超细无碱玻纤复合滤料的过滤性能

袋式除尘是一种高效的除尘技术,对PM_(2.5)具有较高的过滤效率,但是其运行阻力较大,因此,研发高效、低阻过滤材料是解决大气污染问题的关键所在。以耐高温的PPS纤维针刺布为上下层,超细无碱玻纤为中间层,经过超声波粘合或线缝合技术制备了多层复合过滤材料,研究了滤料在容尘状态下的过滤效率、过滤阻力,以及孔径变化。结果表明,该复合滤料的初始阻力低于150 Pa,容尘后对0.2~2μm的颗粒物的过滤效率达80%以上;随着粉尘的沉积,滤料的过滤效率有了较大提高,对1μm以上颗粒物的过滤效率可达99.99%以上,对最易透过粒径(MPPS)的过滤效率达95%以上;过滤前后,滤料的孔径分布发生了变化,过滤后滤料出现了1~5μm的孔径分布。该复合滤料在工业高温粉尘过滤中将会有较好的应用前景。     

家居环境PM_(2.5)控制用空气滤料

针对目前家居环境净化PM2.5的要求,在现有空气过滤材料的基础上,探讨一种适合于家居环境移动式空气净化装置用低阻、高效和长寿命的过滤材料。采用实验研究的方法对常用玻纤滤纸以及驻极体空气过滤材料进行了过滤特性、电镜、孔径测试的对比实验研究。结果表明,当过滤风速为5 cm/s时,3种驻极体滤料对粒径≤4.5μm的颗粒物的分级过滤效率要高于玻纤滤纸且都在90%以上,其过滤阻力在4.9~6.4 Pa之间,而高效滤纸的过滤阻力在57.8~78.6 Pa之间;在实验风速条件下,驻极体滤料对PM2.5的过滤效率和过滤阻力分别高于和低于高效玻纤滤纸;对驻极体滤料进行蒸馏水洗涤后,其对颗粒物的过滤效率下降,驻极体滤料静电效应具有不稳定特性;电镜测试发现,玻纤滤纸纤维层排布致密,纤维存在断裂现象,而驻极体滤料较为蓬松,无纤维断裂现象;孔径实验表明,驻极体滤料的平均孔径为玻纤滤纸的11.9~14.7倍,驻极体滤料具有良好的透气和容尘特性。     

改性锰砂滤料处理高铁锰煤矿矿井水

采用KMnO4溶液浸渍法制备了新型改性锰砂滤料,研究了滤料表面性能和过滤处理高铁锰矿井水的效果。结果表明,锰砂滤料除铁锰性能优于石英砂、陶粒以及瓷砂,采用KMnO4溶液浸渍能够提高锰砂滤料的过滤性能,最优的浸渍浓度为5%。5%KMnO4改性锰砂滤料过滤处理高铁锰矿井水的最佳工艺参数为：过滤周期24 h,反冲洗强度3.2 L/（s.m2）,反冲洗时间5 min;通过比表面积测试分析和SEM表征分析发现,KMnO4溶液浸渍能够提高锰砂滤料比表面积,并在锰砂滤料表面形成了氧化膜,从而提高除铁除锰效果,而且浸渍液浓度越高,这种作用越明显。     

电解铝用滤袋缝合工艺对PM_(2.5)过滤效率的影响

针对常用涤纶滤料,分别采用不同道数的缝纫线缝合和在缝纫接口处的针孔上涂胶等不同的缝合工艺,实验测试并对比了涤纶滤料在不同的缝合工艺下的静态过滤效率,并讨论了滤袋缝合工艺对PM2.5过滤效率的影响。结果表明,清洁滤料在环境气溶胶中,缝纫线缝制道数越多,过滤效率就越低,每增加一道缝纫线过滤效率就降低1%~6%左右;采用胶合工艺将滤袋缝合处的针孔涂胶覆盖,对于粒径大于1μm以上的颗粒物的过滤效率有明显提高,最大提高值达7%;温度对胶合后的缝纫接口影响较小,过滤风速对过滤效率和过滤阻力影响较大。     

电袋复合除尘器阻力特性研究

利用电袋复合除尘器试验平台,探讨了清洁滤料过滤阻力特性、电场与过滤风速对过滤阻力的影响及本体阻力与测试风量的关系。结果表明:清洁滤料过滤阻力与过滤风速成线性关系,滤料阻力系数为5.39×10~7 m~(-1);无电场作用下,过滤阻力增长率为2.31Pa/min;而65kV电场作用下,过滤阻力增长率仅为0.63Pa/min,主要因为在电场作用下,颗粒层渗透率增大,且荷电粉尘在滤料表面排列疏松,空隙较多,过滤阻力增加慢,可以有效延长喷吹时间,减少喷吹过程对滤袋的冲刷;过滤阻力增长率随过滤风速的增加而增加,过滤风速由0.65m/min增加到0.97m/min,过滤阻力增长率由0.13Pa/min增加到0.63Pa/min;电袋复合除尘器本体阻力(ΔP,Pa)和测试风量(Q,m~3/s)的拟合方程为ΔP=72.15Q~2+25.07Q。     

