Effect of various sono-oxidation parameters on the removal of aqueous 2,4-dinitrophenol

The influences of ultrasonic output intensity, solution pH, H₂O₂ concentration and the addition of Fenton reagent on the degradation of 2,4-dinitrophenol (DNP) under ultrasonic irradiation were investigated. It was observed that the degradation of DNP fitted pseudo-first-order dynamics under our experimental conditions. Increasing the ultrasonic output intensity increased the degradation efficiency of DNP and low pH favored the ultrasonic degradation of DNP. The addition of H₂O₂ enhanced the ultrasonic degradation efficiency of DNP. The further addition of Cu²⁺, however, hindered the degradation of DNP. In contrast, sono-oxidation treatment in combination with FeSO₄/H₂O₂ showed a synergistic effect for DNP degradation.     

Radiation induced chemisorption of oxygen on chromia

The effect of nuclear radiation on the chemisorption of oxygen on Cr₂O₃, Cr₂O₃-Al₂O₃ and Cr₂O₃-SnO₂ catalysts has been studied. An iodometric method was used to measure the amount of chemisorbed oxygen; simultaneously the increase in the catalytic activity of the catalyst in the decomposition of H₂O₂ was determined. It was found that the radiation present within a nuclear reactor promotes the chemisorption of oxygen on chromia (either pure or supported on Al₂O₃ or SnO₂) at temperatures at which such a chemisorption does not normally occur. The radiochemisorption of oxygen on chromia increases with the degree of dispersion of chromia on Al₂O₃ or SnO₂ and is accompanied by an increased catalytic activity of this catalyst in the decomposition reaction of H₂O₂. It seems that the radiochemisorption is largely due to the action of γ-rays and fast neutrons on the gas.     

Fe3O4磁性纳米颗粒的催化性能研究进展

综述了国内外这一领域科研工作者的研究成果,以紫外光谱（UV）和电化学传感器为主要手段阐述了Fe₃O₄MNPs对H₂O₂的催化作用并对Fe₃O₄MNPs利用其催化性质在H₂O₂的检测领域的进一步发展和应用进行了展望。     

Kinetics and mechanisms of ultrasonic degradation of volatile chlorinated aromatics in aqueous solutions

Ultrasonic decompositions of chlorobenzene (ClBz), 1,4-dichlorobenzene and 1-chloronaphthalene were investigated at 500 kHz in order to gain insight into the kinetics and mechanisms of the decomposition process. The disappearance of ClBz on sonication is almost simultaneously accompanied by the release of chloride ions as a result of the rapid cleavage of carbon–chlorine bonds with a concomitant release of CO, C₂H₂, CH₄ and CO₂. The intermediates resulting from attack of HO^√ radicals were detected but in a quite low yield (less than 2 μM). The generation of H₂O₂ on sonolysis is not significantly affected by the presence of aqueous ClBz while the generation of NO₂⁻ and NO₃⁻ is inhibited initially due to the presence of ClBz which diffuses into the gas–bubble interfaces and inhibits the interactions between free radicals and nitrogen. Moreover, brown carbonaceous particles are present throughout the ultrasonic irradiation process, which are consistent with soot formation under pyrolytic conditions. These important features suggest that, at the relatively high initial substrate concentrations used in this study, ultrasonic degradation of ClBz takes place predominantly both within the bubbles and within the liquid–gas interfaces of bubbles where it undergoes high-temperature combustion. Under these conditions, the oxidation of ClBz by free radical HO^√ outside of bubbles is a minor factor (though results of recent studies suggest that attack by HO^√ is more important at lower initial substrate concentrations). The sonochemical decomposition of volatiles follows pseudo-first-order reaction kinetics but the degradation rates are affected by operating conditions, particularly initial substrate concentration and ultrasonic intensity.     

