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室内空气污染对人类居住生活环境的影响日趋严重,据世界卫生组织估计,2016年全球有420万人因室内空气污染而过早死亡,相比之下,户外空气污染导致的过早死亡只有380万人[1]。糟糕的室内空气质量已成为全球第九大疾病风险负担[2]。室内空气的污染除室外污染空气的影响外,还与室内装修、人类活动以及室内家居用品等密切相关。随着人们健康意识的提高,空气净化器作为改善室内空气品质的一种有效途径,已逐渐成为室内空气净化的主要手段[3]。
目前市场上销售的空气净化器大都采用HEPA滤网过滤空气中的颗粒物,研究表明,HEPA滤网可以将颗粒物质量和颗粒物数浓度降低50%以上[4-7],技术相对成熟稳定。近年来,HEPA技术也一直占据着空气净化器市场的最主要份额[8-9]。相较于颗粒物的净化方式,对气态污染物的净化方式较多,但一直没有取得质的突破。较为主流的净化方式是应用改性活性炭制作成填充滤网或者夹炭复合布材料,整个过程中涉及到很多化学反应,如果选用的化学试剂不当,会将新的污染物引入到环境空气中,造成二次污染。近年来空气净化器在使用过程中出现酸臭异味的问题成为了消费者主要的投诉项目,这个酸臭异味也主要来源于活性炭滤网[10]。但由于各个厂商活性炭滤网的制作工艺及其中活性炭的改性配方各不相同[11-16],造成活性炭类滤网的性状差异较大,酸臭异味的成因来源一直没有明确的结论。
为了解决这一室内空气净化领域难题,本文通过感官评价与仪器分析相结合的方法对典型受试样本进行剖析[17-19],采用气相色谱-质谱、离子色谱及平板计数法测定了活性炭滤网中的挥发性有机物、有机酸、无机离子及菌落总数和霉菌等,并通过感官等级评价与不同成分的相关性分析,全面客观的对活性炭滤芯酸臭异味的成因及来源进行了探讨,为改善活性炭滤芯生产工艺与防治异味提供科学参考依据,以期促进空气净化器市场的持续健康发展。
室内空气净化器活性炭滤网酸臭异味特征及其来源解析
Characteristics and sources apportionment of sour odor in activated carbon filter of indoor air purifier
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摘要: 空气净化器在使用一段时间后会产生强烈的酸臭气味,严重影响消费者对产品的使用体验,为了考察酸臭异味的成因及来源,本研究首先采取感官等级评价得到存在酸臭异味的滤网样品特征,然后进一步通过气相色谱质谱、离子色谱等多种仪器手段从酸臭异味的角度对滤网样本进行剖析,结合感官等级评分进行相关性分析。结果表明,以乙酸为主的小分子有机酸可能是活性炭滤网酸臭异味的主要贡献者,根据文献调研推断很可能源于活性炭表面羧基基团脱落、常用催化剂的降解残留以及使用过程中的催化氧化。此外,低嗅阈值的微量化合物也可能是重要的气味贡献者之一。在实验研究的基础上,通过解析识别活性炭滤网潜在的气味来源和形成途径,以期为改善活性炭滤芯生产工艺与防治异味提供科学参考依据。Abstract: Air purifier will produce a strong sour odor after a period of use, which will seriously affect the use experience of consumers. In order to investigate the cause and source of the sour odor, this study first adopted sensory grade evaluation to obtain the characteristics of the filter samples with sour odor. Then, a variety of instruments such as gas chromatography-mass spectrometry and ion chromatography were further used to analyze the filter samples from the perspective of sour odor, and the correlation analysis was carried out by combining sensory grade scores. Results showed that small molecular organic acids, mainly acetic acid, may be the main contributors to the odor of activated carbon filter. According to the literature investigation, it can be inferred that the source is probably from the removal of the surface carboxyl group of activated carbon, the degradation of commonly used catalysts and the catalytic oxidation in the process of use. In addition, trace compounds with a low olfactory threshold may also be one of the important odor contributors. On the basis of the experimental study, the potential odor sources and formation pathways of activated carbon filter were identified, in order to provide scientific reference for improving the production process of activated carbon filter and preventing and controlling odor.