超高温烟尘过滤陶瓷滤料的制备

以硅酸铝纤维和莫来石纤维为主体材料,纳米二氧化硅作为高温陶瓷黏结剂,制备出一种适用于800℃下直接过滤的除尘滤料。研究了纳米二氧化硅添加量和烧成温度对多孔陶瓷过滤材料性能的影响,通过TG-DSC确定纳米二氧化硅的熔融温度,利用SEM表征材料的纤维粘结情况和孔隙结构。结果表明,纳米二氧化硅添加量为3%,烧成温度为1 300℃时,制备出的材料性能较佳,抗折强度为4.96 MPa,过滤阻力为139 Pa(过滤风速为1 m/min),气孔率为80%。     

双层滤料颗粒床与金属纤维毡梯级过滤特性

为了提高双层滤料颗粒床对亚微米粉尘的过滤效率,进行了双层滤料颗粒床与金属纤维毡梯级过滤实验研究。结果表明:不加金属纤维毡的双层滤料颗粒床的过滤效率为96.35%、出口粉尘浓度为85.5 mg?m~(-3)、总压降为1 840 Pa;加金属纤维毡时,双层滤料颗粒床与金属纤维毡梯级过滤的总过滤效率为99.13%、出口粉尘浓度为19.8 mg?m~(-3)、总压降为1 730 Pa。双层滤料颗粒床与金属纤维毡梯级过滤大幅度地降低了出口粉尘浓度;并且由于金属纤维毡替代了稳流层,还降低了总压降。     

粉煤灰基陶瓷微滤膜处理水中悬浮物的抗污染特性

粉煤灰基陶瓷微滤膜是一种新型的廉价无机膜,为研究其抗污染性能,研究了自制的管式膜在处理几种典型料液中的分离性能和渗透性能.考察了过滤不同料液过程中的阻力构成和膜的抗污染特性,并且和文献报道的同类过程中其他膜材料的性能进行了比较.实验进行了2～45 h无反冲、无清洗的连续运行.在过滤粉煤灰悬浮液、高龄土悬浮液和斜生栅藻悬浮液过程中,截留率可以达到100％,过滤阻力低于类似条件下的其他膜材料,在长时间运行后仍能保持较高的通量,表现出良好的抗污染性能.在过滤活性污泥时,截留率达到99.8％,单位压力下过滤通量达到1 170 L/(m·h·MPa).和其他膜材料相比,单位压力下的过滤通量表现出明显的优势.     

改性火山岩滤料去除矿井水中铁锰离子影响因素研究

以改性火山岩滤料作为除铁除锰的滤料,通过对模拟矿井水的过滤试验,研究了滤速、pH值、滤层厚度及铁锰离子浓度对其除铁除锰效率的影响。结果表明：改性火山岩滤料能实现模拟矿井水中Mn²⁺的100%去除,效果明显优于未改性火山岩;最为合理的过滤滤速为7～8 m/h;除铁除锰的过程主要发生在滤层厚度为90 cm的上部滤层中;随着铁锰浓度的升高,改性火山岩滤料除铁的效率变化很小,除锰效率呈快速、线性降低;中性或偏碱性的环境有利于改性火山岩滤料充分发挥高效吸附去除能力。     

环境相对湿度对颗粒物过滤性能的影响

以吸湿性氯化钠(NaCl)颗粒和非吸湿性氧化铝(Al₂O₃)颗粒为实验对象,使用纤维材料过滤介质,引入纳米和微米两类颗粒物尺度,考察不同相对湿度(RH)环境下颗粒物过滤性能的变化规律及内在机理。结果表明：低湿度下(RH20%和50%)过滤吸湿性颗粒时,压降呈线性增长趋势,高湿度下(≥RH80%)会出现压降的急剧升高;非吸湿性颗粒受湿度变化的影响较小,但在饱和湿度下(RH100%)压降增长较为显著;滤料初始过滤效率对环境中相对湿度的变化不敏感,也不会受到颗粒吸湿性能差别的影响;在颗粒加载过程中,受滤料纤维表面颗粒物沉积的影响,过滤效率持续缓慢增长,但湿度超过颗粒潮解点后,对吸湿性颗粒的过滤效率出现一定程度下降,类似液体过滤机制;此外,环境湿度的变化对于纳米颗粒物过滤性能的影响远比微米颗粒更为显著。研究结果可为空气污染防治中颗粒物过滤技术的应用与改进提供参考。     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.