光谱法研究纳米二氧化硅(SiO_2)催化超声波照射对牛血清白蛋白(BSA)的损伤

利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义.     

Frequency and power dependence of ultrasonic degassing

We investigated the time variation of ultrasonic degassing for air-saturated water and degassed water with a sample volume of 100 mL at frequencies of 22, 43, 129, 209, 305, 400, 514, 1018, and 1960 kHz and ultrasonic power of 15 W. Ultrasonic degassing was evaluated by dissolved oxygen concentration. Ultrasonic degassing was also investigated at a frequency of 1018 kHz and ultrasonic powers of 5, 10, 15, and 20 W. The dissolved oxygen concentration varied with the ultrasonic irradiation time and became constant after prolonged ultrasonic irradiation. The constant dissolved oxygen concentration value depended on the frequency and ultrasonic power but not the initial dissolved oxygen concentration. The degassing rate at 101.3 kPa was higher in the frequency range of 200 kHz to 1 MHz. The frequency dependence of the degassing rate was almost the same as that of the sonochemical efficiency obtained by the potassium iodide (KI) method. Ultrasonic degassing in the frequency range of 22–1960 kHz was also investigated under reduced pressure of 5 kPa. Degassing was accelerated when ultrasonic irradiation was applied under reduced pressure. However, under a reduced pressure of 5 kPa, the lower the frequencies, the higher is the degassing rate. The sonochemical reaction rate was examined by the KI method for varying dissolved air concentrations before ultrasonic irradiation. Cavitation did not occur when the initial dissolved oxygen concentration was less than 2 mg·L⁻¹. Therefore, the lower limit of ultrasonic degassing under 101.3 kPa equals 2 mg·L⁻¹ dissolved oxygen concentration. A model equation for the time variation of dissolved oxygen concentration due to ultrasonic irradiation was developed, and the degassing mechanism was discussed.     

室温下超声波辐照制备介孔结构的TiO2及其光催化性能

在室温条件下,利用超声波辐照方法合成了一系列具有大比表面积的介孔结构TiO₂光催化剂。应用N₂-物理吸附、X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等手段对合成的样品进行了表征。考察了超声波强度、发射时间对TiO₂的结晶度、比表面积、孔体积、孔径等物理结构的影响,并提出了超声波辐照下TiO₂的介孔结构的形成机理。以λ=365 nm的紫外光为光源,评价了该系列催化剂光催化降解染料甲基橙的性能。结果表明超声波功率的增加将增加TiO₂的结晶度和孔径,并使其晶粒发生细化,提高催化剂的分散性。声化学合成的样品具有较高的光催化活性,其主要原因是超声波辐照方法合成的TiO₂具有较高的结晶度和较大的比表面积和孔体积。     

Sonochemical effect and pore structure tuning of silica xerogel by ultrasonic irradiation of semi-solid hydrogel

Silica xerogels were prepared by the sol-gel method under ultrasonic irradiation, using tetraethylorthosilicate (TEOS) as the starting material. Hexamethyldisiloxane (HMDSO) was used as the hydrophobizing agent. When preparing silica xerogel, it is necessary to perform aging and hydrophobization to suppress shrinkage during ambient pressure drying, however, such treatments are time-consuming. In this study, the semi-solid hydrogel was irradiated with ultrasonic for the first time in order to accelerate aging and hydrophobic treatment, and the effect of ultrasonic frequency on structure was investigated. Firstly, ultrasonic irradiation was performed at frequencies of 100 kHz and 500 kHz, followed by hydrophobic treatment at a frequency of 500 kHz, in order to promote aging. The results identify optimum conditions for ultrasonic irradiation to promote aging and hydrophobization reactions, and it was found to be possible to prepare silica xerogels in less than 1/5 of the conventional time. The silica xerogels had a low density and the shrinkage was suppressed. In this study, it was found that ultrasonic irradiation of semi-solid hydrogel was very effective for promoting the reaction.     

Quantification of ultrasonic intensity based on the decomposition reaction of porphyrin

A simple method is proposed for quantification of the effective ultrasonic intensity in the reaction vessel based on the decomposition reaction of 5,10,15,20-tetrakis(4-sulfotophenyl) porphyrin (H₂TPPS⁴⁻). The change of concentration of porphyrin in solution irradiated by the ultrasound wave depends on the irradiation time and the output power of ultrasound generator. The decomposition ratio of porphyrin is defined as the ratio of the concentration of porphyrin after ultrasonic irradiation to that before ultrasonic irradiation. A linear relationship between the decomposition ratio of porphyrin and the concentration Fe³⁺ in the Fricke solution under sonication was obtained. The decomposition ratio was related to the absorption dose in radiation chemistry.     

Ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock

A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9 min of ultrasonic irradiation (20 kHz, 750 W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.     

Comparative study of lignins isolated by alkali and ultrasound-assisted alkali extractions from wheat straw.

Treatment of the dewaxed wheat straw with 0.5 M KOH at 35 degrees C for 2.5 h without ultrasonic irradiation and with ultrasound assistance for 5, 10, 15, 20, 25, 30, and 35 min resulted in a dissolution of 43.9%, 43.9%, 43.9%, 44.4%, 44.4%, 45.6%, 46.8%, and 49.1% of the original lignin, respectively. Much better results were achieved under the ultrasonic irradiation time for 35 min where nearly 50% of the original lignin was solubilized at 35 degrees C for 2.5 h. The purity of the lignin preparations isolated by alkali with ultrasound assistance was higher than that of the lignin fraction obtained by alkali without ultrasonic irradiation, and their purity increased with an increment of irradiation time between 5 and 35 min, in which the content of associated polysaccharides in the former lignin preparations (0.87-1.06%) was lower than that of the latter lignin fraction (1.16%). In addition, the lignins isolated by alkali with ultrasonic irradiation time between 5 and 30 min showed a slightly higher molecular weight and thermal stability than the lignin obtained by alkali without ultrasound assistance. No substantial differences in the main structure features between the lignin preparations isolated by alkali and ultrasound-assisted alkali extractions were found.     

Investigation on damage of DNA molecules under irradiation of low frequency ultrasound in the presence of hematoporphyrin-gallium (HP-Ga) complex

The interaction of deoxyribonucleic acid (DNA) and hematoporphyrin–gallium (HP–Ga) complex and the damage of DNA under ultrasonic irradiation in the presence of HP–Ga complex were studied by means of UV–vis spectrum, fluorescence spectrum and gelatin electrophoresis. In addition, some influence factors such as ultrasonic irradiation time, HP–Ga complex concentration, ionic strength and solution acidity on the damage of DNA were also considered. Under a certain condition, the damage degree of DNA was enhanced with increasing ultrasonic irradiation time, HP–Ga complex concentration and ionic strength. Whether the pH value was too high or too low, it would be disadvantage to the damage of DNA. Perhaps, these results would be significant for driving sonodynamic treatment (SDT) to the clinic application in the future.     

超声辐射油溶性氧化剂氧化燃料油中二苯并噻吩的研究

以油溶性过氧化羟基异丙苯(CHP)为氧化剂,Al2O3为催化剂,引入超声作用,以正辛烷为模拟油品对油中二苯并噻吩的氧化进行了研究。考察了反应温度、反应时间、催化剂用量、氧硫比、超声功率对二苯并噻吩(DBT)降解率的影响并进行了正交实验,结果表明,各因素影响程度大小依次为:反应温度>催化剂用量>超声功率>反应时间>氧硫比,在反应温度为70℃,反应时间为45 min,氧硫比为5:1,催化剂用量为0.3 g,超声功率为60 W的最佳氧化条件下,DBT的降解率达到了88.0%。     

Spectroscopic investigation on the sonodynamic activity of Safranine T to bovine serum albumin damage

In this paper, the Safranine T (ST) was used as sonosensitive compound to study the sonodynamic damage to bovine serum albumin (BSA) under ultrasonic irradiation using fluorescence and UV–vis spectroscopy. The experimental results revealed the obvious synergetic effect of Safranine T (ST) and ultrasonic irradiation during the damage of BSA molecules. In addition, some influencing factors such as ultrasonic irradiation time, Safranine T (ST) concentration, pH value and ionic strength on the sonodynamic damage of BSA molecules were also considered. Finally, the generation of reactive oxygen species (ROS) in sonodynamic process was estimated by the method of Oxidation-Extraction Photometry (OEP). Meanwhile, several radical scavengers were used to determine the kind of generated ROS. Experiments showed that under ultrasonic irradiation the Safranine T (ST) can generate several kinds of ROS at the same time, at least including singlet oxygen (¹O₂) and hydroxyl radicals (OH).     

