溶剂浸泡对驻极体空气过滤材料性能的影响

通过过滤效率的跟踪测试,研究了聚丙烯熔喷非织造布驻极体空气过滤材料经各种不同溶剂浸泡后过滤性能的变化规律,比较了不同过滤效率测试方法对测试结果的影响。结果表明：溶剂浸泡后聚丙烯熔喷无纺布驻极体空气过滤材料的过滤效率都有不同程度的下降,下降幅度随水、甲醛、乙醇、异丙醇和丙酮的顺序逐渐增加,其下降规律与溶剂浸泡后滤材表面电位的衰减规律相一致,并与溶剂和聚丙烯分子间相互作用（溶胀作用）程度相关联。过滤效率对驻极体电场有很强的依赖性,其大小还与测试方法有关。     

羊毛滤料对PM2.5的过滤性能研究

从实验角度研究了羊毛滤料原样、经过纳米TiO2光催化整理后的整理样对PM2.5的过滤效率和阻力,并做了相关比较与分析。实验结果表明:随着风速的增大,相同克重的羊毛滤料对PM2.5的过滤效率逐渐降低,同时阻力大幅增加。随着克重的增加,羊毛滤料对PM2.5的过滤效率增大,过滤阻力也相应增大。经过纳米TiO2整理剂整理后,羊毛滤料整理样对PM2.5的过滤效率有所提高,但是阻力也有了相应的提高。     

静电模块对颗粒物与微生物的净化特性

为了检测空气净化器内静电模块在不同风速、不同湿度下对不同粒径颗粒物以及微生物去除效果,从而对其除尘性能影响因素的分析提供基础性的数据。研究测试了静电模块对PM 0.3、PM 1.0、PM 2.5、PM 10微细粉尘的净化特性及除菌效果。结果表明:在一定范围内,风速越大,则颗粒物衰减越快,当风速为0.5m/s时,衰减速率达到最大,再加大风速,颗粒物衰减的速率下降;当湿度越大时,颗粒物PM 0.3、PM 1.0、PM 2.5、PM 10去除效果下降,相同湿度时,颗粒物粒径越大,越容易去除。风速越高,静电模块除菌的效果越好。风速为0.1m/s时,90 min后,除菌率最终为94.06%,当风速为0.3 m/s、0.5 m/s、0.8 m/s时,除菌率最终可以达到99%。     

新型驻极体过滤材料性能测试分析与应用

通过对现用空调过滤材料和驻极材料进行性能对比测量,分析克重对过滤效率和阻力的影响,进而测量过滤材料和过滤器的性能差异、驻极材料的容尘性和“清洗”后效率,对驻极滤料的使用状况和应用前景进行探讨。     

不同滤网对颗粒物及真菌净化效果的试验研究

为优化空气净化器内不同过滤网组合的净化效率,增强空气净化器的过滤性能,测试了3种过滤网对PM0.3、PM1.0、PM2.5、PM10微细粉尘的净化特性及除菌效果。结果表明:对于不同过滤网,质量浓度与数量浓度得到的总衰减常数存在差异,且数量浓度得到的洁净空气量略大于质量浓度得到的洁净空气量。安装初效棉过滤网的空气净化器开启30 min后,微生物数量趋于稳定,除菌率最终为86.14%。对于HEPA高效过滤网,15 min后,微生物数量趋于稳定,除菌率最终为93.97%。对于活性炭过滤网,30min后,微生物数量趋于稳定,除菌率最终为53.13%。     

改性羊毛纤维滤料净化室内低浓度SO_2的研究

采用纳米TiO2改性羊毛纤维滤料来净化室内空气中的SO2。在实验中选用两浸两渍的方法制备纳米TiO2改性羊毛纤维,对整理后的羊毛纤维进行静态实验测试,并绘制吸附效果曲线图。实验测得"滤料1原样"对静态实验箱内SO2的净化率为9%,"滤料1整理样"对SO2的净化率为10%,紫外光灯照射后,"滤料1~5整理样"对SO2的过滤效率分别为53%、59%、60%、65%、71%。实验结果表明:无紫外光灯照射时,滤料整理前后对SO2的净化率相差不大。在紫外光灯照射下,滤料整理样对SO2的净化率呈几何型提高。     

