Nitric Acid

硝酸
  • 文章类型: Journal Article
    针对自主研发的模拟高放废液喷雾煅烧改造处理试验装置,利用有限元分析方法建立了喷雾煅烧的三维多物理场模型。在本文中,模拟高浓度废液为硝酸盐溶液和蔗糖的混合溶液。硝酸盐溶解的主要化学成分为HNO3和NaNO3。将高放废液蒸发煅烧形成氧化物的过程也称为高放废液的预处理或高放废液的转化。在这个实验中,高速喷射的雾化液滴被蒸发,干燥并在煅烧炉中依次煅烧以获得煅烧产物。通过模拟计算,揭示了试验装置内部温度流场和化学反应状态及结果的分布规律。结果表明,在多物理场耦合条件下,化学反应温度对产品的收率有影响。温度与产品浓度呈正相关,温度对NO2产率的影响大于Na2O。同时,在这种化学反应中,反应物(NaNO3和HNO3)的浓度与主要产物(NO2和Na2O)的浓度呈正相关。然而,随着反应物(NaNO3和HNO3)浓度的增加,主要产物(NO2和Na2O)浓度的增加速率降低。
    Aiming at the independent research and development of a simulated high-level waste liquid spray calcination transformation treatment test device, a three-dimensional multi-physical field model of spray calcination was established by means of finite element analysis method. In this paper, the simulated high-level waste liquid is a mixed solution of nitrate solution and sucrose. The main chemical components of nitrate dissolution are HNO3 and NaNO3. The process of evaporation and calcination of high-level waste liquid to form oxides is also called the pretreatment of high-level waste liquid or the conversion of high-level waste liquid. In this experiment, the atomized droplets sprayed at high speed are evaporated, dried and calcined in turn in the calciner to obtain the calcined product. The distribution law of temperature flow field and chemical reaction state and results inside the test device were revealed by simulation calculation. The results show that under the condition of multi-physical field coupling, the chemical reaction temperature has an effect on the yield of the product. The temperature is positively correlated with the product concentration, and the effect of temperature on the yield of NO2 is greater than that of Na2O. At the same time, in this chemical reaction, the concentration of reactants (NaNO3 and HNO3) had a positive correlation with the concentration of main products (NO2 and Na2O). However, the rate of increase in the concentration of the main products (NO2 and Na2O) decreased with the increase of the concentration of the reactants (NaNO3 and HNO3).
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  • 文章类型: Journal Article
    在这项工作中,研究了微波辅助酸处理对温石棉纤维形态和晶体化学特性的影响。低浓度的硝酸(0.2N)用于去除位于其结构八面体片中的Mg2物种,从而引起形成非结晶无定形二氧化硅骨架的结晶化学变化。该骨架保持细长的形态,但其特征是圆形-不锋利的边缘和多孔表面,与温石棉的初始纤维相比,其在应力下的物理阻力降低,有利于降低纤维的致病性。因此,微波辅助酸处理作为一种低成本,快速有效的选择,以避免与石棉废物管理相关的危险。
    In this work, the effect of microwave-assisted acid treatments on the morphological and crystallochemical characteristics of chrysotile fibers is investigated. A low concentration of nitric acid (0.2 N) is used to remove Mg2+-species located in the octahedral sheet of its structure, thereby causing a crystallo-chemical change forming a skeleton of non-crystalline amorphous silica. This skeleton maintains an elongated morphology but characterized by rounded -not sharp-edges and porous surfaces whose physical resistance under stress is reduced when compared with the initial fibers of chrysotile, favoring a lower pathogenicity of the fibers. Thus, microwave-assisted acid treatment rise as a low-cost, fast and effective option in avoiding the dangerousness associated with asbestos waste management.
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  • 文章类型: Journal Article
    元素分析可以在整个细菌和哺乳动物细胞中提供纳摩尔(μg/L)浓度的痕量铁和其他过渡元素,亚细胞区室,生物流体,和组织。迄今为止,最好的分析方法是电感耦合等离子体质谱法(ICP-MS)。我在这里描述了一种非常通用的样品制备方法,仪器设置,方法开发,和分析。该方法可以扩展到生物样品中多达20种常见元素。
    Elemental analysis can provide trace concentrations of iron and other transition elements at nanomolar (μg/L) concentrations in whole bacterial and mammalian cells, subcellular compartments, biological fluids, and tissues. The best method of analysis is by far Inductively Coupled Plasma Mass Spectrometry (ICP-MS). I describe here a very general method for the sample preparation, instrument settings, method development, and analysis. The method can be extended to up to 20 common elements in biological samples.