氧化反应调控的金纳米簇“关-开”型荧光探针检测过氧化氢和葡萄糖

基于过氧化氢（H₂O₂）氧化单巯基（—S）为双巯基（S—S）,抑制金纳米簇（AuNCs）荧光猝灭,建立了一种灵敏的荧光传感方法用于过氧化氢和葡萄糖（Glu）的检测。DNA为模板合成的金纳米簇作为荧光探针,荧光强度高、稳定且合成简单快速。加入半胱氨酸（Cys）,半胱氨酸上的单巯基可以与金纳米簇发生化学键合反应形成稳定的Au—S键,破坏金纳米簇的结构,导致金纳米簇荧光强度猝灭。但当体系中存在过氧化氢时,将单巯基半胱氨酸氧化成双巯基的胱氨酸。双巯基的胱氨酸不能与金纳米簇发生键合作用,金纳米簇在471 nm处发射出强烈的荧光信号。葡萄糖可以在葡萄糖氧化酶（Gox）的作用下产生过氧化氢,利用该方法进一步开展了对葡萄糖的检测。以金纳米簇荧光强度的变化值F/F₀为纵坐标,过氧化氢或葡萄糖浓度为横坐标,实现了对过氧化氢和葡萄糖的灵敏检测,线性范围分别为10~100和10~200 μmol·L-1,检测下限分别为2.8和3.1 μmol·L-1。选择4种其他糖类化合物和5种金属离子作为干扰物质,均不会抑制半胱氨酸对金纳米簇的荧光猝灭效应,表明该方法具有很好的选择性。用该方法成功检测了胎牛血清样品中的葡萄糖,加标回收率为94.5%~112.7%。此外,该方法可拓展到其他基于酶催化产生过氧化氢体系的分析物检测,如胆固醇、辣根过氧化物酶等,为过氧化氢相关反应的分析提供了一种通用、简便的方法,在临床诊断、食品科学和环境分析等领域具有潜在的应用价值。     

Decolorizing of azo dye Reactive red 24 aqueous solution using exfoliated graphite and H2O2 under ultrasound irradiation

At its natural pH (6.95), the decolorization of Reactive red 24 in ultrasound, ultrasound/H₂O₂, exfoliated graphite, ultrasound/exfoliated graphite, exfoliated graphite/H₂O₂ and ultrasound/exfoliated graphite/H₂O₂ systems were compared. An enhancement was observed for the decolorization in ultrasound/exfoliated graphite/H₂O₂ system. The effect of solution pH, H₂O₂ and exfoliated graphite dosages, and temperature on the decolorization of Reactive red 24 was investigated. The sonochemical treatment in combination with exfoliated graphite/H₂O₂ showed a synergistic effect for the decolorization of Reactive red 24. The results indicated that under proper conditions, there was a possibility to remove Reactive red 24 very efficient from aqueous solution.

The decolorization of other azo dyes (Reactive red 2, Methyl orange, Acid red 1, Acid red 73, Acid red 249, Acid orange 7, Acid blue 113, Acid brown 75, Acid green 20, Acid yellow 42, Acid mordant brown 33, Acid mordant yellow 10 and Direct green 1) was also investigated, at their natural pH.     

草酸沉淀法制备细颗粒红色荧光粉Y2O3：Eu3+的发光特性

对草酸作为沉淀剂制备的细颗粒红色荧光粉Y₂O₃:Eu³⁺进行结构和发光特性研究,结果表明:其一次粒径为20～30nm,团聚尺寸D₅₀=0.53μm。该荧光粉最大激发峰位于252.2nm,较微米级荧光粉233nm红移了19.2nm;最大的发射峰位于612nm,与微米级的相比几乎没有差别。Eu³⁺离子的掺入构成了发光中心,其最佳掺杂的质量分数为9%,荧光粉发光的猝灭浓度由微米级的6%提高到9%。由于纳米晶存在表面缺陷和悬挂键,其亮度约为微米晶的70%左右,随着团聚尺寸的增加、煅烧温度的提高和助熔剂的加入,荧光粉的发光强度增大。包膜能部分消除表面缺陷和悬挂键,提高发光亮度。荧光粉的色坐标为x=0.6479,y=0.3442。     