基于大气消光系数概率分布参数的湿度订正方法

大气消光系数湿度订正是气溶胶吸湿性研究的重要内容,也是利用卫星气溶胶光学厚度(AOD)产品反演近地面颗粒物质量浓度的关键技术环节.基于成都市2016年1月至12月的逐时PM2.5质量浓度、大气能见度、相对湿度(RH)观测数据,首先,深入探讨了大气消光系数与颗粒物质量浓度之间的统计关系及其对RH变化的响应特征,发现在RH小于90％时,单位质量大气消光系数均服从对数正态分布,并进一步指出该分布函数的形状参数和尺度参数均随RH的增加呈现出波动型增长.其次,以干燥环境条件下(RH小于等于40％)单位质量大气消光系数对数正态分布参数为基准,通过数学变换消除湿度变化对单位质量大气消光系数概率分布参数的影响,据此提出了大气消光系数湿度订正的原理和计算流程.最后,对该原理的适用性进行研究,结果表明,订正后大气消光系数反演得到的PM2.5质量浓度与实际PM2.5质量浓度相关系数为0.90,显著优于气溶胶散射吸湿增长因子法的湿度订正结果.     

空气净化技术及其应用的对比分析

介绍了目前市场应用比较普遍的室内空气净化技术,包括物理过滤和化学去除微生物以及可挥发性气体的方法,同时也介绍了近年来世界各国在不同技术的专利发展方向和应用趋势;并基于目前国内市场上售卖的不同净化器产品所采用的技术和宣称的净化效率做了主要的特点分析和比较.     

应用T矩阵法对大气灰霾简单非球形粒子散射特性的计算与分析

针对灰霾天气条件下主要污染物粒子，PM2.5主要组分，以硫酸铵和碳质气溶胶粒子为典型粒子，运用T矩阵方法研究了这两种粒子不同形态的散射特性，包含椭球体（长短轴比a/b=1/2，1/3，2/1），圆柱体（直径与长度比D/L=1/2，1/3，1/1，2/1）及切比雪夫形（多项式n=2，形变参数=-0.1，0.1），两种粒子在不同形态下所对应的散射、消光及吸收效率因子随尺度参数的变化规律。结果表明，硫酸铵非球形粒子在尺度参数小于1时，不同形状粒子效率因子差异很小，从尺度参数大于1开始，散射、消光效率因子随尺度参数先增加后震荡减小，粒子吸收非常弱；而碳质气溶胶粒子在尺度参数小于2时，不同形状粒子效率因子差异很小，尺度参数大于2开始，各效率因子随尺度参数先增加然后缓慢减小，并且对光场具有较强的吸收作用。该研究结果可用于大气灰霾粒子探测分析，发展大气环境污染防护科技。     