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  • 文章类型: Journal Article
    一种萃取色谱树脂,通过将双-辛氧基-杯[4]芳烃-单冠-6(BOCMC)浸渍到丙烯酸酯基聚合物载体材料上制备,为从硝酸进料溶液中去除放射性铯(Cs-137)提供了出色的吸收数据。在本研究期间在3MHNO3下获得的>300的重量分配系数(Kd)值是迄今为止报道的最高的,同时使用基于杯-冠-6的萃取色谱树脂材料。先前报道的类似树脂在可比较的进料条件下产生<100的Kd值。吸附的金属离子可以用去离子水有效地解吸。吸收数据的动力学模型表明,薄膜和颗粒内扩散机制同时在Cs离子吸附到BOCMC树脂上。金属离子吸附数据与吸附等温线模型拟合,不符合物理吸附模型的化学吸附,表明杯冠6配体的苯环与Cs离子之间存在pi-pi相互作用。在5个循环之后,树脂的再利用性相当令人满意,并且树脂材料的辐射稳定性非常好,直至500kGy的吸收剂量。柱研究的结果相当令人鼓舞,其中15mL(9个床体积)作为穿透体积,而洗脱在约12个床体积的去离子水中完成。
    An extraction chromatography resin, prepared by the impregnation of bis-octyloxy-calix[4]arene-mono-crown-6 (BOCMC)onto an acrylic ester based polymeric support material, gave excellent uptake data for the removal of radio-cesium (Cs-137) from nitric acid feed solutions. The weight distribution coefficient (Kd) value of >300 obtained during the present study at 3 M HNO3 was the highest reported so far while using a calix-crown-6 based extraction chromatographic resin material. Analogous resin reported previously has yielded a Kd value <100 at comparable feed conditions. The sorbed metal ions could be efficiently desorbed with de-ionized water. Kinetic modeling of the uptake data indicated that both the film and the intra-particle diffusion mechanism are simultaneously operating in the sorption of Cs+ion onto the BOCMC resin. The metal ion sorption data were fitted to the sorption isotherm models and did not conform to the chemisorptions of physisorption models and indicated a pi-pi interaction between the benzene rings of the calix-crown-6 ligand and the Cs+ ion. The reusability of the resins was quite satisfactory after 5 cycles and the radiation stability of the resin material was very good upto an absorbed dose of 500 kGy. The results of column studies were quite encouraging with 15 mL (9 bed volumes) as the breakthrough volume while the elution was complete in about 12 bed volumes of de-ionized water.
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  • 文章类型: Journal Article
    背景:阿拉伯按蚊,冈比亚按蚊的适应性很强的成员,由于其户外咬人和休息行为,对控制工作提出了挑战。因此,室内杀虫剂控制方法对An无效。阿拉伯。此外,A.阿拉伯正在适应污染水域的繁殖,并可能导致城市地区的残留疟疾和疟疾。在了解农村污染物对按蚊的影响方面取得了一些进展,但是人们对城市污染物的影响知之甚少。因此,在这项研究中,酸性污染物[硝酸(HNO3)和盐酸(HCl)]和碱性污染物(无磷酸盐和含磷酸盐的洗涤剂)对两种实验室饲养的An的影响。确定了阿拉伯菌株-一种杀虫剂敏感菌株(SENN)和一种选自SENN的杀虫剂抗性菌株(SENN-DDT)。
    结果:中位致死浓度(LC50)和幼虫暴露对幼虫发育的影响,成人寿命和杀虫剂耐受性进行了评估。就LC50值而言,发现硝酸和含磷酸盐的洗涤剂比HCl和无磷酸盐的洗涤剂更具毒性。洗涤剂暴露(含磷酸盐和无磷酸盐)增加了两种菌株的成年寿命。硝酸减少了SENN和SENN-DDT的幼虫发育时间,而HCl仅在SENN中减少幼虫发育时间。相比之下,含磷酸盐和无磷酸盐的洗涤剂都增加了两种菌株的幼虫发育时间。此外,HNO3和含磷酸盐的洗涤剂增加杀虫剂的耐受性最大。
    结论:两个An。阿拉伯菌株对城市污染物的反应不同。因此,这项研究提供了对An适应的见解。阿拉伯对酸性和碱性城市污染物。©2024作者(S)。害虫管理科学由JohnWiley&SonsLtd代表化学工业学会出版。
    BACKGROUND: Anopheles arabiensis, a highly adaptable member of the Anopheles gambiae complex, poses a challenge for control efforts due to its outdoor biting and resting behaviour. Consequently, indoor insecticide-based control methods are ineffective against An. arabiensis. Furthermore, An. arabiensis are adapting to breeding in polluted waters, and may be contributing to residual malaria and malaria in urban areas. There have been some advances in understanding the effect of rural pollutants on Anopheles mosquitoes, but the effect of urban pollutants is poorly understood. Thus, in this study, the effect of acidic pollutants [nitric acid (HNO3) and hydrochloric acid (HCl)] and alkaline pollutants (phosphate-free and phosphate-containing detergent) on two laboratory-reared An. arabiensis strains - an insecticide susceptible strain (SENN) and an insecticide-resistant strain selected from SENN (SENN-DDT) - were determined.
