共查询到20条相似文献，搜索用时 0 毫秒
1.
2.
铅对铽离子与钙调素 (Ca M)所形成的配合物 (Tb4· Ca M)的荧光具有熄灭作用。在 p H=5 .5的 HAc-Na Ac缓冲溶液中 ,不断通入 N2 防止 O2 干扰 ,建立了测定 Pb2 的新方法。 Pb2 浓度在 0 .0 92 5—16 .5 6 μg/ m L范围内与 ΔIF 具有良好的线性关系 ,检出限为 0 .0 6 3μg/ m L,相对标准偏差为 2 .6 %。实验考察了共存常见离子的干扰。该法用于精锡矿中铅含量的测定 ,平均回收率为 97.2 %。结果满意。 相似文献
3.
合成了荧光试剂水杨醛缩邻氨基苯酚,在NH4Cl-NH3·H2O缓冲溶液介质中,铅离子能使其荧光强度增强,荧光增强的程度随铅离子含量的增加而增大.据此建立了测定痕量铅离子的直接荧光分析方法.并研究此试剂与铅荧光反应的最佳条件,在λex/λem=386/502nm处,铅离子含量在0.0-200.0μg·L-1范围内与△F呈良好的线性关系,方法的检出限为1.62μg·L-1.该方法操作简便快速,具有极高的灵敏度.用于蓄电池废水中铅含量的测定,结果与火焰原子吸收光谱法基本一致,效果令人满意. 相似文献
4.
5.
6.
为了建立一套高灵敏和低成本的液体样品金属元素检测分析方法,设计制造了一套超声波雾化辅助电火花击穿光谱(UN-SIBS)的实验系统。利用超声波雾化装置将液体样品转化为密集小液滴组成的气溶胶,并使用高压放电线圈和铜电极击穿气溶胶样品诱导等离子体,通过采集分析光谱信号实现对样品金属成分的分析。实验研究了该方法的发射光谱谱线特性,对等离子体的电子温度和密度等物理特性参数进行了计算分析。针对含有不同浓度重金属铅(Pb)元素的样品,在较大的浓度范围内绘制了Pb元素261.37 nm处的原子峰强度随质量浓度变化的曲线。实验结果显示,UN-LIBS方法对Pb元素检测限不高于2.07 ppt,优于同类方法所报道的检测限。同时,与金属活性相对较低的钙(Ca)元素SIBS检测结果进行了比较,分析了UN-SIBS方法的相关机理。 相似文献
7.
8.
9.
Microcystis aeruginosa, as a typical alga, produces microcystin with strong liver toxicity, seriously endangering the liver health of human and animals. Inhibiting the bloom of the Microcystis aeruginosa in lakes becomes a significant and meaningful work. Ultrasonic cavitation is currently considered to be the most environmentally friendly and effective method for the removal of Microcystis aeruginosa. However, the commercialized ultrasonic algae removal systems require multi-Langevin transducers to achieve omnidirectional ultrasonic irradiation due to the single irradiation direction of the Langevin transducer, resulting in the complex design and high energy consumption. To achieve a low-cost, simple structure, and high-efficiency algae removal system, a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa is proposed. The proposed system is major composed of a novel omnidirectional ultrasonic transducer, which generates the omnidirectional ultrasonic irradiation by its shaking-head motion coupled by two orthogonal bending vibration modes. Modal simulation, sound field simulation, and cavitation bubble radius simulation are first carried out to optimize the geometric sizes of the proposed transducer and verify the correctness of the omnidirectional ultrasonic irradiation principle. Then the vibration characteristics of the transducer prototype are measured by vibration tests and impedance tests. Finally, the feasibility and effectiveness of the proposed omnidirectional ultrasonic removal system for Microcystis aeruginosa are evaluated through the algae removal experiments. The experimental results exhibit that the algal cells damaged by ultrasonic irradiation from the proposed system do not have the ability to self-repair. In addition, the algal removal rates reached 55.41% and 72.97% after 30 min of ultrasonic treatment when the corresponding ultrasonic densities are 0.014 W/mL and 0.021 W/mL, respectively. The proposed omnidirectional ultrasonic algae removal system significantly simplifies the configuration and reduces energy consumption, presenting the potential promise of algae removal and environmental protection. 相似文献
11.
