血红蛋白症及中枢神经损害;NO与氧气反应生成的NO2对肺有较显著损害,因此研究适用于消除室内NO的催化剂也是十分必要且重要的领域。基于以上问题,本文的研究内容主要包括以下几个方面:首先,研究了在化学发光法测量低浓度NO时,外来挥发性气体对NO检测的干扰影响及消除干扰的方法。探究了氨气、苯乙烯、乙醇、乙醚、正己烷和甲苯对微量NO检测的干扰情况,其最低浓度分别达到:0.063 mg/m3、0.19 mg/m3、0.66 mg/m3、2.29mg/m3、3.78 mg/m3和5.62 mg/m3即对NO的检测有明显干扰。为了提高微量NO检测的准确度,分别选用不同的吸附材料对待测气体进行前处理,发现沸石分子筛、活性炭、NaA分子筛膜在除去杂质气体的同时吸附部分NO,而亲水改性分子筛能有效消除杂质气体且不会对NO的检测产生影响。因此,可以采用亲水改性分子筛作为前处理材料,对待测样气处理,再采用化学发光法检测NO的含量,进而提高检测NO的准确度。其次,选用化学发光法检测室内NO的累积情况。分别选择体积为3 m3、30 m3和70 m3空间模拟室内环境,探究不同人均空间对室内NO含量变化的影响。实验结果表明1人在3 m3空间55 min后,环境内NO的浓度为原来的1.9倍。随着停留时间的增长,经过210 min时NO的浓度为原来的3.3倍。随后考察人均空间分别为6 m3、10 m3、23m3以及12 m3时换气系统常开的条件下,化学发光法都可明显检测到室内NO的累积变化。最后研究了室内吸烟对NO浓度的影响,发现烟雾可导致NO的急剧增加。可见室内人体及其活动将会造成NO的累积,尤其吸烟产生的NO更多,所以为了提高室内环境空气质量要注意通风且减少烟气排放,同时此次探究也为人员密集场所的空气质量的评价提供依据,进而保护人体健康。NO作为室内空气污染物之一且低浓度时也易发生累积,将对人体健康造成危害。基于此,为了提高室内空气质量,我们研究了适用于室内催化消除NO的方法。分别探究不同方法合成的铜锰氧化物对NO的催化活性,其中沉淀法制得的催化剂对NO的催化活性较高,但产物为NO2仍会造成环境污染。而采用氢氧化钾浸渍处理制备的钾掺杂铜锰氧化物可有效消除室内NO,且产物为硝酸盐,属于一种环境友好型催化剂。随后探究了合成该催化剂的最佳条件:铜锰前驱物的摩尔比为1:2、pH调节剂为四甲基氢氧化铵和钾原子掺杂量为7.03%(7.4 mg/g)。钾掺杂铜锰氧化物不仅对NO的吸附性能有了很大的提高,而且促进了产物硝酸盐的形成,从而进一步提高了NO的消除率。该过程无NO2生成、不需要还原剂(NH3、H2、烷烃或尿素)、低温条件(265℃)时NO的消除率可高达99.9%、同时适用于高氧浓度氛围。钾掺杂铜锰氧化物是一种高性能的低浓度NO消除催化剂,在净化室内空气方面有着巨大的潜力。更多还原

【Abstract】 Nitric oxide(NO),as a neurotransmitter and an important messenger molecule,is widely existed in various tissues and organs of the human body.It has a strong biological activity and plays an important role in many aspects of pathophysiology.However,it is also one of the indoor air pollutants,even at low concentration,which will still endanger human health.Based on this,it is very important to determine NO concentration accurately and control the concentration in a suitable range.The chemiluminescence detection method based on the reaction of NO and ozone is high sensitive,fast responsive,with wide linear detection range.What’s more,it can be real-time,on-line monitoring,and the detection limit is as low as 0.5 ppb.So it is widely used in the analysis of NO detection.However,it has been found that when applying chemiluminescence method detecting NO,other impurity gas has a disturbing effect,and the interference directly affects the accuracy of the NO test results.Therefore,the study of other impurity gas interference and elimination it play a key role in the precise determination of trace NO.At the same time,NO as one of the indoor air quality evaluation standards,the accumulation of NO will cause methemoglobinemia and central nervous system damage in the human body.NO2 generated from NO and oxygen has a more significant effect on the lungs,so it is also necessary and important to explore the suitable catalyst,which is useful in the elimination of NO in the room.Based on the above problems,the main contents include the following aspects:Firstly,the effect of other volatile gases on the NO detection and the eliminating method of the interference were studied by chemiluminescence method when the low concentration of NO was measured.First of all,we studied the interference effects and the eliminating method of exogenous volatile gases on the trace NO detection through the chemiluminescence method.In this work,interference effects from volatile gases,such as ammonia,styrene,ethanol,ether,hexane and toluene were studied.And these organic compounds could impose serious interference to NO determination,when their concentrations were greater than 0.063 mg/m3,0.19 mg/m3,0.66 mg/m3,2.29 mg/m3,3.78 mg/m3 and 5.62 mg/m3,respectively.In order to improve the accuracy of NO analysis,different