累托石/腐殖酸微球的制备及其对Cr(Ⅵ)的吸附研究

采用累托石（REC）、腐殖酸（HA）等材料制备微球状吸附剂,考察了累托石、腐殖酸、聚乙烯醇（PVA）、海藻酸钠（SA）、氯化钙等材料的用量对制得的微球吸附性能的影响,通过正交试验确定了微球的最佳制备条件,还考察了微球用量、振荡时间和溶液pH值等因素对微球吸附去除水中Cr(VI)效果的影响。结果表明,采用累托石、腐殖酸、聚乙烯醇等材料可制得高效去除水中六价铬离子的微球状吸附剂,微球的最佳制备条件为：REC 1%,HA 4%,PVA 7%,SA 0.1%,CaCl₂ 0.5%。制得的累托石/腐殖酸微球孔系发达,吸附性能良好。在温度30℃,微球用量0.02 g/mL,振荡时间为2.5 h,pH值为1的条件下,微球对Cr(VI)的吸附效率可达98%以上。     

蜣螂壳聚糖对铀的吸附研究

制备了蜣螂脱色壳聚糖和蜣螂未脱色壳聚糖,研究了时间、pH及铀初始浓度对其吸附铀的影响,探讨了吸附等温线和吸附动力学规律,并与虾壳聚糖进行对比。结果表明:蜣螂未脱色壳聚糖对铀的吸附率高于蜣螂脱色壳聚糖和虾壳聚糖;最佳吸附条件为铀初始质量浓度50mg/L、时间3.0h、pH=4.0,其中铀初始浓度的影响最显著;蜣螂未脱色壳聚糖对铀吸附过程符合Langmuir、Freundlich吸附等温方程和准二级吸附动力学方程。     

季铵化改性木屑纤维素的制备及对氟离子的吸附研究

以3-氯-2-羟丙基三甲基氯化铵(CTA)为醚化剂,对木屑纤维素进行了季铵化改性.探讨了季铵化改性木屑纤维素用量、pH、吸附温度、氟离子初始浓度和吸附时间对氟离子静态吸附率的影响,以及流速对氟离子动态吸附率的影响.结果表明:(1)静态吸附最佳工艺条件:季铵化改性木屑纤维素用量为3.0 g/L,pH为4.0～6.0,吸附温度为25 ℃,吸附时间为120 min.在此最佳工艺条件下,季铵化改性木屑纤维素对100 mL 50.00 mg/L氟离子溶液的吸附率最高可达90.11%.(2)在pH为5.0、25 ℃的条件下,将50.00 mg/L氟离子溶液以5 mL/min的流速流经装有3.0 g/L季铵化改性木屑纤维素的吸附柱,吸附率可达97.95%.(3)季铵化改性木屑纤维素对溶液中氟离子的吸附过程为放热过程,在吸附过程中存在着化学吸附.(4)木屑来源丰富、价格价廉,季铵化改性木屑纤维素对溶液中氟离子的吸附效果好,且吸附工艺简单、易于实现工业化,具有良好的应用前景.     

改性壳聚糖处理污水中Ni(Ⅱ)的效果

通过丁二酸酐与γ-氨丙基三甲氧基硅烷改性后的纳米SiO2(即可分散的纳米二氧化硅,简称DNS)反应,合成了羧基化的DNS,再经过与壳聚糖脱水生成酰胺的过程,合成了改性壳聚糖。通过红外光谱和扫描电镜对改性壳聚糖进行表征。研究了壳聚糖及改性壳聚糖微粒吸附Ni2+时溶液pH值、时间、吸附剂用量和Ni2+初始浓度等对吸附率的影响,并确定了最佳条件为:pH=7,吸附时间为120 min,吸附剂的投加量为0.3 g。改性壳聚糖比壳聚糖具有更强的吸附Ni2+的能力,吸附率达67.01%。     

聚乙烯醇-海藻酸钠固定铜绿微囊藻对磷的吸附

利用聚乙烯醇与海藻酸钠固定包埋铜绿微囊藻,通过正交实验获得聚乙烯醇溶液浓度、海藻酸钠溶液浓度及铜绿微囊藻液量去除磷的最佳配比,研究溶液起始pH值、反应时间、磷初始浓度对固定化小球吸附磷的影响。结果表明,固定化小球的最佳制备条件为聚乙烯醇质量分数6%,海藻酸钠质量分数0.5%及铜绿微囊藻浓度2×107个/mL;固定化小球吸附磷的最适起始pH值为6～8,吸附达到平衡的时间为9～12 d,初始磷浓度为1.00 mg/L时去除率最高,达到79.19%。     