合成了离子交换纤维交研究了它们的红外光谱,得到了一些有价值的结果。 相似文献
12.
In this work, a continuous flow extraction system assisted by ultrasound (US) was developed for the extraction of Cr(III) from residual tanned leather shavings. US energy was delivered into the system by a tubular applicator (clamp-on tube US applicator). The effect of the US energy was investigated at 20 kHz of frequency and electrical input power of 75, 150, 300 and 600 W. Residence time and temperature profile were also evaluated. It was observed that the internal temperature profile was affected by the presence of US and inverted in comparison with the conditions without US. In this way, the temperature profile generated by the US was reproduced by using electrical resistances in order to compare the obtained results. The US intensity was measured using a hydrophone connected to a sound pressure meter. The use of the US did not alter the dynamic behavior of the system but increased the extraction efficiency when compared to the silent condition. US power above 75 W did not lead to increased extraction efficiency, when the residence time was 30 min. However, when 60 min of residence time were employed, the optimized US power was 150 W, resulting in an extraction efficiency of 71.7 ± 0.7 %, about 28 % higher when compared to the silent condition in the same temperature and other conditions. The US energy allowed a reduction in processing time and operational temperature when compared to the silent condition with the same temperature profile. The overall energy consumption with US was similar or lower than that observed without US, showing the feasibility of the proposed extraction system. 相似文献
13.
研究了用火焰原子吸收光谱法测钙时PO3- 4对钙的测定的干扰情况以及用有关方法消除PO3-4对钙干扰的效果.用La(NO3)3和EDTA单独消除PO3-4的干扰进行了实验研究,同时对有关问题作了讨论.对测定各种样品中的钙时消除PO3-4的干扰有一定的指导意义. 相似文献
14.
室温下以柠檬酸三纳为稳定剂,在水相中合成了PbS纳米粒子（NP-PbS）。用共振光散射技术（RLS）探索了最佳条件下,体系RLS强度（IRLS）与汞离子浓度在0.001—10μmol/L测定区间内呈现良好的线性（r=0.9941）,据此,建立了测定水中的微量汞的方法。方法的检出限为0.6nmol/L,样品加标平均回收率为100.35%。 相似文献
15.
Surface modification and characterization of Jordanian kaolinite: Application for lead removal from aqueous solutions 总被引：1，自引：0，他引：1
Mohammad Al-Harahsheh Reyad Shawabkeh Adnan Al-Harahsheh Marwan M. Batiha 《Applied Surface Science》2009,255(18):8098-8103
Kaolinite clay was tested for removal of lead ions from aqueous solution. This clay was washed with sulfuric acid solution followed by chemical surface modification using 3-chloropropyltriethoxysilane and sodium hydroxide. XRF results showed that silica to alumina ratio was 2.8:1 for the treated sample compared to 1.6:1 for the raw one.XRD analysis displayed different distinct kaolinite and quartz peaks before treatment while kaolinite peaks were diminished after the treatment. SEM morphology indicated that the raw kaolinite appears as plate structure with no local pores on the plates. However, after treatment the surface was found to have micropores.Different adsorption isotherm models were applied to the experimental data and found that Shawabkeh-Tutunji equation best fit these data adequately. It was also found that chemisorption took place at the surface of the modified kaolinite with maximum adsorption capacity of 54.35 mg/g. 相似文献
16.
