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1.
探索了试验过程中SiO2 -3 离子团的加入对脉冲自动倒极电解法合成聚合氯化硅酸铝中Alb 含量的影响。通过试验确定了最佳摩尔比。在脉冲倒极周期和电解槽电流一定的情况下 ,当总铝AlT 与SiO2 -3 的摩尔比为 10∶1~ 2 0∶1时 ;在此合成条件下制备液中Alb 含量超过 80 % ;处理模拟水样最佳投药量为 :0 5~ 5mgAl2 O3 /L。在制备过程中 ,极化现象得到了极好的控制 ,电解槽电压和电流十分稳定  相似文献   

2.
探索了试验过程中SiO3^2-离子团的加入对脉冲自动倒极电解法合成聚合氯化硅酸铝中Alb含量的影响。通过试验确定了最佳摩尔比。在脉冲倒极周期和电解槽电流一定的情况下,当总铝Al,与SiO3^2-的摩尔比为10:1~20:1时;在此合成条件下制备液中Alb含量超过80%;处理模拟水样最佳投药量为:0.5~5mgAl2O3/L。在制备过程中,极化现象得到了极好的控制,电解槽电压和电流十分稳定。  相似文献   

3.
用慢速滴碱法合成聚合氯化铝的过程中加入酸改性的凹凸棒,制备了新型絮凝剂APAC。采用Al-Ferron逐时络合比色法和烧杯絮凝实验法分别研究了APAC复合絮凝剂中铝的形态分布和絮凝性能。结果表明,Ala随盐基度的升高而逐渐降低;Alb随盐基度的升高而升高;Alc则先随盐基度的升高而升高,达到最大值后,再随盐基度的升高而降低。在相同实验条件下,盐基度愈高,混凝效果愈好,Alb含量愈高,混凝效果并不一定愈好。因此,APAC的质量控制以及追求目标应当是尽量提高Alc的含量,而不是Alb的含量。  相似文献   

4.
针对电絮凝处理污水过程中极板易发生钝化影响电絮凝效果的问题,采用倒极方法消除了极板钝化,并通过SEM和EDS,定性、定量分析不同反应时间段极板的表面形态和元素含量的变化,研究了表面钝化层成分及含量随处理时间的变化趋势。结果表明:电絮凝处理压裂废水中Al阳极钝化层的主要成分是Al_2O_3,阴极钝化层的主要成分是CaCO_3;倒极后的阴极板表面Al_2O_3含量在20 h内由48.94%下降到18.73%,阳极板Al_2O_3含量由11.87%降低到9.28%,这表明倒极能有效消除Al_2O_3氧化膜对极板钝化的影响;对于Ca~(2+)含量较低的压裂废水,倒极使CaCO_3的吸附量控制在0.01%~0.34%,可有效控制极板钝化现象的发生。  相似文献   

5.
应用曼尼希反应将植物单宁固定在苯乙烯-二乙烯苯共聚物上,制备一种新型固化单宁大孔吸附树脂.系统研究了胺基树脂的合成及其与单宁固化的工艺合成试验,得出最佳工艺条件为:胺基树脂:甲醛:单宁(质量比)=2:0.74:1,反应温度99~100℃,反应时间7 h.制备的固化单宁大孔吸附树脂具有较好亲水性,对水溶液中苯酚的吸附容量可达90 mg/g.该树脂易洗脱再生,重复使用效果好,对实际含酚废水的富集回收均获得了令人满意的结果.  相似文献   

6.
以硅酸钠、三氯化铁两种常用的无机原料合成聚硅氯化铁混凝剂(PFSC),试验其对微污染水的处理效果,并对其混凝机理作了初步的探讨。试验结果表明:r(Fe)/r(SiO2)摩尔比、pH值及投加量都会影响PFSC的混凝效果,其中以r(Fe)/r(SiO2)最为明显,当两者摩尔比为1.2时,所制备的PFSC混凝效果最佳,处理效率高于常规混凝剂。  相似文献   

7.
以硝酸溶解废碱性锌锰电池所得溶液为原料,采用溶胶-凝胶法成功地制备出了Mn0.6Zn0.4Fe2O4/SiO2磁性纳米复合材料, 并对制备机理进行了探讨.借助于DTA、TG、XRD、IR、SEM和TEM等手段对制备过程进行检测, 并对产物进行表征.研究表明,先将干凝胶在590 ℃条件下预烧,再在1 120 ℃条件下煅烧可直接合成粒径在20 nm左右具有尖晶石结构的磁性纳米复合材料.  相似文献   

8.
将脉冲电源和直流电源分别作为电凝聚处理废水的外加电源,拟试验探明电源对电凝聚处理废水的电能消耗的影响和相关参数的优化.试验结果表明,脉冲电源相对直流电源能更加有效降低阳极的超电位,减缓电极的极化,从而降低槽电压,进而有效地降低电能消耗.在试验条件下,脉冲频率对处理效果影响不显著,而脉冲占空比对处理效果有明显的影响,较合适的脉冲电源电凝聚处理废水的优化参数是:脉冲频率1 000 Hz、占空比60%.同时,对电解槽沉积絮凝物的处理进行了说明.  相似文献   

9.
采用Ferron逐时络合比色法对混凝体系中铝盐水解产物分布进行研究发现,铝盐在混凝体系发生水解反应获得的产物中Alb形态含量明显高于纯净水系,并且碱化度越低的铝盐,在适宜pH的混凝体系其水懈产物中Alb形态含量上升越快.而Alc形态含量变化不明显.提出混凝体系中铝盐水解反应的作用机制,指出HCO3-对H+浓度的良好控制是保证铝盐水解反应效率、获取高浓度Alb形态的关键.  相似文献   

10.
以大孔径SiO2为载体,通过钛酸丁酯溶液的浸渍、原位水解以及高温煅烧制备出大尺寸、大孔径的TiO2/SiO2光催化剂。利用自制空气净化装置对室内甲醛的清除进行研究,分别考察了TiO2的百分含量、紫外光光强、温度、湿度和空气流量等不同条件下TiO2/SiO2光催化剂对除去甲醛效率的影响。结果表明,反应温度从10~50℃依次升高,去除率逐渐下降。在相对湿度为50%,TiO2负载率为55.6%,流量为8 m3/h时,甲醛的最佳除去率达96.5%;经过7周时间的考察,发现TiO2/SiO2光催化剂的催化活性没有明显的下降。  相似文献   

11.
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  相似文献   

12.
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).  相似文献   

13.
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  相似文献   

14.
在实施ISO/IEC 17025:1999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,识别出内部审核策划阶段的关键环节,提出审核范围确定、审核计划和抽样方案制订的质量控制要求,为有序高效地实施内部审核提供了技术方法。  相似文献   

15.
16.
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.  相似文献   

17.
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。  相似文献   

18.

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 (ActivTM and BioCleanTM) 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.  相似文献   

19.
Bhattacharya A  Sarkar SK 《Ambio》2003,32(1):70-75
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.  相似文献   

20.
张仁泉 《污染防治技术》2005,18(2):15-17,34
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。  相似文献   

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