黄铁矿活化不同类型氧化剂降解活性红X-3B效能比较

以活性红X-3B为目标污染物，探究黄铁矿活化H₂O₂、KHSO₅、Na₂S₂O₈、CaO₂和KMnO₄等5种氧化剂处理模拟染色废水效能，研究了氧化剂投加量、反应时间及黄铁矿重复利用对含活性红X-3B模拟染色废水脱色率、COD去除率和TOC去除率的影响；测定了反应体系中铁离子浓度和pH变化，并通过自由基淬灭实验与电子顺磁共振实验研究产生的活性物种。结果表明，在黄铁矿活化作用下，5种氧化剂对活性红X-3B的脱色率均能达到95%以上，而黄铁矿二次回用时，KMnO₄、CaO₂和Na₂S₂O₈对活性红X-3B氧化去除效果不佳；但以H₂O₂和KHSO₅为氧化剂，黄铁矿重复利用十次，活性红X-3B脱色率均大于99%,COD去除率为42.45%和30.88...     

两级芬顿处理垃圾渗滤液工艺研究

根据广西横州某垃圾填埋场渗滤液COD浓度高、水质成分复杂，且处理难度较大的特点，设计采用新型两级芬顿氧化工艺对其进行处理。研究对比了两级芬顿与絮凝-芬顿联合处理工艺对该渗滤液中COD的去除效果，通过试验研究了pH值、FeSO₄用量、H₂O₂用量三个因素对处理效果的影响，并确定最佳反应条件。结果表明，两级芬顿氧化工艺对垃圾填埋场渗滤液COD的去除效果更好，在反应条件pH为4.5,FeSO₄投加量10 g/L、H₂O₂投加量0.55 g/L时，COD去除率可达到90%以上。     

印染化工废水光催化氧化深度处理试验

芬顿氧化法因其具有较好的有机物降解效果已应用于许多大规模的污水深度处理工程中,近年来发展出以紫外光(UV)/H₂O₂等方法为代表的类芬顿技术,其基本原理与使用方法均与芬顿技术类似,但光芬顿所需的Fe²⁺浓度更低,反应不需要很低的pH,运行更加高效、安全和简单。文章通过构建光芬顿反应体系,搭建光芬顿反应装置,以H₂O₂投加量、亚铁盐投加量、反应pH、光源为反应条件参数,以COD_&去除效果为降解性能指标,优化降解反应过程中的工艺参数,验证了光芬顿体系对废水COD_Cr的去除机理,确定了光芬顿体系的最优反应条件,并研究了降解规律,分析了经济成本,提出了光芬顿体系对印染化工废水深度处理的应用建议。试验中最优反应条件如下:pH值为6,H₂O₂投加量为400 mg/L,Fe²⁺投加量为21.0 mg/L。该条件下,经过光芬顿处理,可将二沉池出水的COD_&     

宽pH条件下Mn3O4/ACF复合阴极类电芬顿体系降解亚甲基蓝

用电化学方法将Mn₃O₄负载于活性炭纤维（activated carbon fiber,ACF）表面制备了Mn₃O₄/ACF复合阴极,与铂丝阳极构成了异相类电芬顿体系对模型污染物亚甲基蓝（MB）进行降解,考察了该体系在不同pH条件下对MB去除率,并对体系中的活性氧物种进行了检测,初步探讨了降解机理。实验结果表明,在pH 3.0、pH 5.0和pH 7.0时亚甲基蓝脱色率分别达到97.3%、99.9%、99.8%,pH5.0时TOC去除率达到88.6%,pH 7.0和pH 3.0时也分别达到了80.4%和73.4%,拓宽了电芬顿反应的适宜pH范围。体系中活性氧物种的检测结果表明,氧在阴极电还原产生H₂O₂,并与Mn₃O₄反应生成羟基自由基·OH,同时,氧的一电子还原产物超氧自由基O₂·^-也对阴极表面污染物的脱色有重要贡献。     

