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1.
This paper describes the ultrasonic degradation of oxalic acid. The effects of ultrasonic power, H2O2, NaCl, external gases on the degradation of oxalic acid were investigated. Reactor flask containing oxalic acid was immersed in the ultrasonic bath with water as the coupling fluid. Representative samples withdrawn were analysed by volumetric titration. Degradation degree of oxalic acid increased with increasing ultrasonic power. It was observed that H2O2 has negative contribution on the degradation of oxalic acid and there was an optimum concentration of NaCl for enhancing the degradation degree of oxalic acid. Although bubbling nitrogen gave higher degradation than that for bubbling air, both gases (for 20 min before sonication and during sonication together) could not help to enhance the degradation of oxalic acid when compared with the degradation without gas passage.  相似文献   

2.
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.  相似文献   


3.
Water-soluble CdTe nanocrystals (NCs) were synthesized and applied to study the effect of metal ions on chemiluminescence (CL) of the CdTe/H2O2 system. The effects of experimental factors, such as pH, particle sizes of CdTe and reagent concentration, on kinetics curve and CL intensity of the CdTe/H2O2 system were examined. The results showed that under the optimal conditions Ba2+, Ca2+, Fe2+, Pb2+ and Cu2+ enhanced the CL intensity, and Cr3+, Ni2+, Zn2+ and Ag+ inhibited the CL intensity.  相似文献   

4.
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...  相似文献   

5.
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。  相似文献   

6.
王学扬  齐志华  宋颖  刘东平 《物理学报》2016,65(12):123301-123301
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.  相似文献   

7.
Fe3O4磁性纳米颗粒的催化性能研究进展   总被引:1,自引:0,他引:1  
刘文  魏志鹏  郑龙珍 《光谱实验室》2012,29(4):1956-1959
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。  相似文献   

8.
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.  相似文献   

9.
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.  相似文献   

10.
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IG/ID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。  相似文献   

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