Sonocatalytic removal of naproxen by synthesized zinc oxide nanoparticles on montmorillonite

ZnO/MMT nanocomposite as sonocatalyst was prepared by immobilizing synthesized ZnO on the montmorillonite surface. The characteristics of as-prepared nanocomposite were studied by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD) techniques. The synthesized samples were used as a catalyst for sonocatalytic degradation of naproxen. ZnO/MMT catalyst in the presence of ultrasound irradiation was more effective compared to pure ZnO nanoparticles and MMT particles in the sonocatalysis of naproxen. The effect of different operational parameters on the sonocatalytic degradation of naproxen including initial drug concentration, sonocatalyst dosage, solution pH, ultrasonic power and the presence of organic and inorganic scavengers were evaluated. It was found that the presence of the scavengers suppressed the sonocatalytic degradation efficiency. The reusability of the nanocomposite was examined in several consecutive runs, and the degradation efficiency decreased only 2% after 5 repeated runs. The main intermediates of naproxen degradation were determined by gas chromatography–mass spectrometry (GC–Mass).     

Sonocatalytic degradation of Rhodamine B in the presence of C60 and CdS coupled TiO2 particles

CdS-TiO₂ and CdS-C₆₀/TiO₂ were prepared using C₆₀, cadmium acetate dehydrate [(CH₃COO)₂Cd·2H₂O], sodium sulfide (Na₂S·5H₂O) and titanium (IV) n-butoxide by a sol-gel method. The prepared sonocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and transmission electron microscopy (TEM). A rhodamine B (RhB) solution under ultrasonic irradiation was used to determine the catalytic activity. Excellent catalytic degradation of an RhB solution was observed using the CdS-C₆₀/TiO₂ composites under ultrasonic irradiation. C₆₀ coupled CdS-TiO₂ can enhance the Brunauer-Emmett-Teller (BET) surface area and increase the decolorization rate for rhodamine B solution. The results also shows that increase the content of CdS can enhance the catalytic activity.     

Sonocatalytic degradation of methyl orange in the presence of TiO2 catalysts and catalytic activity comparison of rutile and anatase

Rutile and anatase titanium dioxide (TiO(2)) powders were used as sonocatalysts for the degradation of methyl orange which was used as a model compound. Ultrasound was used as an irradiation source. It was found that the sonocatalytic degradation ratios of methyl orange in the presence of TiO(2) powder were much better than ones without any TiO(2), but the sonocatalytic activity of rutile TiO(2) particles was obviously higher than that of anatase TiO(2) particles. Although there are many factors influencing sonocatalytic degradation of methyl orange, the experimental results show that the best degradation ratio of methyl orange can be obtained when the experimental conditions of the initial methyl orange concentration of 10 mg/l, rutile TiO(2) added amount of 500 mg/l, ultrasonic frequency of 40 kHz, output power of 50 W, pH=3.0 and 40 degrees C within 150 min were adopted. In addition, the catalytic activity of reused rutile TiO(2) catalyst was also studied and found to be better than new rutile TiO(2) catalyst sometimes. All experimental results indicated that the method of the sonocatalytic degradation of organic pollutants in the presence of TiO(2) powder was an advisable choice for treating non- or low-transparent organic wastewaters.     

Sonocatalytic facilitation of hydroxyl radical generation in the presence of TiO2