    RESULTS: The median lethal concentration (LC50) and larval exposure on larval development, adult longevity and insecticide tolerance were evaluated. Nitric acid and phosphate-containing detergent were found to be more toxic than HCl and phosphate-free detergent in terms of LC50 values. Detergent exposure (both phosphate-containing and phosphate-free) increased adult longevity of both strains. Nitric acid reduced larval development time in both SENN and SENN-DDT, whereas HCl reduced larval development time in SENN only. By contrast, both phosphate-containing and phosphate-free detergents increased larval development time of both strains. Furthermore, HNO3 and phosphate-containing detergent increased insecticide tolerance the most.
    CONCLUSIONS: The two An. arabiensis strains responded to urban pollutants differently. Thus, this study provides insight into the adaptation of An. arabiensis to acidic and alkaline urban pollutants. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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  • 文章类型: Journal Article
    爆炸后的核取证能力取决于快速分离放射性核素以提高测量质量的能力。在这项工作中,利用在Eichrom预滤器树脂上负载的三酰基三氟丙酮和1-辛醇开发了萃取色谱树脂。在硝酸和盐酸基质中测试树脂。在硝酸中,树脂能够提取锆,而在盐酸基质中,可以提取铁和镓。在所有测试的酸性条件下,金被保留,但可以用10%硫脲从柱上洗脱。
    Post-detonation nuclear forensics capabilities depend on the ability to rapidly isolate radionuclides to improve measurement quality. In this work an extraction chromatography resin was developed utilizing thenoyltrifluoroacetone and 1-octanol supported on Eichrom prefilter resin. The resin was tested in nitric and hydrochloric acid matrices. In nitric acid the resin was able to extract zirconium, while in hydrochloric acid matrices it was possible to extract iron and gallium. In all acid conditions tested, gold was retained but can be eluted from the column with 10 % thiourea.
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  • 文章类型: Journal Article
    由于年轻工人更喜欢城市劳动,移民到美国和加拿大,墨西哥海岸的芒果收割变得越来越稀少。这种季节性劳动力变得越来越昂贵,当许多果园同时生产水果时,种植者损失增加。在这项研究中,在将粘性糊状物施加到挂在树上的芒果果实的花梗上之后,测试了一种创新的果实分离方法。活性炭或木炭(AC),与不同量的硝酸混合,提供三种名为:轻,中等,和密集。在芒果果实感觉到树冠下方的网前4小时,用刷子将纳米材料涂在果梗/花梗上。芒果分离实验表明,培养基混合物释放果实的效率最高,平均需要2小时。致密的纳米材料将乳胶渗出减少到7%的果实。果实成熟度成为分离时间的关键因素,其次是芒果的重量。
    As young workers prefer urban labors and migrate to USA and Canada, mango harvesting is becoming scarce on Mexican coasts. This seasonal labor is becoming expensive and when many orchards produce fruit simultaneously, grower losses increase. In this research, an innovative fruit detachment method was tested after applying a viscous paste to the pedicel of mango fruits hanging in the tree. Activated carbon or charcoal (AC), was mixed with different amounts of nitric acid to provide three AC composite blends named: light, medium, and dense. The nanomaterial was applied with a brush to the fruit pedicel/peduncle taking up to 4 h before the mango fruits felt to a net below the tree canopy. Mango detachment experiments indicated that the medium blend was the most efficient in releasing the fruit, taking an average of 2 h. The dense nano-material decreased latex exudation to 7% of the fruits. Fruit maturity emerged as a crucial factor for detachment time, followed by mango weight.
