钱塘江沉积物对染料亮蓝的吸附作用及影响因素

以钱塘江沉积物为研究对象,以亮蓝作为染料污染物的代表,研究感潮河口沉积物对染料的吸附作用及相关影响因素.结果表明:(1)沉积物吸附亮蓝是一个快速吸附过程,在很短的振荡时间内就有较高的吸附率,振荡10 min吸附率即达49％.当亮蓝等染料污染物因突发事故或偷排、漏排等进入钱塘江后,染料分子能在很短时间内吸附在沉积物上,随沉积物的运动在钱塘江中迁移.(2)亮蓝在沉积物上的吸附主要以表面吸附作用为主,等温吸附线可用Langmuir吸附模型拟合.经计算,亮蓝在钱塘江沉积物上的饱和吸附量约为2 780 mg/kg.(3)含沙量、盐度等因素对钱塘江沉积物吸附亮蓝有显著影响.沉积物用量越大,亮蓝吸附率越高,但当20 mL亮蓝溶液中沉积物用量高于0.4g(即含沙量20 kg/m3)时,其吸附率基本保持不变；在低盐度范围内,等温吸附线区分度不大,当盐度上升到0.100 mol/L(以NaC1摩尔浓度表征盐度)时,吸附量出现显著增加.     

多环芳烃在淮河、黄河和卫河沉积物上的吸附及解吸行为研究

以淮河沉积物上多环芳烃的吸附研究为主线,以黄河、卫河沉积物为比对,研究菲和芘在3种河流沉积物上的吸附和解吸行为,重点考察吸附剂有机质组分、环境温度、吸附时间和共存物等因素对吸附的影响,找出可以用来预测这3条河流沉积物对多环芳烃吸附作用的模式。结果表明,菲和芘在3种河流沉积物上的吸附均呈非线性,可用Freundlich方程拟合,属放热反应、物理吸附。同一吸附质的有机碳归一化分配系数(Koc)数值相近,说明吸附剂有机质组分对吸附起主导作用;吸附能力随着吸附时间延长而增加,并与吸附质疏水性成正比;多环芳烃共存,有竞争吸附现象;辛醇/水分配系数可用来预测3种河流沉积物对多环芳烃的吸附作用;解吸存在滞后现象,吸附质疏水性强、吸附剂有机质含量高的体系,解吸滞后现象更加明显。     

海河沉积物对邻苯二甲酸二甲酯吸附行为研究

邻苯二甲酸二甲酯(DMP)是一种广泛使用的化工原料,也是一种环境内分泌干扰物.研究了海河沉积物和土壤对DMP的吸附解吸作用,以及颗粒物粒径、浓度和离子浓度对DMP在颗粒物上吸附的影响.研究发现DMP在土壤上的吸附符合Langmuir等温式,在海河沉积物上的吸附符合线性等温式,单位吸附量随着颗粒物浓度的增大而减小,离子浓度的增大而增大,粒径对DMP的吸附影响不明显.用DMP将海河沉积物污染并于室温老化1个月后进行解吸实验,被吸附DMP解吸速率前20 h较快,以后逐渐达到吸附平衡,解吸量较小.     

CTMAB／SDS改性沸石对水中痕量邻苯二甲酸酯吸附机制

以季铵盐阳离子表面活性剂CTMAB及阴离子表面活性剂SDS对粉末状天然沸石进行复合改性,制备得到了CTMAB／SDS改性沸石。对改性沸石及天然沸石进行红外吸收光谱及XRD衍射表征,并研究了PAEs在天然沸石和CT-MAB／SDS改性沸石上的吸附机制。结果表明,阴阳离子表面活性剂没有对层状结构的键型造成较大的影响;PAEs在天然沸石和CTMAB／SDS改性沸石上的吸附更符合表面吸附一分配作用复合模型;PAEs的表面吸附和分配作用对吸附作用的贡献主要受吸附剂中有机质含量及吸附物质大小、极性及溶解度的影响。     

生物碳和土壤性质对乙草胺吸附行为的影响

生物碳施加到土壤中可能会影响污染物的环境归趋,而吸附作用是其关键控制因素,为此,本研究考察了400、500和600℃下制备的玉米秸秆生物碳(分别记作CS400、CS500和CS600)和土壤性质对乙草胺吸附行为的影响.结果表明,生物碳和土壤对乙草胺的吸附等温线符合Freundlich模型(R2≥0.99).随着生物碳热解温度的升高(从CS400到CS600),生物碳吸附乙草胺的非线性指数n值减小且logKOC值增大,说明吸附非线性程度和吸附能力增强,这是因为生物碳炭化程度增强(H/C原子比减小),疏水性增强(O/C原子比减小)和比表面积增大而有利于对乙草胺的吸附,吸附机制以表面吸附为主(比如疏水作用、π-ρ EDA作用和孔填充作用).然而,土壤吸附乙草胺的n值(0.95)接近1.0,说明该吸附作用几乎是线性吸附,以分配作用机制为主.3种生物碳对乙草胺的吸附能力都高于土壤,特别是CS600对乙草胺的吸附能力(logKoc)比土壤及文献报道的土壤和沉积物高一个数量及以上,说明生物碳可能会有效保留土壤中的乙草胺而降低其迁移性.     