The generation of hydroxyl (OH) radicals was investigated during ultrasonic irradiation and in the presence of TiO(2). The effect of TiO(2) on an ultrasonic system's oxidation power was evaluated by examining the oxidation of salicylic acid. The generation of the salicylic acid derivatives, 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA, was measured by high-performance liquid chromatography coupled with electrochemical detection under different experimental conditions. The presence of TiO(2) enhanced the generation of DHBA during ultrasonic irradiation, thus indicating a higher oxidation power in the ultrasonic system. Al(2)O(3) also increased the generation of DHBA during irradiation; however, the effect of TiO(2) was found to be higher than that of Al(2)O(3). The addition of OH radical scavengers such as dimethylsulfoxide (DMSO), methanol and mannitol significantly suppressed the production of DHBA, and DMSO was found to have the highest suppressive effect among all scavengers. The effects of dissolved gases on the generation of OH radicals were further studied, and their power was found to be in the order Xe > Ar > O(2) > N(2). The degassing of the irradiation solution completely suppressed the generation of OH radicals. These results indicate that the presence of TiO(2) accelerates the generation of OH radicals during ultrasonic irradiation, and that the process may be mediated through the induction of cavitation bubbles in irradiating solutions.     

Synthesis of flower-like MoS2/CNTs nanocomposite as an efficient catalyst for the sonocatalytic degradation of hydroxychloroquine

Contamination of water resources by pharmaceutical residues, especially during the time of pandemics, has become a serious problem worldwide and concerns have been raised about the efficient elimination of these compounds from aquatic environments. This study has focused on the development and evaluation of the sonocatalytic activity of a flower-like MoS₂/CNTs nanocomposite for the targeted degradation of hydroxychloroquine (HCQ). This nanocomposite was prepared using a facile hydrothermal route and characterized with various analytical methods, including X-ray diffraction and electron microscopy, which results confirmed the successful synthesis of the nanocomposite. Moreover, the results of the Brunauer–Emmett–Teller and diffuse reflectance spectroscopy analyses showed an increase in the specific surface area and a decrease in the band gap energy of the nanocomposite when compared with those of MoS₂. Nanocomposites with different component mass ratios were then synthesized, and MoS₂/CNTs (10:1) was identified to have the best sonocatalytic activity. The results indicated that 70% of HCQ with the initial concentration of 20 mg/L could be degraded using 0.1 g/L of MoS₂/CNTs (10:1) nanocomposite within 120 min of sonocatalysis at the pH of 8.7 (natural pH of the HCQ solution). The dominant reactive species in the sonocatalytic degradation process were identified using various scavengers and the intermediates generated during the process were detected using GC–MS analysis, enabling the development of a likely degradation scheme. In addition, the results of consecutive sonocatalytic cycles confirmed the stability and reusability of this nanocomposite for sonocatalytic applications. Thus, our data introduce MoS₂/CNTs nanocomposite as a proficient sonocatalyst for the treatment of pharmaceutical contaminants.     

Sonocatalytic degradation of methyl parathion in the presence of nanometer and ordinary anatase titanium dioxide catalysts and comparison of their sonocatalytic abilities

The degradation of methyl parathion (O,O-dimethyl-O-(4-nitrophenyl)-phosphorothioate) using anatase titanium dioxide (TiO₂) powder as heterogeneous sonocatalysts is reported. The influences of reaction parameters such as the species of TiO₂ sonocatalysts, methyl parathion concentrations, TiO₂ adding amount, pH, ultrasonic intensity, ultrasonic frequency and temperature have been investigated and the optimal conditions for eliminating methyl parathion have been identified. The efficiencies of sonocatalytic degradation in both nanometer and ordinary anatase systems are compared and the results indicate that the sonocatalytic activity of nanometer anatase TiO₂ powder is better than that of ordinary anatase TiO₂ powder. The primary degradation and the total mineralization of methyl parathion have been monitored by high performance liquid chromatography (HPLC) and UV–vis spectra, respectively. Methyl parathion got destroyed to some extent in both nanometer and ordinary anatase systems under ultrasonic irradiation. The kinetics for the degradation process of methyl parathion follows the first-order reaction. The degradation ratio of methyl parathion surpassed 90% within 50 min in the optimal experiment conditions.     