基于二甘醇的气溶胶粒径谱仪在测量3 nm 以下颗粒物时的性能比较

近年来, 基于二甘醇的气溶胶粒径谱仪被广泛用于 3 nm 以下气溶胶颗粒物的粒径谱测量, 探究比较这些仪器 的性能对于粒径谱的准确测量有着重要的意义。对基于二甘醇的扫描电迁移率粒径谱仪 (DEG-SMPS) 和颗粒物粒径 放大器 (PSM) 进行了比较研究。在实验室标定过程中, 为让 PSM 获得更可靠的数据, 建议尽可能将标定范围设定至 大于 4 nm, 以减少 3 nm 以上的颗粒物在数据反演过程中的影响, 还可以增加 PSM 数据反演的粒径范围。研究表明, PSM 和 DEG-SMPS 在测量小于 3 nm 的颗粒物数浓度时, 结果较为一致。在外场观测的每个新粒子生成天, 这两种仪 器之间的数浓度相关性均很好 (r2 >0.75)。但 PSM 与 DEG-SMPS 总数浓度比值的斜率在 1.4 到 4.5 之间变化, 推测可 能是由于新粒子生成的颗粒物化学组分的不同导致的。此外, 一些不可忽略的不确定因素, 如两台仪器标定检测效 率所产生的不确定度以及 DEG-SMPS 使颗粒物带电时荷电效率的不确定度等, 也可能导致该比对结果的差异。由于 DEG-SMPS 使用静电气溶胶分级器 (DMA) 对颗粒物的粒径进行区分, 而 PSM 是通过改变二甘醇的过饱和度以激活 不同粒径的颗粒物, 进而通过数据反演来对粒径进行区分, 因此 DEG-SMPS 的粒径分辨率比 PSM 要高。但 PSM 在低 颗粒物数浓度的环境中表现更好, 包括一些较弱的新粒子生成天, 这是因为 PSM 不需要使颗粒物带电, 从而避免了 3 nm 以下颗粒物的极低的荷电效率的问题。因此相比于 DEG-SMPS, PSM 不容易受到凝聚核粒子计数器 (CPC) 的计数 误差带来的影响。总的来说, PSM 和 DEG-SMPS 都足以用于测量 3 nm 以下颗粒物的粒径谱分布, 有助于更好地进行 新粒子生成过程的研究, 结果中仍然存在的部分不可忽略的不确定性问题需要在未来的研究中进一步解决。     

微脉冲激光雷达系统实验观测及应用

针对大气气溶胶监测的迫切需要,研制完成了用于大气气溶胶光学特性和水平能见度测量的微脉冲激光雷达系统。本文主要介绍了该激光雷达系统的结构和主要技术参数,发射系统采用重复频率为2.5 kHz、单脉冲能量为6 μJ的半导体泵浦固体激光器,接收系统采用20 cm口径的施密特-卡塞格林式望远镜、0.5 nm的窄带干涉滤光片及光子计数模式的光电倍增管。利用本系统对青岛地区对流层的大气气溶胶进行了观测,观测结果表明,该系统具备连续观测对流层大气气溶胶的能力,可以很好地反映气溶胶粒子的时间和空间分布特征。     

High‐Efficiency Low‐Resistance Oil‐Mist Coalescence Filtration Using Fibrous Filters with Thickness‐Direction Asymmetric Wettability

Conventional aerosol filters typically have homogeneous wettability with limited filtration ability especially for small oil mists. Increasing filtration efficiency using thicker filter pad or finer fibers both result in considerable increase of pressure drop, which adversely increases energy consumption. It remains a challenge to develop effective filter materials that can effectively remove oil mists from air at a low flow resistance. Here, a novel concept about improving oil mist filtration efficiency without apparently increasing pressure drop using a fibrous filter with asymmetric wettability across the thickness is demonstrated. Dip‐coating and single‐side electrospraying are used to make fibrous filter have a homogeneous superoleophobicity or directional oil‐transport function. When the two are combined together, they show a filtration efficiency as high as 99.45% for small oil mists (size 0.01–0.8 µm) and nearly 100% for large oil mists (size 0.5–20 µm) with a pressure drop of 9.29 kPa. With the same thickness and fibrous structure, our directional oil‐transport/superoleophobic filter has higher quality factor than those with homogeneous oleophilic, superoleophobic, and asymmetric wettability of other superoleophilic/superoleophobic combinations, for both small and large oil mists. Directional oil transport‐superoleophobic filters may lead to a novel, high‐performance, low energy consumption oil mist separation technology.     