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  • 文章类型: Journal Article
    金属离子可以充当酶辅因子并且影响生物化学反应的动力学,所述生物化学反应还可以影响治疗性蛋白质的生物产生和质量属性,例如糖基化。因为样品制备是金属可靠分析的重要步骤,我们比较了通过ICP-MS对生物反应器培养基样品进行金属分析的两种样品制备程序:(i)样品在2%硝酸中稀释(用硝酸处理,TNA);和(ii)将样品与等体积的5%硝酸混合,并在微波中进行密闭容器消化(密闭容器消化,CVD)。在比较TNA和CVD程序之间的提取效率时,CVD在生物反应器培养液上清液样品中显示出更好的Ca和Cu提取率(~30%)和痕量金属中的Ni提取率(~65%)。对于细胞颗粒样品,CVD程序被发现是更好的铁的提取(〜65%以上)的散装金属,次要金属中的锌(约20%以上)和微量金属中的钴(约60%以上)和镍(约45%以上)。两种程序之间的差异小于10%,并且TNA对于从上清液样品和细胞沉淀样品两者定量的所有其他金属更好。当前的研究有助于使全面金属分析方法更加清晰,以监测和维护生物制品生产中的痕量金属含量。
    Metal ions may act as enzyme cofactors and influence the kinetics of biochemical reactions that may also influence the biological production of therapeutic proteins and quality attributes such as glycosylation. Because sample preparation is a significant step in the reliable analysis of metals, we compared two sample preparation procedures for metal analysis of bioreactor culture media samples by ICP-MS: (i) samples were diluted in 2 % nitric acid (treatment with nitric acid, TNA); and (ii) samples were mixed with equal volume of 5 % nitric acid and closed vessel digestion was performed in a microwave (closed vessel digestion, CVD). In the comparison of extraction efficiencies between TNA and CVD procedures, CVD showed better extraction for Ca and Cu among bulk metals (∼30 %) and for Ni among the trace metals (∼65 %) for the bioreactor broth supernatant samples. For the cell pellet samples, the CVD procedure was found to be better for extraction of Fe (∼65 % more) among bulk metals, Zn (∼20 % more) among minor metals and Co (∼60 % more) and Ni (∼45 % more) among trace metals. Differences between the two procedures were less than 10 % and TNA was better for all other metals quantified from both supernatant samples and cell pellet samples. The current study helps bring more clarity to the methodology on comprehensive metal analysis to monitor and maintain trace metal content for biologics production.
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  • 文章类型: Journal Article
    目的:评估各种表面处理和粘合剂对氧化锆基陶瓷与牙本质的粘结强度的有效性。
    方法:对80个氧化锆样品进行了四表面处理方案(喷砂,48%氢氟酸(HF),48%氢氟酸+70%硝酸(HNO3)和不处理(对照),随后将来自每组的样品基于用于胶结的树脂水泥(RelyXU200和G-CemLinkforce)细分为两个子组(n=10)。使粘结的试样经受剪切应力以使用万能试验机测量粘结强度。为了测试八个研究组之间的粘结强度差异,应用Kruskal-Wallis方差分析检验,并比较各组水泥,采用Mann-WhitneyU检验。
    结果:用G-CemLinkforce树脂水泥胶结的48%HF组观察到最高的粘结强度值(16.220±1.574),而对照组RelyX最低(4.954±0.972)。除了48%HF+70%硝酸外,G-Cem水泥在所有表面处理中均显示出比RelyX更高的粘结强度。
    结论:可以推断,48%的HF可以蚀刻氧化锆并产生多孔结构,该多孔结构被证明对粘合有益。
    结论:对美学的不断增长的需求导致用氧化锆基陶瓷代替金属陶瓷材料。然而,氧化锆对各种常规表面处理剂的化学惰性不断挑战研究人员发现一种新的表面处理方案,可以提高氧化锆的结合强度。如何引用这篇文章:YenamandraMS,约瑟夫A,辛格·P,etal.氧化锆的各种表面处理对其对牙本质的粘附性能的影响:体外研究。JContempDentPract2024;25(3):226-230。
    OBJECTIVE: To assess the effectiveness of various surface treatments and adhesives on the bond strength of zirconia-based ceramic to dentin.