adsorbents were used to eliminate these volatile gases.Although volatile gases can be removed fully by zeolite molecular sieve,activated carbon and NaA molecular sieve membrane,part of NO is also absorbed simultaneously.In contrast,hydrophilic modified molecular sieve can effectively eliminate impurity gases and had little influence on NO determination.Therefore,hydrophilic modified zeolite can be used as the pretreatment material,and the content of NO can be detected by chemiluminescence after treatment.Therefore,the hydrophilic modified molecular sieve can be used as the pretreatment material to treat the sample gas,then improve the accurate determination of NO by chemiluminescence method.Secondly,the chemiluminescence method was used to detect the accumulation of NO in the room.The effects of different per capita space on the NO content in the room were investigated by simulating the indoor e nvironment of 3 m3,30 m3 and 70 m3,respectively.The experimental results showed that the content of NO in the environment increased in 1.9 times after 55 min in 3 m3 space.With the increase of residence time,the NO content was 3.3 times than the original concentration after 210 min.Then,the cumulative change of NO in the room can be detected by chemiluminescence under the condition that the per capita space is 6 m3,10 m3,23 m3 and the ventilation system normally open conditions in 12 m3,respectively.At last,the effect of smoking on NO content was studied,too.It was found that smoking could lead to a sharp increase in NO.It can be seen that the indoor body and its activities will cause the accumulation of NO,and the smoking will produce more N O,so in order to improve the indoor air quality we should pay attention to indoor ventilation and reduce the flue gas emissions.While the inquiry is also a personnel-intensive air quality assessment providing the basis for further protection of human health.NO as one of the indoor air pollutants and low concentration is also prone to accumulation,which is harmful to human health.Based on this,in order to improve the indoor air quality,we have studied the methods for indoor catalytic elimination of NO.The catalytic activity of the copper-manganese oxide synthesized through different methods on NO was investigated.Among them,the catalyst prepared by the precipitation method has higher catalytic activity,but the product of NO2 could cause environmental pollution.However,potassium-doped copper-manganese oxide prepared by potassium hydroxide impregnation treatment can eliminate indoor NO effectively and the product is nitrate,which belongs to an environment-friendly catalyst.The optimum synthesis co nditions were as follows: the molar ratio of copper and manganese precursors was 1:2 and the pH adjusting agent was tetramethylammonium hydroxide(TMAH),and the doping amount of potassium atom was 7.03%(7.4 mg/g).Potassium-doped copper-manganese oxide not only greatly improved the adsorption performance of NO,but also promoted the formation of nitrate,thereby further improving the NO elimination rate.The process does not produce harmful gas NO2 and no reducing agents(NH3,H2,alkane or urea)is required.In the low temperature conditions(265 °C),the elimination rate of NO is as high as 99.9% and it is also suitable in high oxygen concentration atmosphere.Therefore,potassium-doped copper-manganese oxide is a high-performance catalyst for low-concentration NO elimination,which has great potential in the purification of indoor air.更多还原