皂化菠萝皮渣对重金属Zn2+的吸附

采用五因子二次回归正交旋转组合设计的方法对影响皂化菠萝皮渣吸附Zn2+的因子进行优化,得出在时间为1h、加入量0.1g、pH =9、温度20℃、浓度120 mg/L时,皂化菠萝皮渣有最大去除率yMax=99.12％.对比实验表明,皂化菠萝皮渣对Zn2+的吸附在低浓度时优于活性炭,纤维素在吸附中起主要作用.扫描电镜下菠萝皮渣表面显示粗糙和多褶皱的物理吸附特征,红外光谱显示皂化菠萝皮渣中OH、C=O、C-O基团参与吸附作用.吸附等温线和吸附动力学模型显示皂化菠萝皮渣对Zn2的吸附符合Freundlich等温式和二级动力学模型.吸附Zn2+后的皂化菠萝皮渣经过解吸附可以重复使用.     

小麦秸秆生物碳质吸附剂对硝基苯的吸附性能

在炭化温度为300℃下,用小麦秸秆制备生物碳质吸附剂,研究生物碳质吸附剂对硝基苯废水的吸附性能.考察了pH值、温度、吸附时间和吸附剂投加量对吸附效果的影响,分析了吸附剂在水中对硝基苯的吸附机理.结果表明,在pH值为7,温度为25℃,吸附时间为8h,吸附剂投加量为3 g/L条件下,生物碳质吸附剂对硝基苯的去除率达到90％.等温吸附曲线符合Freundlich方程,最大吸附量约为92.37 mg/g.定量描述了分配作用与表面吸附对生物碳质总的吸附作用的贡献,炭化后的小麦秸秆非极性增强,使硝基苯与其的极性更为匹配,引起分配作用增大.     

珠江河口湿地沉积物吸附氨氮及影响因素研究

沉积物对氨氮的吸附作用在河口湿地生态系统中的氮素循环过程中起着重要作用。采用实验室模拟的方法对珠江河口红树林、芦苇和光滩区表层湿地沉积物吸附氨氮的行为及影响因素进行研究。结果表明:3个不同区域沉积物对氨氮的吸附量呈现明显差异;植物区(红树林、芦苇区)沉积物对氨氮的承载能力强于光滩区;随上覆水盐度的增加,沉积物由吸附氨氮逐渐转变为释放氨氮;短时间水体扰动的加剧有助于沉积物吸附氨氮;沉积物对氨氮的吸附量随上覆水氨氮浓度升高而增加,但吸附率却逐渐下降;有机质含量的减少会降低沉积物对氨氮的吸附能力。     

吸附剂浓度对Zn(Ⅱ)和Cd(Ⅱ)在高岭土上吸附的影响

研究了吸附剂浓度(Cs)对Zn(Ⅱ)和Cd(Ⅱ)在高岭土上吸附的影响。结果表明,随Cs增大,吸附等温线下降,呈现出明显的吸附剂浓度效应(Cs-effect)。采用经典Langmuir和Freundlich吸附等温式对吸附数据进行拟合表明,在给定Cs下,Zn(Ⅱ)和Cd(Ⅱ)的吸附等温线分别符合Langmuir和Freundlich等温式;但这2个等温式不能描述或预测Cseffect,模型参数与Cs有关,与模型理论预测相悖。为解释和描述固/液界面吸附中的Cs-effect,我们近期提出了表面组分活度(SCA)模型,并推导出了Langmuir-SCA和Freundlich-SCA等温式。采用SCA模型等温式对吸附数据进行拟合表明,Langmuir-SCA和Freundlich-SCA等温式可分别准确地描述Zn(Ⅱ)和Cd(Ⅱ)在高岭土上吸附的Cs-effect结果,证明SCA模型是合理的。     

有机粘土矿物对水中低浓度菲的吸附性能和机理

分别选用十六烷三甲基溴化铵(HDTMA-Br)、四甲基溴化铵(TMA-Br)、聚乙二醇(PEG)表面活性剂改性天然粘土矿物,研究其对水中低浓度多环芳烃类难降解有机物菲的吸附性能和机理,并讨论了有机粘土的用量对吸附菲的性能的影响,验证了有机粘土矿物吸附菲后的稳定性.3种有机粘土矿物对菲的吸附等温线均呈中凹型,表现为分配系数(Kp)逐渐增大,表明吸附是分配作用和溶剂化效应共同作用的结果.根据Kp及土样有机碳含量(foc)所得的经有机碳归一化的分配系数(Koc)基本为常数,远远高于天然土壤/沉积物的Koc.在相同实验条件下,3种有机粘土矿物中HDTMA改性粘土矿物对菲的吸附性能最强,PEG改性粘土矿物次之,TMA改性粘土矿物最差.     

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).     

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。     

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。     

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.     

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     

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.     

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.