    METHODS: Eighty samples of zirconia were subjected to the four-surface treatment protocols (sandblasting, 48% hydrofluoric acid (HF), 48% hydrofluoric acid + 70% nitric acid (HNO3) and no treatment (control) following which the samples from each group were subdivided into two subgroups (n = 10) based on the resin cement employed for cementation (RelyX U200 and G-Cem Linkforce). The bonded specimens were subjected to shear stress to measure the bond strength using Universal testing machine. To test the difference in bond strength among the eight study groups, the Kruskal-Wallis ANOVA test was applied and for comparison between cements in each group, Mann-Whitney U test was applied.
    RESULTS: The highest bond strength values were observed for 48% HF group cemented with G-Cem Linkforce resin cement (16.220 ± 1.574) and lowest for control group-RelyX (4.954 ± 0.972). G-Cem cement showed higher bond strength than RelyX for all surface treatments except 48% HF + 70% nitric acid.
    CONCLUSIONS: It can be inferred that 48% HF can etch zirconia and generate a porous structure that proves to be beneficial for bonding.
    CONCLUSIONS: The increasing demand for esthetics has led to the replacement of metal-ceramic materials with zirconia-based ceramics. However, the chemical inertness of zirconia to various conventional surface treating agents has continuously challenged researchers to discover a new surface treatment protocol that could enhance the bond strength of zirconia. How to cite this article: Yenamandra MS, Joseph A, Singh P, et al. Effect of Various Surface Treatments of Zirconia on its Adhesive Properties to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):226-230.
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  • 文章类型: Journal Article
    本研究使用了一种新的基于X射线荧光(XRF)的分析方法,该方法具有更好的精度和灵敏度,可以评估土壤中的氟浓度。假设使用颗粒合成程序的XRF方法可以轻松可靠地有效分析土壤中的氟浓度。将使用XRF确定的总氟浓度与使用三种不同类型的分析方案-焚烧/蒸馏确定的总氟浓度进行比较,碱性融合,和王水提取程序。在这三个程序中,焚烧/蒸馏程序没有显示出可靠的精确度和重现性。相比之下,使用XRF分析确定的总氟浓度与使用碱性融合和王水提取程序确定的总氟浓度线性相关。根据韩国废物浸出程序和毒性特征浸出程序的结果,土壤和废物中氟的可浸出性与土壤中总氟浓度没有直接关系。风险评估还显示,富含氟的土壤没有显示出非致癌的毒性作用,尽管超过了韩国土壤中总氟浓度的规定水平(800mg/kg)。我们的结果表明,XRF分析与新开发的预处理方法相结合可能是一种有希望的替代方法,可以轻松,快速地确定土壤中的总氟浓度。然而,需要进一步努力评估氟污染土壤中氟的可浸出性及其相关风险。
    This study used a new X-ray fluorescence (XRF)-based analytical method with better precision and sensitivity to evaluate the fluorine concentrations in soil. It was hypothesized that the XRF method with a pellet-synthesizing procedure may effectively analyze the fluorine concentrations in soil with ease and reliability. The total fluorine concentrations determined using XRF were compared with those determined using three different types of analytical protocols-incineration/distillation, alkaline fusion, and aqua regia extraction procedures. Among the three procedures, the incineration/distillation procedure did not show reliable precision and reproducibility. In contrast, the total fluorine concentrations determined using the XRF analysis were linearly correlated with those determined using the alkaline fusion and aqua regia extraction procedures. Based on the results of the Korean waste leaching procedure and toxicity characteristics leaching procedure, the leachability of fluorine from soil and waste was not directly related to total fluorine concentrations in soil. Risk assessment also revealed that the fluorine-rich soils did not show non-carcinogenic toxic effects, despite exceeding the regulation level (800 mg/kg) in South Korea for total fluorine concentrations in soil. Our results suggest that XRF analysis in combination with the newly developed pretreatment method may be a promising alternative procedure for easily and rapidly determining the total fluorine concentration in soil. However, further efforts are needed to evaluate fluorine leachability and its associated risks in fluorine-contaminated soils.
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