Electrically Activated Ultrathin PVDF‐TrFE Air Filter for High‐Efficiency PM1.0 Filtration

Ultrafine particulate matter (PM) in indoor air has become a serious concern for public health. Therefore, there is a growing interest in filters that can be installed on the window frames of ordinary homes to improve the indoor air quality by natural passive ventilation without using expensive forced air circulation systems. Thus, these filters require a high filtering efficiency and high air permeability and visibility, which do not compromise the original functionality of the windows. The filters developed for this purpose to date have demonstrated a high filtering efficiency for PM_2.5 but a relatively low efficiency for PM_1.0. Here, the performance of the ultrathin poly[(vinylidenefluoride‐co‐trifluoroethylene) (PVDF‐TrFE) nanofiber air filter capable of high‐efficiency PM_1.0 filtration is reported. To enhance the PM_1.0 filtering efficiency, the filter is electrically activated by the polarization of dipoles and triboelectrification using the ferroelectric nature and triboelectrically negative property of the PVDF‐TrFE filter layer. The electrically activated PVDF‐TrFE filter demonstrates a PM_1.0 filtering efficiency of over ≈88% after polarization, which is further improved to ≈94% after triboelectrification. In addition, the filter is ultrathin and air‐permeable with 65% light transmittance. The methods introduced in this work can be adopted to develop high performance, highly visible, and air‐permeable filter media.     

High‐Performance PM0.3 Air Filters Using Self‐Polarized Electret Nanofiber/Nets

Particulate matter (PM) pollution in air is thought to be an important mortality risk factor globally. Most existing air filters face the extreme challenge of effectively removing PM_0.3, which has the most penetration particle size (MPPS) of ≈0.3 µm yet is particularly harmful. Here, an innovative in situ electret electrospinning/netting technique that can manipulate both solution phase separation and crystal phase transition is reported to develop self‐polarized polyvinylidene fluoride nanofiber/net membranes with 2D networks and superior surface adhesion. By combining the true nanoscale diameter (≈21 nm), small pore size (≈0.26 µm), and highly electret surface (6.8 kV potential) of the 2D nanonets, the synergistic effect of sieving and adhesion for MPPS PM_0.3 is achieved. Such double capture characteristic enables the high‐efficiency (≈99.998%) capture of PM_0.3 while maintaining low air resistance (≈0.1% atmosphere pressure). Moreover, the nanofiber/net filters show integrated properties of superhydrophobicity, desirable transparency (91%), and long‐term stability. The synthesis of such attractive nanomaterials presents a promising attempt toward the development of high‐performance filtration/separation materials for numerous applications.     

用光学粒子计数器测颗粒物质量浓度和能见度

2001年夏季和冬季，在北京市大兴区榆垡镇，利用光学粒子计数器、能见度仪和颗粒物质量监测器对近地面大气气溶胶粒子数密度、大气能见度、颗粒物质量浓度(PM10、PM2．5和PM1．0)等进行了联合观测实验，取得了大量相关资料．本文通过对不同尺寸大气气溶胶粒子的数密度与颗粒物质量浓度及大气能见度的多元线性回归分析，给出了利用粒子数密度计算PM10、PM2．5、PM1．0和大气能见度的经验计算公式．     

Washable Multilayer Triboelectric Air Filter for Efficient Particulate Matter PM2.5 Removal

Efficient removal of particulate matter (PM) is the major goal for various air cleaning technologies due to its huge impact on human health. Here, a washable high‐efficiency triboelectric air filter (TAF) that can be used multiple times is presented. The TAF consists of five layers of the polytetrafluoroethylene (PTFE) and nylon fabrics. Compared with traditional electrostatic precipitator, which requires a high‐voltage power supply, the TAF can be charged by simply rubbing the PTFE and nylon fabrics against each other. The electrical properties of the TAF are evaluated through the periodic contacting–separating of the PTFE and nylon fabrics using a linear motor, and an open‐circuit voltage of 190 V is achieved. After charging, the TAF has a removal efficiency of 84.7% for PM_0.5, 96.0% for PM_2.5, which are 3.22 and 1.39 times as large as the uncharged one. Most importantly, after washing several times, the removal efficiency of the TAF maintains almost the same, while the commercial face mask drops to 70% of its original efficiency. Furthermore, the removal efficiency of the PM_2.5 is very stable under high relative humidity. Therefore, the TAF is promising for fabricating a reusable and high‐efficiency face mask.