Mechanically induced changes in amylose structure and effect on thermal behavior in the presence of TiO2 nanoparticles

Thermal behavior of amylose/TiO₂ films under ultrasonic irradiation was investigated, and the final product of each process was applied to prepare amylose/TiO₂ nanocomposite films. The effects of different degradation techniques on thermal behavior, crystallinity, and molecular weight distribution of amylose were surveyed. The evaluations of structural changes and thermal behaviors were performed by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetry analysis, FT-IR spectroscopy, and scanning electron microscopy. The XRD results clarified that the crystalline shape of amylose molecules formed is an A-type crystal due to the sonophotocatalytic processing, while the FT-IR spectra does not approve any chemical change in amylose structure. The DSC data submitted a broad endothermic peak for amylose. In the case of high loading of nanoparticles, the endothermic analysis results and diffraction peaks for the sonophotocatalytic process were not significant. This indicates that the length of amylose chains through the sonophotocatalytic degradation became smaller. An increase at the loading of TiO₂ improved the hydrophilic properties of amylose/TiO₂ films, which leads to the modification of water absorption behavior. Mechanical properties of amylose/TiO₂ films were affected by the uniform dispersion of TiO₂ in the polymer matrix.     

Influence of photo-induced superhydrophilicity of titanium dioxide nanoparticles on the anti-fouling performance of ultrafiltration membranes

Fouling is one of the most present prominent problems in almost all membrane processes. An increase in the membrane hydrophilicity is one of the effective ways to improve the membrane resistance to fouling. In this research, TiO₂ nanoparticles were deposited on the surface of composite ultrafiltration (UF) membrane, and then irradiated by ultraviolet (UV) light. The coating of the membrane surface with TiO₂ nanoparticles and radiation with (UV) light led to the considerable increase of hydrophilicity on the membrane surface. The deposition of TiO₂ nanoparticles was carried out through coordinance bonds with OH functional groups of the polymer on the membrane surface. The flux through a coated and (UV) light radiated membrane was increased to a large extent compared to a virgin membrane. In this research, the effect of different concentrations of TiO₂ nanoparticles in the presence and absence of (UV) irradiation was investigated, and the role of increasing of hydrophilicity on the anti-fouling property of membranes was studied. In order to characterize the membranes FTIR, XRD, SEM, water contact angle and cross-flow filtration were employed. This procedure is a useful technique for improvement of hydrophilicity to decrease (increase) fouling (anti-fouling performance) and enhance the permeation of membranes.     

Polymer-templated mesoporous carbons synthesized in the presence of nickel nanoparticles, nickel oxide nanoparticles, and nickel nitrate

Mesoporous carbon composites, containing nickel and nickel oxide nanoparticles, were obtained by soft-templating method. Samples were synthesized under acidic conditions using resorcinol and formaldehyde as carbon precursors, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock co-polymer Lutrol F127 as a soft template and nickel and nickel oxide nanoparticles, and nickel nitrate as metal precursors. In addition, a one set of samples was obtained by impregnation of mesoporous carbons with a nickel nitrate solution followed by further annealing at 400 °C. Wide angle X-ray powder diffraction along with thermogravimetric analysis proved the presence of nickel nanoparticles in the final composites obtained using nickel and nickel oxide nanoparticles, and Ni(NO₃)₂ solution. Whereas, the impregnation of carbons with a nickel nitrate solution followed by annealing at 400 °C resulted in needle-like nickel oxide nanoparticles present inside the composites’ pores. Low-temperature (−196 °C) nitrogen physisorption, X-ray powder diffraction, and thermogravimetric analysis confirmed good adsorption and structural properties of the synthesized nickel-carbon composites, in particular, the samples possessed high surface areas (>600 m²/g), large total pore volumes (>0.50 cm³/g), and maxima of pore size distribution functions at circa 7 nm. It was found that the composites were partially graphitized during carbonization process at 850 °C. The samples are stable in an air environment below temperature of 500 °C. All these features make the synthesized nickel-carbon composites attractive materials for adsorption, catalysis, energy storage, and environmental applications.     