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Key words:
- air purifier /
- filter /
- sour odor /
- characteristics /
- source apportionment
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表 1 不同类型活性炭滤网样品
Table 1. Different types of activated carbon filter samples
样品编号
Sample number活性炭种类
Type of activated carbon产品类型
Product type是否改性
Modified or not是否用胶
Used glue or not使用情况
Usage condition1 椰壳炭+催化剂 柱状碳 是 否 6个月 2 煤制碳 柱状碳 是 是 6个月 3 煤制碳+催化剂 柱状碳 是 是 6个月 4 煤制碳+催化剂 柱状碳 是 是 6个月 5 煤制碳 柱状碳 是 是 6个月 6 煤制碳 柱状碳 是 是 未使用 7 煤制碳 柱状碳 是 是 未使用 8 煤制碳 柱状碳 是 是 未使用 9 煤制碳 柱状碳 是 是 6个月 10 煤制碳 柱状碳 是 是 6个月 11 椰壳炭 夹炭布 是 是 6个月 12 椰壳炭 夹炭布 是 是 6个月 13 椰壳炭 夹炭布 是 是 6个月 14 椰壳炭 夹炭布 是 是 6个月 15 椰壳炭 夹炭布 是 是 6个月 16 椰壳炭 夹炭布 是 是 未使用 17 椰壳炭 夹炭布 是 是 未使用 18 椰壳炭 夹炭布 是 是 未使用 19 煤制碳 柱状碳 是 否 6个月 20 煤制碳 柱状碳 否 否 6个月 21 椰壳炭 柱状碳 是 否 6个月 22 椰壳炭 柱状碳 否 否 6个月 23 煤制碳 柱状碳 是 是 6个月 24 煤制碳 柱状碳 是 是 6个月 表 2 滤网样品特征与感官评分的Spearman相关系数
Table 2. Spearman’s correlation coefficients between filters sample characteristics and sensory scores
样品特征Sample characteristics 感官评分Sensory evaluation 是否添加催化剂 0.558** 椰壳炭 −0.042 煤制炭 0.042 柱状炭 0.019 夹碳布 −0.019 是否改性 0.088 是否用胶 −0.060 是否使用过 0.559** **相关性在0.01置信水平下显著. **Correlation is significant at 0.01 level. 表 3 挥发性有机化合物的测定结果(µg·m−3)
Table 3. Determination results of the volatile organic compounds(µg·m−3)
化合物
Compound1号
Sample 12号
Sample 23号
Sample 34号
Sample 49号
Sample 911号
Sample 1119号
Sample 1920号
Sample 20环氧乙烷 3.21 10.18 5.28 7.76 1.55 2-甲基戊烷 5.62 3.03 5.16 1.65 4.97 3-甲基戊烷 12.22 9.02 11.39 6.35 2.11 12.72 正己烷 75.43 33.11 9.88 10.79 34.71 8.33 53.19 36.25 环己烷 10.68 5.66 8.84 3.86 6.24 4.40 庚烷 12.36 2.93 5.33 甲苯 17.58 11.41 8.55 24.37 6.06 19.15 30.38 乙酸丁酯 2.33 3.16 对、间二甲苯 9.32 6.76 3.15 2.10 8.31 4.88 1.55 环己酮 3.95 0.98 α-蒎烯 7.19 8.52 2.63 2.13 1.86 3-己醇 4.71 1.26 2.21 苯甲醛 6.10 3.24 1.75 癸烷 3.35 7.28 4.38 3.16 2.44 十六烷 9.26 11.33 5.66 6.12 3.43 表 4 感官气味与不同有机酸的相关性
Table 4. Correlation between sensory odors and different organic acids
感官气味
Sensory odor丙酸
Propionic acid甲酸
Formic acid丁酸
Butyric acid乙酸
Acetic acid乳酸
Lactic acid总酸
Total acid感官气味 1 丙酸 0.709** 1 甲酸 0.097 0.046 1 丁酸 0.167 −0.107 −0.134 1 乙酸 0.751** 0.888 0.126 −0.115 1 乳酸 −0.005 −0.063 −0.090 0.402 −0.011 1 总酸 0.712** 0.621** 0.115 0.610** 0.709** 0.285 1 **相关性在0.01置信水平下显著. **Correlation is significant at 0.01 level. 表 5 感官气味与不同阴离子的相关性
Table 5. Correlation between sensory odors and different anion
感官气味
Sensory odorCl− NO2− NO3− SO42- PO43- 总离子
Total ion感官气味 1 Cl− 0.376 1 NO2− −0.077 −0.072 1 NO3− 0.347 −0.017 −0.194 1 SO42- 0.037 −0.103 −0.230 0.059 1 PO43- −0.378 −0.301 −0.208 −0.220 −0.287 1 总离子 −0.315 −0.278 −0.316 −0.167 0.380 0.771** 1 **相关性在0.01置信水平下显著. **Correlation is significant at 0.01 level. 表 6 感官气味与总酸、总离子、pH值的相关性
Table 6. Correlation between sensory odour and total acid, total ion and pH value
感官气味
Sensory odor总酸
Total acid总离子
Total ionpH值
pH value感官气味 1 总酸 0.715** 1 总离子 −0.314 −0.017 1 pH值 −0.073 −0.151 −0.617** 1 **相关性在0.01置信水平下显著. **Correlation is significant at 0.01 level. 表 7 感官气味与菌落数及霉菌的相关性
Table 7. Correlation between sensory odour and colony number and mold
感官气味
Sensory odor菌落总数
Aerobic bacterial count霉菌
Mould感官气味 1 菌落总数 −0.234 1 霉菌 0.045 0.612** 1 **相关性在0.01置信水平下显著. **Correlation is significant at 0.01 level. -
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