基于光谱分析探讨磷酸与焦磷酸改性生物炭的磷素形态

通过磷酸（H₃PO₄）和焦磷酸（H₄P₂O₇）对生物炭改性能够使其更适于农业应用。探明H₃PO₄和H₄P₂O₇改性生物炭的P赋存形态与结合方式，将有助于揭示其表面P的生物有效性。以麦秆生物炭（WBC）与棉秆生物炭（CBC）为原料，分别通过H₃PO₄和H₄P₂O₇制备了H₃PO₄改性生物炭（P-WBC和P-CBC）和H₄P₂O₇改性生物炭（PA-WBC和PA-CBC）。利用拉曼光谱（Raman）与扫描电镜能谱（SEM-EDS）对改性生物炭结构与P分布变化进行表征，采用傅里叶红外光谱（FTIR）和X射线光电子能谱（XPS）探究改性生物炭表面P结合方式，并结合Hedley磷分级方法与可见分光光度法，定量分析改性前后生物炭中P形态及含量变化。结果表明，H₃PO₄和H₄P₂O₇改性后生物炭I_G/I_D值增大，石墨化结构增强，形成了含P颗粒状结构。H₃PO₄和H₄P₂O₇改性促进了生物炭表面羧基（—COOH）、P—O—P和P—H等酸性官能团与含P基团的形成，且H₃PO₄改性生物炭和H₄P₂O₇改性生物炭表面官能团种类相似。XPS结果显示，与WBC和CBC相比，改性处理中的O(1s)峰相对含量显著增加了13.15%~32.44%，P(2s)峰相对含量显著增加了18.54%~27.02%（p<0.05）。反褶积分峰将P(2s)与O(1s)分为C—P—O，C—O—P，OPO，CO与（或）PO，C—O—C与（或）P—O—C和P—O—P六类。较H₃PO₄改性而言，H₄P₂O₇改性能够促进更多C—O—P，OPO，C—O—C与（或）P—O—C和P—O—P键的形成。改性也使得生物炭中总P含量显著增加，且PA-WBC和PA-CBC中P含量显著高于P-WBC和P-CBC。与WBC和CBC相比，改性处理中活性P含量显著提高2.36~14.77 g·kg-1，稳定态P含量显著降低0.06~0.17 g·kg-1（p<0.05）。与P-WBC和P-CBC相比，PA-WBC和PA-CBC的活性P、中等活性P分别显著增加了5.27~15.66和0.53~0.64 g·kg-1, 稳定态P含量减少了0.03~0.34 g·kg-1（p<0.05）。H₃PO₄和H₄P₂O₇改性改变了P在生物炭表面的结合方式，同时增加了P的活性。H₃PO₄和H₄P₂O₇改性生物炭间，不同形态P含量和结合方式的差异对进一步探究P的生物有效性具有重要意义。     

Sonolytic degradation of acetic acid in aqueous solutions

In this work, ultrasonic degradation of acetic acid, which is one of the most resistant carboxylic acids to oxidize, was investigated. The effects of parameters such as ultrasonic power, initial concentration, addition of NaCl or several oxides were studied on the degradation of acetic acid. Acetic acid was sonicated indirectly using an ultrasonic bath with 40 kHz. It was observed that degradation degree increased with decreasing power and initial concentration and with increasing NaCl concentration. Initial degradation degree was enhanced with addition of zeolite and SiO(2).     

K2O·CaO·4B2O3·12H2O∶Nd3+的合成及发光性能

以CaCl2、K2B4O7和Nd2O3为原料,采用易于工业化、无污染的水溶液法反应合成碱-碱土金属硼酸盐K2O·CaO·4B2O3·12H2O∶Nd3+晶体,利用X射线衍射、红外光谱、扫描电镜、荧光分光度计等现代分析测试手段,对所合成晶体进行了分析和表征.结果表明,所制备的K2O·CaO·4B2O3·12H2O∶Nd3...     

