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1.
TiO_2光催化氧化降解印染废水的研究   总被引:3,自引:0,他引:3  
锐钛矿型TiO2为光催化剂,采用高压汞灯为光源对实际印染废水进行了光催化降解的研究,主要探讨了TiO2用量、光照时间、光照强度、溶液初始pH值和H2O2加入浓度等因素对印染废水CODcr去除率和脱色率的影响,找出了最佳的反应条件。结果表明:TiO2光催化氧化对印染废水CODcr和色度具有显著的去除效果,最佳的处理条件为:300W光照,TiO2用量为8g/L,光照时间为120min,初始pH值为1,H2O2加入浓度为3.0mmol/L。  相似文献   

2.
焦化废水污染物浓度高、生化降解难,利用纳米TiO2粉体,以紫外光(UV)为光源,进行了光催化处理焦化废水的试验研究,考察了TiO2用量、紫外光强度、焦化废水初始pH对COD和NH+4-N去除的影响;探讨了O2、O3、H2O2和Fenton试剂4种氧化剂与光催化的协同作用机理,分析了对COD和NH+4-N去除效果的影响,得出了最佳试验条件.结果表明,氧化剂与光催化协同作用使COD和NH+4-N的降解去除率得到了显著提高.在本试验条件下各氧化剂强化光催化对COD和NH+4-N去除率排序如下:TiO2+UV+Fenton>TiO2+UV+O3>TiO2+UV+H2O2>TiO2+UV+O2>TiO2+UV.  相似文献   

3.
TiO2光催化剂处理再生造纸废水的研究   总被引:1,自引:0,他引:1  
以TiO2为催化剂,用光催化氧化法处理再生造纸废水.讨论了不同实验条件如焙烧温度、焙烧时间、催化剂用量、H2O2用量、光照时间及废水pH值等对废水COD去除率的影响.结果表明:在焙烧温度为500 ℃,焙烧时间2 h,pH=8.0,TiO2用量为2.0 g/L,H2O2量(体积分数)0.6 %,光照时间4 h的条件下,废水COD的去除率可达90 %.  相似文献   

4.
黄碧莹 《广东化工》2012,39(17):101-103
采用TiO2光催化氧化法处理染料废水,讨论TiO2投加量、废水初始pH和光照时间对废水的CODCr去除率和脱色率的影响。结果表明:各因素对CODCr去除率影响程度的顺序为TiO2投加量>pH>光照时间;最佳反应条件为TiO2投加量3 g/L,pH=6.00,光照时间60 min;在最佳条件下,废水的CODCr去除率达到63.75%,色度去除率达到89.9%。TiO2光催化氧化法对染料废水的有效处理具有可行性。  相似文献   

5.
超声波辅助TiO2光催化降解印染废水的研究   总被引:18,自引:1,他引:18  
探讨了超声波辅助TiO2提高光催化降解印染废水速度的原因,研究了超声波辅助,H2O2以及溶液初始pH值对TiO2光催化降解印染废水速率的影响;用均匀试验设计方法确定了降解印染废水的最佳条件:TiO2的投加量0.52g/L,溶液的初始pH值3.5,n(金红石型):n(锐钛型TiO2)=1:3,质量分数为30%的H2O2的投加量3mL/L。  相似文献   

6.
TiO02光催化剂处理再生造纸废水的研究   总被引:1,自引:0,他引:1  
以TiO2为催化剂,用光催化氧化法处理再生造纸废水。讨论了不同实验条件如焙烧温度、焙烧时间、催化剂用量、H2O2用量、光照时间及废水pH值等对废水COD去除率的影响。结果表明:在焙烧温度为500℃,焙烧时间2h,pH=8.0,TiO2用量为2.0g/L,H2O2量(体积分数)0.6%,光照时间4h的条件下,废水COD的去除率可达90%。  相似文献   

7.
以钛板负载TiO2光催化剂对水中的硝基苯的催化降解进行了研究,考察了催化反应时间、溶液的pH值等因素对光催化反应的影响.实验结果表明,在实验条件下,光催化降解硝基苯的最佳条件为pH=3,反应时间100 min.用H2O2 UV TiO2光催化反应体系处理低浓度的硝基苯样品效果更好一些.  相似文献   

8.
研究了以悬浮态TiO2为催化剂,在H2O2存在的条件下,对壬基酚聚氧乙烯醚的光催化降解反应。分别考察了pH值、TiO2和H2O2的加入量、壬基酚聚氧乙烯醚的初始浓度以及光照时间对降解反应的影响。结果表明:在pH值为5,H2O2质量浓度为30mg/L的条件下,对初始质量浓度为50mg/L的壬基酚聚氧乙烯醚溶液光照4h后降解率达46.32%。  相似文献   

9.
焦化废水中有机污染物的光催化处理   总被引:3,自引:2,他引:3  
采用TiO2与粉末活性炭复合光催化剂(TiO2/PAC)对焦化废水中多种有机污染物进行了光催化处理。研究表明,TiO2/PAC对焦化废水中多种有机污染物的光催化处理具有良好的协同效应。将TiO2进行稀土掺杂后,可提高RE-TiO2/PAC对焦化废水中有机物的吸附能力。进一步考察了复合催化剂浓度、废水初始pH值、有机物(COD)的初始浓度、气体流量对最佳光催化剂Nd-TiO2/PAC处理焦化废水的影响。对COD初始浓度为385 mg/L、初始pH值为9.82的焦化废水,在气体流量为0.093 L/(L·min)、催化剂浓度4.0 g/L的条件下,经Nd-TiO2/PAC光催化处理90 min后,废水中的COD去除率可达89 %。  相似文献   

10.
UV-Fenton试剂处理焦化废水的研究   总被引:10,自引:2,他引:8  
采用VU-Fenton试剂对实际焦化废水进行氧化处理,通过正交试验和单因素试验,探讨了H2O浓度、FeSO4浓度、反应时间及溶液pH对水样COD及挥发酚去除的影响;在综合考虑经济性和去除效果的前提下,提出反应的最佳条件:FeSO4为0.2 g·100mL-1、H2O2为0.59 g·100mL-1、反应时间75min、溶液pH为6;试验结果表明,焦化废水经过UV-Fenton氧化处理后,COD去除率能迭到86%以上,挥发酚基本能被完全去除.  相似文献   

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12.
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

13.
14.
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.  相似文献   

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17.
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.  相似文献   

18.
Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

19.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

20.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

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