硝酸改性稻秆处理含Pb~(2+)模拟废水

在150 m L溶液中,稻秆用量为5 g,硝酸浓度为10%,稻秆颗粒度为20目,改性温度为80℃,改性时间为3h,制备得到硝酸改性稻秆吸附剂。详细探讨了用该吸附剂处理含Pb~(2+)废水的影响因素:吸附剂用量、Pb~(2+)初始浓度、溶液pH值、吸附时间和吸附温度等对Pb~(2+)吸附率的影响,并进一步通过正交实验及对比实验得出处理200 m L,初始浓度为300mg·L-1的含Pb~(2+)废水的最佳吸附工艺为:吸附剂用量为4 g,pH值为6,吸附时间为3 h,吸附温度为20℃,在此工艺条件下,对Pb~(2+)的吸附率达到94.31%,吸附量为14.15 mg·g~(-1)。     

改性玉米芯吸附溶液中的铀

以KMnO4改性玉米芯为吸附剂来吸附溶液中的铀,并与未改性玉米芯的吸附能力进行比较。考察了玉米芯用量、溶液pH值、铀初始质量浓度以及吸附时间等因素对铀吸附效果的影响。实验结果表明,当溶液pH=5.5、改性玉米芯用量为0.12 g、未改性玉米芯用量为0.2 g、铀初始质量浓度为30 mg/L、接触时间为2.5 h时,改性玉米芯对铀的去除率为93.54%,未改性玉米芯对铀的去除率为59.68%,改性玉米芯对铀的吸附效果明显优于未改性玉米芯。     

核桃壳对模拟废水中Cu~(2+)的吸附性能研究

采用核桃壳作为吸附剂,对模拟废水中的Cu2+进行吸附去除,考察了吸附剂粒径、水样初始pH、吸附剂用量、Cu2+初始浓度、吸附时间等因素对Cu2+吸附效果的影响,确定最佳吸附参数,并进行了吸附动力学和吸附等温线分析。结果表明:最佳吸附参数为核桃壳吸附剂粒径1.25~1.60mm、水样初始pH 5.0、吸附剂用量2.5g,Cu2+初始质量浓度20mg/L、吸附时间360min,在此条件下100mL水样在200r/min、25℃条件下吸附的Cu2+去除率达70%以上,吸附量约为0.702mg/g;本实验过程采用伪二级动力学方程的拟合更好,R2均在0.9以上,Cu2+吸附速率与其浓度的二次方成正比;Langmuir方程可以较好地描述核桃壳吸附剂对Cu2+的吸附过程,此吸附过程是单分子层的吸附。     

米糠生物质解毒含铬(Ⅵ)水溶液的研究

农林生物质是一种成本低、环境友好的重金属废水处理材料,也是受重金属污染环境的修复材料之一.实验讨论了初始pH值、米糠用量、吸附时间对含铬(Ⅵ)水溶液解毒的影响.结果表明,米糠对Cr(Ⅵ)存在吸附作用,同时也有解毒还原能力.100 mL浓度为100 mg/L的含铬溶液,在初始pH为2、米糠用量为3 g、吸附-反应平衡时间7 h的条件下,生物质吸附去除溶液中的铬为14.4%,而原溶液中Cr(Ⅵ)解毒了57.2%,米糠生物质吸附总铬的能力为0.48 mg Cr/g(生物质).米糠生物质有潜在的吸附铬和修复受铬污染环境的利用价值.     

工业废渣基除磷材料的静态吸附研究

研究了高效除磷材料（EPRC）对磷素的吸附特性,考察了投加量、初始浓度、初始pH值、粒径等对EPRC吸附性能的影响,分析了不同条件下EPRC的吸附过程。结果表明,最佳投加量为3.5 g/250 mL时,去除率达91.07%,出水TP浓度为0.45 mg/L。随着粒径减小,EPRC对磷素的吸附量增大,吸附平衡时间缩短。溶液初始pH值在碱性条件下,吸附容量变大。     

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.