Stability of alteplase in presence of cavitation

Several experimental studies have demonstrated that ultrasound (US) can accelerate enzymatic fibrinolysis and this effect is further enhanced in the presence of ultrasound contrast agents (UCA). Although UCA have been shown to be safe when administered to ischemic stroke patients, safety information of these agents in the thrombolysis setting is limited. Therefore, in this study we investigated potential adverse effects of acoustic cavitation generated by UCA on alteplase (t-PA), the drug used for treatment of ischemic stroke patients. A volume of 0.9 mL of alteplase was dispensed into a custom-made polyester sample tube. For treatments in the presence or absence of cavitation either 0.1 mL Optison or phosphate buffer saline was combined with alteplase. Three independent samples of each treatment group were exposed to ultrasound of 2 MHz frequency at three different peak negative acoustic pressures of 0.5, 1.7, and 3.5 MPa for a duration of 60 min. All treatments were carried out in a cavitation detection system which was used to insonify the samples and record acoustic emissions generated within the sample. After ultrasound exposure, the treated samples and three untreated drug samples were tested for their enzymatic activity using a chromogenic substrate. The insonified samples containing Optison demonstrated cavitational activity proportional to acoustic pressure. No significant cavitation activity was observed in the absence of Optison. Enzymatic activity of alteplase in both insonified groups was comparable to that in the control group. These tests demonstrated that exposure of alteplase to 60 min of 2 MHz ultrasound at acoustic pressures ranging from 0.5 MPa to 3.5 MPa, in the presence or absence of Optison had no adverse effects on the stability of this therapeutic compound.     

Catalytic behavior of nickel nanoparticles: gasborne vs. supported state

To study the pure catalytic activity of metallic nanoparticles, the formation of methane on gasborne Ni nanoparticles, so called aerosol catalysis experiments, were performed. Beside effects typical for the methanation such as poisoning of the particle surface at temperatures above 385°C, the maximum of the catalytic activity was observed for Ni particles of about 14 nm, i.e. in a size range, which is quite uncommon for typical nanoeffects of metallic particles. To clarify, which catalytic phenomena are related to the aerosol state, the same reaction was performed on supported Ni nanoparticles, which were also generated and conditioned in the gas phase and deposited on a SiO₂ surface by thermophoresis. For these supported particles, the same reaction conditions were established as before for the gasborne Ni nanoparticles. However, differences in the mass transport characteristics of educt and product molecules to the particles were encountered and led to lower overall reaction rates. While qualitatively poisoning kinetics and activation energies agreed for both cases, significant differences were observed for the size dependence of the catalytic activity and for the sintering kinetics. The observed shift of the optimum size for the methanation from 14 nm (aerosol) to 25 nm (on support) can be explained by different adsorption enthalpies of the educt gases on aerosol and supported Ni nanoparticles, respectively.     

Enhanced degradation of 2,4-dichlorophenol by ultrasound in a new Fenton like system (Fe/EDTA) at ambient circumstance

This study investigated the effect of ultrasound (US) enhancement on the degradation of 2,4-DCP in a new Fenton like system. An obviously synergistic effect was observed after introduction of US into the Fe/EDTA system. Good correspondences with pseudo-first-order kinetic were found in each reaction system. It was demonstrated that the degradation rate constant (k_obs) of DCP in US/Fe/EDTA was 7 and 32 times higher than those in Fe/EDTA and US system alone. Simultaneously, lower first-order k_obs was also obtained in the investigation of decomposition of EDTA. At 60 min reaction time, Removals of 81% TOC, complete DCP and 89% EDTA were achieved. Low molecular weight organic acids are identified as the main products, which contribute to the solution self-buffer at about pH 6.5 along with the reaction. In addition, the effect of initials condition, i.e., iron addition, EDTA dosage, DCP concentration and US input power as well as reaction temperature were studied and reaction activation energy (E_a) was also calculated.     

