高强紫外光强化降解消毒副产物氯乙酸的效能及作用机制

氯乙酸是一种化学性质稳定的氯化消毒副产物,传统高级氧化技术对氯乙酸的降解效率低、矿化不彻底,拟采用强度高达3.13×10-6 Einstein/(cm2·s)(强度约合1000 mW/cm2,比传统高级氧化工艺中使用的紫外光强度高两个数量级以上)的紫外光作为光源,考察其对3种氯乙酸(一氯乙酸、二氯乙酸和三氯乙酸)的降解效果、影响因素和矿化过程.研究结果表明,与传统紫外光降解技术相比,高强紫外光可高效降解氯乙酸,前者在360 min内对氯乙酸的去除率不足5％,后者可在50 min内实现99％以上的降解,且3者的降解速率关系为:三氯乙酸>二氯乙酸>一氯乙酸.高强紫外光对氯乙酸的降解过程遵循伪一级动力学,光强、pH和DO这3个光解反应影响因素中,pH对氯乙酸光解过程影响不大,但光强和DO对光解速率影响显著,光解的反应速率随紫外光子通量的提高呈一次线性增加,随着DO由1 mg/L增加至9 mg/L,光解速率提高1倍.此外,高强紫外光对氯乙酸的矿化过程彻底,几乎不产生中间产物,氯乙酸的矿化过程可能主要是通过脱卤和脱羧基两个反应路径实现,DO和pH对光解过程的影响从侧面佐证了氯乙酸高强紫外光光解路径.该结果表明,高强紫外光可有效降解光稳定物质氯乙酸,可为氯化消毒副产物的高效去除提供技术借鉴.     

酞酸二丁酯在铁(Ⅲ)-草酸盐配合物体系中的光降解

在铁(Ⅲ)-草酸盐配合物体系中考察pH值,铁(Ⅲ)／草酸盐(Fe(Ⅲ)／Ox)配比,酞酸二丁酯(DBP)初始浓度对DBP光降解的影响,结果表明pH=3．5和Fe(Ⅲ)／Ox配比为10．0／120．0μmol／L时具有较强的氧化能力,其光解反应符合表观一级反应动力学规律。并且利用气相色谱-质谱联机分析确定DBP光降解得中间产物,揭示DBP光降解的主要反应途径是OH自由基提取烷基上与羧基相连的α-H,生成醇(ROH),再分解成为酞酸和二醇,进一步氧化脱羧,直至矿化。     

天然水源水中DBP紫外降解效果和机理研究

研究了254 nm紫外光照射条件下邻苯二甲酸二丁酯(DBP)的降解效果和机理。结果表明,紫外强度和初始浓度通过改变单位浓度DBP所获得的光子能量影响降解效果,溶液pH对降解效果没有显著影响。单纯紫外照射对DBP去除效果相对较差,在低浓度条件下较为适用,这主要是因为DBP降解主要依靠其自身直接光解,在初始浓度10 mg/L左右,紫外强度0.62 W/L条件下,紫外照射6 h的降解效率最高能达85%。低腐殖酸条件下,DBP紫外降解符合一级反应动力学,添加腐殖酸条件下的反应速率变小,说明腐殖酸对DBP的吸附作用较其作为光敏物质增加降解效率的能力强。机理研究表明,DBP降解主要从侧链开始,进一步降解为苯甲酸等中间体,最后降解为二氧化碳和水。     

天然水源水中DBP紫外降解效果和机理研究

研究了254 nm紫外光照射条件下邻苯二甲酸二丁酯(DBP)的降解效果和机理。结果表明,紫外强度和初始浓度通过改变单位浓度DBP所获得的光子能量影响降解效果,溶液pH对降解效果没有显著影响。单纯紫外照射对DBP去除效果相对较差,在低浓度条件下较为适用,这主要是因为DBP降解主要依靠其自身直接光解,在初始浓度10 mg/L左右,紫外强度0.62 W/L条件下,紫外照射6 h的降解效率最高能达85%。低腐殖酸条件下,DBP紫外降解符合一级反应动力学,添加腐殖酸条件下的反应速率变小,说明腐殖酸对DBP的吸附作用较其作为光敏物质增加降解效率的能力强。机理研究表明,DBP降解主要从侧链开始,进一步降解为苯甲酸等中间体,最后降解为二氧化碳和水。     

Cu2O光催化降解水中环境内分泌干扰物己烯雌酚性能的研究

采用水解法制备Cu2O,以Cu2O为催化剂,对光催化降解环境内分泌干扰物己烯雌酚(DES)的性能和影响因素进行了研究,利用高效液相色谱法(HPLC)测定降解后水中DES的含量.探讨了溶液的初始浓度、催化剂投加量、pH值以及光照时间对降解效率的影响.当DES初始浓度为51μg/mL,催化剂投加量为0.8g/L,pH值=4.0,光照120min的条件下降解效果达95.02%.     