Using low intensity ultrasound to improve the efficiency of biological phosphorus removal

Low intensity ultrasound can produce various effects on biological materials, such as stimulating enzyme activity, cell growth, biosynthesis, etc., which may improve the efficiency of enhanced biological phosphorus removal (EBPR). We adopt total phosphorus (TP) and dehydrogenase activity (DHA) as indicators to confirm the feasibility of applying low intensity ultrasound in EBPR. Single-factor experiments and orthogonal test were conducted in batch anaerobic/oxic (A/O) process simulation to study the influence of ultrasonic intensity and exposure time in the EBPR process. The results showed that the optimal ultrasonic parameters were 0.2 W/cm² and 10 min under which condition the TP concentration in the effluent was 35–50% lower than that of the control (without ultrasonic irradiation). Changes of sludge activities after ultrasonic irradiation were examined. The improvement of sludge activity by ultrasound took 4 h after irradiation to reach the peak level, when an increase above 50% of DHA has been achieved by ultrasonic irradiation, and the enhancing effects induced by ultrasound disappeared in 16 h after irradiation. A tentative mechanism of biological phosphorus removal enhancement stimulated by ultrasound was discussed based on these phenomena.     

Ultrasound-enhanced extraction of lignin from bamboo (Neosinocalamus affinis): characterization of the ethanol-soluble fractions

Bamboo was submitted to ultrasound-assisted extraction in aqueous ethanol to evaluate the effect of ultrasonic irradiation on the dissolution of lignin. In this case, the dewaxed bamboo culms were subjected to ball milling for 48 h, and then were suspended in 95% ethanol followed by ultrasonic irradiations for varied times at 20 °C to obtain ethanol-soluble fractions. The structural and thermal properties of the ethanol-soluble fractions were comparatively investigated by chemical analysis including alkaline nitrobenzene oxidation, bound carbohydrate determination, FT-IR spectra, HSQC spectra, TG, and DTA. The results showed that the yields of the ethanol-soluble fractions were between 4.29% and 4.76% for the fractions prepared with ultrasonic irradiation time ranging from 5 to 55 min, as compared to 4.02% for the fraction prepared without ultrasonic irradiation. It was found that the lignin content of the fraction increased with the increase of the ultrasonic irradiation time. There was a slight increase of the molecular weight of the lignin with the increase of the ultrasonic irradiation time. Alkaline nitrobenzene oxidation coupled with HSQC analysis indicated that the lignin in the fractions was mainly composed of G S H type units as well as minor amounts of ferulic acids. In addition, the fraction prepared with ultrasonic irradiation exhibited a slightly higher thermal stability as compared to the fraction prepared without ultrasonic irradiation.     

The effect of ultrasonic irradiation on the structure,morphology and photocatalytic performance of ZnO nanoparticles by sol-gel method

In this research, the effect of ultrasonic irradiation power (0, 75, 150 and 200 W) and time (0, 5, 15 and 20 min) on the structure, morphology and photocatalytic activity of zinc oxide nanoparticles synthesized by sol-gel method was investigated. Crystallographic structures and the morphologies of the resultant powders were determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns showed that ZnO samples were crystallized in their pure phase. The purity of samples was increased by increasing the ultrasonic irradiation power and time. Not only did ultrasonic irradiation unify both the structure and the morphology, but also it reduced the size and prohibited particles from aggregation. The optical behavior of the samples was studied by UV–vis spectroscopy. Photocatalytic activity of particles was measured by degradation of methyl orange under radiation of ultraviolet light. Ultrasound nanoparticles represented higher degradation compared to non-ultrasound ones.     

Ultrasonic effects on electroorganic processes--Part 20. Photocatalytic oxidation of aliphatic alcohols in aqueous suspension of TiO2 powder

Ultrasonic effects in a suspension system were examined using the photocatalytic oxidation of 2-propanol to acetone and of ethanol to acetaldehyde in the aqueous suspension of TiO2 powder as a model reaction. The formation rate of acetone was significantly increased under ultrasonic irradiation. The oxidation reaction under ultrasonic irradiation was affected in a different manner from that in silence by reaction conditions such as ultrasonic power, stirring speed, amount of TiO2, concentration of 2-propanol, and pretreatment of the TiO2 powder. Furthermore, it was also observed that the particle size of the TiO2 photocatalyst powder was increased due to the particle agglomeration by ultrasonic irradiation, and consequently it was suggested that ultrasound activates the surface of the catalyst. These results are discussed on the basis of not only the activation of the photocatalyst but also ultrasonic enhancement of mass transport of 2-propanol molecules.     