Effect of nano-titanium hydride on formation of multi-nanoporous TiO2 film on Ti

The effect of titanium hydride on the formation of nanoporous TiO₂ on Ti during anodization has been investigated by X-ray photoelectron spectroscopy, grazing incident X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Titanium hydride (TiH₂) was formed after cathodization, profoundly impacting the formation of nanoporous TiO₂ on Ti by anodization. Oxide layer and nanocrystal structure were observed after anodization with cathodic pretreatments. A multi-nanoporous TiO₂ layer was formed on the titanium. The titanium hydride is a nanostructure. The nanostructure is directly changed to nanoporous TiO₂ by a dissolution reaction during anodization. The nanoporous layer is difficult to form without cathodization. The nanostructural TiH₂ is important in forming a nanoporous TiO₂ layer. Anodization treatment with cathodic pretreatment not only yields a titanium surface with a multi-nanostructure, but also transforms the titanium surface into a nanostructured titanium oxide surface.     

Photocatalytic,sonocatalytic and sonophotocatalytic degradation of Rhodamine B using ZnO/CNTs composites photocatalysts

A series of ZnO nanoparticles decorated on multi-walled carbon nanotubes (ZnO/CNTs composites) was synthesized using a facile sol method. The intrinsic characteristics of as-prepared nanocomposites were studied using a variety of techniques including powder X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), transmission electron microscope (TEM), scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX), Brunauer Emmett Teller (BET) surface area analyzer and X-ray photoelectron spectroscopy (XPS). Optical properties studied using UV–Vis diffuse reflectance spectroscopy confirmed that the absorbance of ZnO increased in the visible-light region with the incorporation of CNTs. In this study, degradation of Rhodamine B (RhB) as a dye pollutant was investigated in the presence of pristine ZnO nanoparticles and ZnO/CNTs composites using photocatalysis and sonocatalysis systems separately and simultaneously. The adsorption was found to be an essential factor in the degradation of the dye. The linear transform of the Langmuir isotherm curve was further used to determine the characteristic parameters for ZnO and ZCC-5 samples which were: maximum absorbable dye quantity and adsorption equilibrium constant. The natural sunlight and low power ultrasound were used as an irradiation source. The experimental kinetic data followed the pseudo-first order model in photocatalytic, sonocatalytic and sonophotocatalytic processes but the rate constant of sonophotocatalysis is higher than the sum of it at photocatalysis and sonocatalysis process. The sonophotocatalysis was always faster than the respective individual processes due to the more formation of reactive radicals as well as the increase of the active surface area of ZnO/CNTs photocatalyst. Chemical oxygen demand (COD) of textile wastewater was measured at regular intervals to evaluate the mineralization of wastewater.     

The effect of the deposition parameters on size, distribution and antimicrobial properties of photoinduced silver nanoparticles on titania coatings

Controlled photodeposition of silver nanoparticles (AgNP) on titania coatings using two different sources of UV light is described. Titania (anatase) thin films were prepared by the sol-gel dip-coating method on silicon wafers. AgNPs were grown on the titania surface as a result of UV illumination of titania films immersed in aqueous solutions of silver nitrate. UV xenon lamp or excimer laser, both operating at the wavelength 351 ± 5 nm, was used as illumination sources. The AFM topography of AgNP/TiO₂ nanocomposites revealed that silver nanoparticles could be synthesized by both sources of illumination, however the photocatalysis carried out by UV light from xenon lamp illumination leads to larger AgNP than those synthesized using the laser beam. It was found that the increasing concentration of silver ions in the initial solution increases the number of Ag nanoparticles on the titania surface, while longer time of irradiation results the growth of larger size nanoparticles. Antibacterial tests performed on TiO₂ covered by Ag nanoparticles revealed that increasing density of nanoparticles enhances the inhibition of bacterial growth. It was also found that antibacterial activity drops by only 10-15% after 6 cycles compared to the initial use.     