紫外光降解水中痕量NDMA的效能研究

采用紫外光降解水中痕量亚硝基二甲胺（NDMA）,研究了NDMA初始浓度、溶液pH值、光照面积、紫外光辐射强度以及水质对紫外光降解NDMA的影响。络果表明,紫外光能够有效降解水中的NDMA,紫外光解反应5min,NDMA去除率可以达到97．5％。初始浓度对NDMA的光降解去除率影响不大。     

UV/PS去除饮用水中亚硝基二丙胺的研究

采用紫外/过硫酸盐(UV/PS)高级氧化技术去除饮用水中含氮消毒副产物亚硝基二丙胺(NDPA),考察了PS投加量、NDPA初始浓度、pH值、共存阴离子对NDPA降解效率的影响,并拟合其动力学模型。结果表明,单独UV辐射以及单独PS氧化,去除效果均不显著;UV/PS联用有较高的降解效果,在反应温度为25℃、pH值为7.0、紫外光照强度为168μW/cm²下,最佳PS投加量和NDPA初始浓度分别为0.05 mmol/L和200μg/L时,UV/PS可在40 min内降解75%以上的NDPA。NDPA的降解速率随着PS投加量的增大而增大,随着NDPA初始浓度的增加而降低;随着pH值的增大而减小;共存阴离子NO2下,最佳PS投加量和NDPA初始浓度分别为0.05 mmol/L和200μg/L时,UV/PS可在40 min内降解75%以上的NDPA。NDPA的降解速率随着PS投加量的增大而增大,随着NDPA初始浓度的增加而降低;随着pH值的增大而减小;共存阴离子NO^-_3对NDPA的去除具有轻微的抑制作用,而HCO-_3对NDPA的去除具有轻微的抑制作用,而HCO^-_3、Cl-_3、Cl^-对NDPA的去除具有一定的促进作用。其降解均符合一级动力学。     

UV/Fenton/草酸体系对甲基紫的光解脱色作用

以草酸为活化剂在室温和紫外光照射下,,进行了Fenton反应光解甲基紫的试验。结果表明UV对甲基紫光降解反应的速率起决定性作用,H2O2浓度和Fe2+浓度是影响降解速率的主导因素,草酸在反应过程中起到了活化剂的作用。在甲基紫浓度为20 mg/L时,其脱色的适宜条件为3%H2O2、100 mg/L Fe2+、100.6 mg/L草酸、体系pH值约为3。     

天然黑钨矿应用于光催化降解土霉素

采用天然半导体矿物黑钨矿作为光催化剂用于降解废水中的土霉素。研究了固液比、光照强度、初始浓度对土霉素降解的影响，并解析了降解机理和路径。结果表明，可见光下黑钨矿对土霉素具有较好的降解效果，在浓度为15 mg/L、pH=4.5、固液比为1.0 g/L、光照强度60 W的条件下，120 min时土霉素的去除效率可以达到94.3%，黑钨矿对于土霉素的去除速率符合一级动力学反应规律。淬灭实验和电子顺磁光谱结果表明羟基自由基(·OH)和超氧阴离子自由基(·O₂^-)是导致土霉素降解的主要活性氧化物种，分别在120 min时降解了20.4%和10%的土霉素。液相色谱-质谱联用显示土霉素经过羟基化、去甲基化、和脱羰化降解为中间产物，使其化学毒性下降，有利于工艺在抗生素处理中的工业化应用。     

H_2O_2辅助氧化石墨烯光降解罗丹明B

采用传统Hummer法制备氧化石墨烯(GO),以罗丹明B作为目标污染物,研究GO的光降解性能。研究结果表明,GO表现出优异的光降解罗丹明B性能,在GO投加质量浓度为0.15 g/L,罗丹明B质量浓度为10 mg/L(200 m L),300 W氙灯光照120 min后,对其降解率达到86.99%;加入1.0 m L H_2O_2,120 min后光降解率可达到96.14%;羟基自由基捕获实验证明H_2O_2/GO光催化罗丹明B主要遵循羟基自由基氧化机制。在GO投加质量浓度为0.15 g/L,H_2O_2用量为2.0 m L,罗丹明B质量浓度10 mg/L,pH为3,光照10 min降解率达到98%。     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。