Fe0类Fenton氧化处理农药中间体废水

通过单因素实验探究了Fe⁰类Fenton氧化处理农药中间体废水过程中的最适Fe⁰和H₂O₂投加量、初始pH值和最佳处理时间，研究了处理后出水BOD₅/COD_Cr(B/C)值、体系中亚铁和总铁含量以及·OH的变化规律。结果表明Fe⁰类Fenton体系中，最适Fe⁰投加量为6.59 g/L,H₂O₂投加量为3.33 g/L,初始pH=3,处理时间为50 min, COD_Cr去除率达到42.50%。相比于传统Fenton体系，Fe⁰类Fenton体系COD_Cr 去除率提高了约17%,出水B/C值达到0.34,加速了·OH的产生，H₂O₂添加量明显减少，铁的利用效率得到提高，可以有效减少含铁污泥的生成。     

内循环式铁碳微电解/H2O2耦合工艺处理多晶硅有机废水

针对铁碳微电解反应中填料易板结及处理效率低等问题,通过增加内循环装置改进反应器结构,同时将铁碳微电解与H₂O₂进行工艺耦合,用于处理多晶硅有机废水,考察了Fe-C投加量、初始pH值、H₂O₂投加量、反应时间等工艺条件对COD去除率的影响,并通过响应面法优化了工艺条件。结果表明,各工艺条件对多晶硅有机废水COD去除效果的影响大小为：铁碳投加量>反应时间>H₂O₂投加量>初始pH值,其最适宜工艺条件为：铁碳投加量250 g·L^-1,初始pH值2.8,H₂O₂投加量112 mL·L^-1,反应时间83 min,该反应条件下COD的去除率为71.26%。铁碳/H₂O₂降解多晶硅有机废水COD的动力学回归方程为Y=0.5273X-0.6347,降解COD的速率常数为0.527 3 min^-1。     

改性活性碳纤维电芬顿降解活性艳红X-3B

以石墨为阳极,改性活性炭纤维(ACF)为阴极,采用电芬顿法降解活性艳红X-3B染料废水模拟废水。研究了Fe~(2+)浓度、p H值、电流密度对染料脱色率的影响,结果表明:阴极电芬顿法对活性艳红X-3B染料废水具有有较高的去除率,在最佳反应条件Fe2+投加量为1mmol/L,pH值为3.0,电流密度为7.5m A/cm~2,反应时间为60min时,染料的脱色率可以达到97.6%。     

两级芬顿对膜滤浓缩液与垃圾渗滤液协同处理的工艺研究

由于南宁市某产业园生活垃圾填埋场的膜滤浓缩液停止回灌，南宁市城南生活垃圾卫生填埋场渗滤液处理站需承担部分膜滤浓缩液的处理任务。本研究将膜滤浓缩液与垃圾渗滤进行混合，使用两级芬顿和絮凝芬顿联合法对膜滤浓缩液与垃圾渗滤液进行协同处理，对比这两种工艺对混合液中的COD去除效果。结果表明，两级芬顿氧化法对混合液中的COD的去除效率更高，最佳反应条件为pH值为4.0,FeSO₄投加量为12 g/L、H₂O₂投加量为25 mL/L时，COD去除率为92.24%以上。     

电芬顿工艺对垃圾渗滤液纳滤浓缩液的处理性能研究

本研究采用电芬顿工艺处理垃圾渗滤液纳滤浓缩液,系统考察电流密度、n(H₂O₂):n(Fe²⁺)、pH等工艺参数对渗滤液纳滤浓缩液COD的去除性能,运用响应曲面法推算最优工艺条件。结果表明,电芬顿处理渗滤液纳滤浓缩液的最优工艺参数反应时间为2h,电流密度为6.471 mA/cm²,n(H₂O₂):n(Fe²⁺)为12,pH为3.78,COD去除率可达到80.7%。     

Cu2+和Co2+促进芬顿氧化处理垃圾渗滤液的研究

通过在传统芬顿体系中加入Cu²⁺、Co²⁺,研究Cu²⁺/Co²⁺/Fe²⁺/H₂O₂、Cu²⁺/Fe²⁺/H₂O₂、Co²⁺/Fe²⁺/H₂O₂和Fe²⁺/H₂O₂四种芬顿体系对垃圾渗滤液的处理效果,发现当初始pH分别为2、3、4、5、6时,各体系去除CODCr的效果排序为Cu²⁺/Co²⁺/Fe²⁺/H₂O₂>Cu²⁺/Fe²⁺/H₂O₂>Co²⁺/Fe^2...     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.