超声波对合成介孔材料Al-MCM-41的有序度的影响

在超声频率为20 kHz,电功率为500 W的超声波作用下,分别以Al（NO₃）₃和Al₂ （SO₄）₃做铝源合成了具有不同Si/Al比的Al-MCM-41。XRD结果显示,尽管超声波作用下,掺杂杂原子Al也要降低介孔材料的有序度,但其有序度降低的程度比普通水热法要小,超声波的辅助可以在同样反应时间内得到比普通水热法具有更高有序度的Al-MCM-41,即在掺杂过程中,超声波要比普通搅拌有利于介孔材料保持其骨架稳定性。此外考察了超声波作用时间对产品有序度和粒度的影响。     

等离子体放电活化生理盐水杀菌应用研究

等离子体中含有多种活性物种可实现高效安全杀菌,活性物种与生物体相互作用多在水环境下进行.因此等离子体与水的相互作用过程研究掀起了等离子体生物杀菌的新浪潮.本文采用水中阵列放电产生等离子体活化生理盐水,利用所产生的活化生理盐水对大肠杆菌开展了杀菌消毒研究,当等离子体放电时间达到120 s时产生的活化生理盐水与大肠杆菌混合后可使大肠杆菌的存活效率降至0.001%.通过紫外-可见吸收光谱测量及化学氧化还原沉降滴定表明放电电荷及激发态氧化性活性物种与水溶液相互作用,转化为活化生理盐水中长寿命相对稳定存在的H_2O_2和O_3等氧化性物种,与大肠杆菌作用并主导主要杀菌效果.     

Electrical conductivity and defect structure of Mg-doped Cr2O3

The electrical conductivity of Cr₂O₃ nominally doped with 2 mol% MgO has been studied by the four point a.c. technique as a function of the oxygen activity (O₂ + Ar, CO + CO₂ and H₂ + H₂O) in the temperature range 400–1200 °C. It is concluded that Cr₂O₃ doped with MgO is an extrinsic conductor and that the dissolved Mg-dopant is compensated by the formation of electron holes at near atmospheric oxygen pressures and by oxygen vacancies (or possibly interstitial chromium ions) at highly reduced oxygen activities (in CO + CO₂ and H₂ + H₂O gas mixtures). In H₂ + H₂O mixtures Mg-doped chromia also dissolves hydrogen as protons and significantly affects the defect structure and electrical conductivity. The defect structure of the oxide under various conditions is discussed.     

INS investigation on disaccharide/H2O mixtures

New Inelastic Neutron Scattering findings on homologues disaccharides (C₁₂H₂₂O₁₁)/H₂O mixtures are presented. The comparison among the spectra of trehalose, maltose and sucrose/H₂O mixtures, besides evidencing a different destructuring effectiveness on the H₂O hydrogen bond network, and hence different cryoprotectant properties, shows a higher ‘crystallinity’ degree for the trehalose/H₂O system which accounts for its higher ‘rigidity’. This result justifies the better cryptobiotic action of trehalose in respect to maltose and sucrose.     

Density functional theory study of formaldehyde adsorption and decomposition on Co-doped defective CeO_2(110) surface

Formaldehyde as an air pollutant to adverse health effects for humanity has been getting attention. The adsorption and dissociation of formaldehyde(HCHO) on the Co_xCe_(1-x_O_(2-δ)(110) surface were investigated by the density functional theory(DFT) calculations. We calculated the oxygen vacancy formation energy as the function of its site around dopant Co in detail. The results showed that Co doping was accompanied by compensating oxygen hole spontaneous formation.The adsorption configurations and bindings of HCHO at different locations on the Co_xCe_(1-x)O_2(110) were presented.Four possible pathways of oxidation of formaldehyde on the catalytic surface were explored. The results suggested that formaldehyde dissociation at different adsorption sites on the doped CeO_2(110) — first forming dioxymethylene(CH_2O_2)intermediate, and then decomposing into H_2O, H_2, CO_2, and CO molecules. It was found that the presence of cobalt and oxygen vacancy significantly prompted the surface activity of CeO_2.     