EDTA滴定法测定草酸中硫酸根

在马弗炉(200℃)灼烧至草酸全部挥发,滴加(1 1)盐酸,使刚果红试纸由红变蓝色(或调节pH到4左右),除去二氧化碳。加入钡镁混合液,沉淀6h(或放置过夜)。加入(1 1)氨水调节pH值约为8—9,加入10mL氨-氯化铵缓冲溶液,2滴铬黑T指示剂,用EDTA标准溶液滴定SO2-4含量。     

EDTA、DTPA与6氨-基青霉烷酸衍生物的合成

乙二胺四乙酸二酐（EDTAD）和二乙三胺五乙酸二酐（DTPAD）分别与6氨-基青霉烷酸（6-APA）反应,合成了两个新的化合物EDTA-6-APA和DTPA-6-APA。通过UV、IR、1H NM R、元素分析对化合物的组成和结构进行了初步表征。探讨了反应物的配比、反应温度、反应时间等反应条件对产物收率的影响。结果表明,最佳合成条件为：n（酸酐）∶n（6-APA）=1∶2,反应温度25℃,反应时间7h,此时产物收率均达到70%以上。     

Synthesis and self-assembly of magnetic nanoparticles

We report the synthesis and self-assembly of different shapes and sizes of FePt nanoparticles. Our study shows that surfactants and solvent play an important role in the synthesis of different shapes and sizes of FePt nanoparticles. Higher boiling point solvents lead to the formation of spherical nanoparticles and low boiling point solvents form cubic nanoparticles. Our studies also indicate that self-assembly of FePt nanoparticles on substrates is a complex process that is sensitive to the concentration of excess surfactant in the nanoparticle solution.     

Periodate-assisted pulsed sonocatalysis of real textile wastewater in the presence of MgO nanoparticles: Response surface methodological optimization

The improvement of sonocatalytic treatment of real textile wastewater in the presence of MgO nanoparticles was the main goal of the present study. According to our preliminary results, the application of pulse mode of sonication, together with the addition of periodate ions, produced the greatest sonocatalytic activity and consequently, the highest chemical oxygen demand (COD) removal efficiency (73.95%) among all the assessed options. In the following, pulsed sonocatalysis of real textile wastewater in the presence of periodate ions was evaluated response surface methodologically on the basis of central composite design. Accordingly, a high correlation coefficient of 0.95 was attained for the applied statistical strategy to optimize the process. As results, a pulsed sonication time of 141 min, MgO dosage of 2.4 g/L, solution temperature of 314 K and periodate concentration of 0.11 M gave the maximum COD removal of about 85%. Under aforementioned operational conditions, the removal of total organic carbon (TOC) was obtained to be 63.34% with the reaction rate constant of 7.1 × 10⁻³ min⁻¹ based on the pseudo-first order kinetic model (R² = 0.99). Overall, periodate-assisted pulsed sonocatalysis over MgO nanoparticles can be applied as an efficient alternative process for treating and mineralizing real textile wastewater with good reusability potential.     

Gd2O3:Eu纳米晶的制备及其光谱性质研究

以EDTA为络合剂,聚乙二醇为有机分散剂,用络合溶胶—凝胶法制备出Gd2O3:Eu纳米晶。用XRD,SEM,X—射线能量色散谱仪(EDS),荧光分光光度计等分析手段对Gd2O3:Eu的纳米晶结构、形貌、组分的均匀性以及发光特性进行了研究。结果表明：EDTA—M凝胶仅在800℃焙烧即可得到颗粒细小、组分均匀、纯立方相的Gd2O3:Eu纳米晶,颗粒基本呈球形,粒径为30nm左右。对样品的激发光谱、发射光谱测定表明：Gd2O3:Eu纳米晶在269nm光激发下发红光,发射光谱谱峰在611nm,与体材料基本相同;激发光谱中电荷迁移带(CTB)明显红移,从体材料的255nm移至269nm,移动了约14nm;猝灭浓度从体材料的6％提高到8％。