Iodobenzene diacetate (IBD) catalyzed an quick oxidative aromatization of Hantzsch-1,4-dihydropyridines to pyridines under ultrasonic irradiation

This project was undertaken to demonstrate the potential of iodobenzene diacetate for the oxidative aromatization of Hantzch-1,4-dihydropyridines under ultrasonic irradiation. All reactions were carried out under ultrasonic irradiation and results were compared with traditional method. Sonochemical switching was observed in case of oxidative aromatization of 4-n-alkyl substituted 1,4-DHP. Without sonication, dealkylation occurred in case of n-alkyl substituted 1,4-DHP (ionic mechanism) but under ultrasonic irradiation, n-alkyl group was not expelled (radical mechanism). However, secondary alkyl (isopropyl) and benzyl group were expelled under both conditions.     

Sonochemical synthesis of monodispersed magnetite nanoparticles by using an ethanol–water mixed solvent

The magnetite nanoparticles were synthesized in an ethanol–water solution under ultrasonic irradiation from a Fe(OH)₂ precipitate. XRD, TEM, TG, IR, VSM and UV/vis absorption spectrum were used to characterize the magnetite nanoparticles. It was found that the formation of magnetite was accelerated in ethanol–water solution in the presence of ultrasonic irradiation, whereas, it was limited in ethanol–water solution under mechanical stirring. The monodispersibility of magnetite particles was improved significantly through the sonochemical synthesis in ethanol–water solution. The magnetic properties were improved for the samples synthesized under ultrasonic irradiation. This would be attributed to high Fe²⁺ concentration in the magnetite cubic structure.     

Ultrasound-assisted desalination of crude oil: The influence of mixing extent,crude oil species,chemical demulsifier and operation variables

Coalescence of water droplets in crude oil has been effectively promoted by chemical demulsifiers integrated with ultrasound. Temporary images of water droplets in W/O emulsions were directly monitored using a metallurgical microscope. Water droplets achieved expansion of 118% at 40 min ultrasonic irradiation time under well mixing conditions. However, water droplets in heavy crude oil undergo less aggregation than those in light crude oil, due to resistance of mobility in highly viscous fluid. In the absence of chemical demulsifiers, water droplets enveloped by native surfactants appeared to aggregate arduously because of occurrence of interfacial tension gradients. Influential significance analyses have been executed by a factorial design method on operation variables, including acoustic power intensity, operation temperature, ultrasonic irradiation time and chemical demulsifier dosages. In this work, the outcomes indicate that the optimal operating conditions for desalination of crude oil assisted by ultrasound were as follows: acoustic power intensity = 300 W, operation temperature = 90℃, ultrasonic irradiation time = 75 min and chemical demulsifier dosages = 54 mg/L. Besides, it was found that the most influential importance of operation parameter was temperature, followed with acoustic power intensity, ultrasonic irradiation time and chemical demulsifier dosages.     

Electroless coating of copper on ceramic in an ultrasonic field

The effect of ultrasonic irradiation on electroless copper coating on ceramic in a copper sulphate-potassium sodium tartrate-formaldehyde system was studied in terms of temperature, coating solution composition, acoustic power, frequency and irradiation time with an orthogonal design method in mathematical statistics. Sonication can produce a more uniform and well bonded coating with a faster coating rate compared with a control process. The mechanism of the coating rate increase under sonication is discussed.     

Spectroscopic analyses on interaction of bovine serum albumin (BSA) with toluidine blue (TB) and its sonodynamic damage under ultrasonic irradiation

In this paper, the toluidine blue (TB) with tricyclic quinone imide plane structure is used as sonosensitizer to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by UV-vis and fluorescence spectroscopy. The results show that the TB can bind to BSA molecules, obviously, and the synergetic effects of TB and ultrasonic irradiation can efficiently damage the BSA molecules. Otherwise, some influencing factors such as ultrasonic irradiation time, TB concentration, pH value and ionic strength on the damage of BSA molecules were also considered by the numbers. Synchronous fluorescence spectroscopy indicates that the tyrosine (Tyr) residues of BSA molecules are damaged more seriously than the tryptophan (Trp) residues under ultrasonic irradiation.     

乳化原油的超声波脱水研究

从理论上分析了油中的水滴粒子在超声波辐射下的位移效应,给出了超声波分离油水的理论根据.针对其它物理化学方法不能有效破乳的污水回收油进行了实验,证实了超声波分离乳化原油中油和水的可行性、得到了超声波破乳脱水的声学参数.