不同退火温度的Al_2O_3:C薄膜热释光和光释光性能

α-Al_2O_3:C晶体的热释光和光释光性能优越,但其制备要求高,需高温和高还原气氛.与α-Al_2O_3:C晶体性能接近的α-Al_2O_3:C陶瓷,热释光峰不单一.本文采用两次阳极氧化法在0.5 mol/L的草酸溶液中5℃恒温制备高度均匀有序的多孔Al_2O_3:C薄膜,主要研究不同退火温度对其热释光和光释光特性的影响.结果表明,经不同温度退火后的Al_2O_3:C薄膜均为非晶结构;不同退火温度的Al_2O_3:C薄膜热释光的主发光峰约在310℃左右,符合通用级动力学模型.600℃退火后的Al_2O_3:C薄膜热释光灵敏度最强,其热释光剂量曲线在1-10 Gy范围内具有很好的线性响应,在剂量10-120 Gy范围内出现超线性响应;在相同的辐照剂量下,随着退火温度的升高(≤600℃)光释光的初始发光强度逐渐增强.不同退火温度的Al_2O_3:C薄膜光释光衰减曲线都呈典型的指数衰减且快衰减速率相比α-Al_2O_3:C晶体显著加快.600℃退火后的Al_2O_3:C薄膜光释光灵敏度最强,其光释光剂量响应曲线在1-200 Gy整体上都具有很好的剂量线性关系.与热释光相比,Al_2O_3:C薄膜的光释光具有更宽的线性剂量响应范围.此研究为Al_2O_3:C薄膜作为光释光辐射剂量材料做出了有益的探索.     

Effects of fly ash on NOx removal by pulsed streamers

NO_x removal methods using plasma chemical reactions in nonthermal plasmas have been widely studied. In this paper, the effects of the addition of fly ash on NO_x removal using short-pulsed discharge plasmas are described. Fly ash which had been collected from a coal-burning thermal electrical power plant was used. Experiments were performed using four different mixtures of gases which included NO. These were (N₂+NO), (N₂+NO+O₂), (N₂+NO+H₂O), and (N₂+NO+O₂+H ₂O). These gas mixtures were used either with or without the addition of fly ash. The initial concentration of NO was fixed at 200 ppm (NO parts per million of the gas mixture), The study of the NO_x (NO+NO₂) removal was performed with the fly ash, as it is relevant to real situations in coal power plants. The results show that the presence of fly ash decreased the NO_x removal rate slightly in the case of dry gas mixtures while it increased the NO_x removal rate substantially in the case of wet gas mixtures. These results suggest that the presence of fly ash in the flue gases, which also contain a few percentages of moisture, would be advantageous to the treatment of flue gases emitted from thermal power plants for the removal of nitrogen oxides     

Characterisation of (17)O-enriched alumina from a new hydrothermal preparation

A novel method for the hydrothermal synthesis of ¹⁷O-enriched -Al₂O₃ is presented. Its advantage compared to commonly used methods is that Al₂O₃ is directly produced from metallic Al and ¹⁷O-enriched H₂O without formation of intermediate Al-hydroxide phases that require subsequent dehydration. This is a much more efficient use of the ¹⁷O label as the Al₂O₃ has similar ¹⁷O enrichment level as the H₂O initially used.     

Eu,Dy共掺杂SrAl2O4长余辉材料制备新工艺

活化Al-Sr合金粉末水解制备SrAl₂O₄长余辉材料的前驱体,并采用高温固相反应法制备出Eu,Dy共掺杂的SrAl₂O₄长余辉材料,对其微观结构和发光特性进行了研究。实验结果表明:前驱体中Al、Sr元素在微观状态下分布均匀,所制成的长余辉发光材料的发射主峰位于520nm附近,为典型的Eu²⁺离子4f5d-4f的特征发射,初始亮度达到18cd/m²,余辉时间长达46h。     

Performance and reliability improvement of La_2O_3/Al_2O_3 nanolaminates using ultraviolet ozone post treatment

La-based binary or ternary compounds have recently attracted a great deal of attention as a potential candidate to replace the currently used Hf-based dielectrics in future transistor and capacitor devices for sub-22 generation. However, the hygroscopic nature of La₂O₃ hampers its application as dielectrics in electron devices. To cope with this challenge, ultraviolet (UV) ozone post treatment is proposed to suppress the moisture absorption in the H₂O-based atomic layer deposition (ALD) La₂O₃/Al₂O₃ nanolaminates which is related to the residual hydroxyl/hydrogen groups after annealing. The x-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (AFM) results indicate that the moisture absorption of the H₂O-based ALD La₂O₃/Al₂O₃ nanolaminates is efficiently suppressed after 600 ℃ annealing, and the electrical characteristics are greatly improved.