Influence of the ultrasound intensity (28 kHz, 1.1–7.5 W/cm2) on CaCO3 nucleation-growth on the surface of a cylinder mild steel electrode rotating at 500 rpm was studied in tap water. The deposition kinetics was analyzed by chronoamperometry; the calcareous layer was characterized by gravimetry, scanning electron microscopy and XRD. Application of ultrasound to calcium carbonate crystallization affects nucleation site density, mass-transport rate and cavitation erosion of the deposits. Lower intensity ultrasound reduces scale porosity and area density by increasing nucleation site density and accelerating the mass transport. Higher intensity ultrasound promotes cavitation erosion of the formed layer, thus cleaning the surface from the scale. A scale layer with the highest blocking properties formed under applied ultrasound intensity of 1.9 W/cm2. The ultrasound doubled crystallization rate, reduced the scale porosity 5 times and halved its area density compared to non-sonicated conditions. Ultrasound of controllable intensity can solve both scale and corrosion problems of industrial heat-exchange equipment by forming a protective scale layer and removing excessive deposits. 相似文献
17.
《Ultrasonics sonochemistry》2014,21(2):735-742
Calcium silicate hydrate (CSH) consisting of nanosheets has been successfully synthesized assisted by a tip ultrasonic irradiation (UI) method using calcium nitrate (Ca(NO3)·4H2O), sodium silicate (Na2SiO3·9H2O) and sodium dodecyl sulfate (SDS) in water. Systematic studies found that reaction time of ultrasonic irradiation and concentrations of surfactant (SDS) in the system were important factors to control the crystallite size and morphologies. The products were characterized by X-ray power diffraction (XRD), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrometry (FTIR). The size–strain plot (SSP) method was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the CSH. These characterization techniques revealed the successful formation of a crystalline phase with an average crystallite size of about 13 nm and nanosheet morphology at a reaction time of 10 min UI with 0.2 g SDS in solvent which were found to be optimum time and concentrations of SDS for the synthesis of CSH powders. 相似文献
18.
19.
Nano-structure of a new 0D Pb(II) coordination supramolecular compound, [Pb4(8-Quin)6](ClO4)2(1), L = 8-HQuin = 8-hydroxyquinolin ligand has been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) and elemental analyses. The structure of compound 1 was determined by single-crystal X-ray diffraction. The single crystal X-ray data of compound 1 implies that the Pb+2 ions are five coordinated. Each lead atom is coordinated to nitrogen and oxygen atoms of 8-hydroxyquinolin ligand. Topological analysis shows that the compound 1 is 1,2,3,4,4M12-1net. Nanoparticles of lead(II) oxide have been prepared by calcination of lead(II) coordination polymer at 500 °C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and IR spectroscopy. 相似文献
20.
Nanomaterials with graphene-like structures have many excellent properties different from bulk materials and have become one of the most popular international frontiers in recent years. In this paper, graphene-like molybdenum disulfide materials are prepared by ultrasonic exfoliation method assisted with 1-Dodecanethiol. Double solvent ultrasonic exfoliation is realized by introducing chloroform. In addition, the optimal preparation conditions for the preparation of graphene-based molybdenum disulfide are investigated from the aspects of ultrasonic processing time and volume ratio of 1-Dodecanethiol and chloroform. Ultrasonic cleaning instrument is used in the experiment, it’s type is KQ3200E (40KHz, 150 W). Results show that the prepared graphene-like molybdenum disulfide has the highest concentration when the volume ratios of 1-Dodecanethiol and chloroform is 1:1 and ultrasonic processing time is 12 h. The dispersion of graphene-like molybdenum disulfide in low-boiling organic solvents, such as chloroform, tetrahydrofuran (THF), isopropanol (IPA), acetone, acetonitrile (CH3CN) and ethanol, is realized by solvent exchange method. Characterized by transmission electron microscopy, a relatively thin sheet material is obtained. In addition, the latest methods for preparing graphene-like molybdenum disulfide nanosheet are discussed in view of micromechanical exfoliation, lithium ion intercalation, chemical vapor deposition and chemical synthesis, the advantages and limitations of various preparation methods are compared, the applications of graphene-like molybdenum disulfide nanosheets are also investigated. 相似文献