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Silver Oxide (Ag2O)-Guar gum nanocomposite was fabricated via a simple sonochemical co-precipitation method. The obtained photocatalyst was characterized with various techniques such as X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, scanning electron microscopy and transmission electron microscopy along with energy dispersion X-ray spectroscopy. The findings have demonstrated that Ag2O nanoparticles are spherical of 5−20 nm and were dispersed on the surface of polysaccharide guar gum to form Ag2O-guar gum nanocomposite. The as-synthesized nanocomposite was enacted as a competent photocatalyst for the reduction of nitrobenzene and oxidation of benzyl alchohol. The conversion efficiency for the reduction of nitrobenzene was 96 % with the addition of sodium borohydride, and the conversion of benzyl alcohol was 98 %. The highly efficient photocatalytic activity was due to the exceedingly dispersed Ag2O-guar gum nanocomposite where effective separation rate of energy driven electron-hole pairs and stronger light absorption occurs. The possible mechanism of the reactions was implicated in understanding the active species involved in the photocatalytic study.

Dicofol, an extensively used organochlorine pesticide and a recommended Stockholm convention persistent organic pollutant (POP) candidate is well known for its endocrine disruptive properties. The sonochemical degradation of Dicofol in aqueous media has been investigated using a 20-kHz probe type sonicator with power inputs from 150 to 450 W. The degradation rate was determined as a function of concentration of Dicofol, solution pH, bulk phase temperature, ultrasonic power density and H2O2 addition. At optimum operating conditions, the pseudo-first-order degradation rate constant (k) was determined to be 0.032 min−1 and the extent of degradation was found to be 86% within 60 min of ultrasound treatment. High performance liquid chromatography (HPLC) and Gas chromatography coupled with mass spectroscopy (GC-MS) analysis indicated the presence of degraded products. The obtained results of Dicofol degradation and control experiments in the presence of H2O2 and radical scavenger test suggest thermal decomposition along with radical attack at bubble-vapor interface to be the dominant degradation pathway. Sonochemical treatment is effective and promising for successful removal of harmful pesticides such as Dicofol and superior removal efficiency for other POPs is expected in the near future with the successful implementation of ultrasound-based wastewater treatment.

The present study investigated the anti-inflammatory and analgesic activities of novel aspirin oil-in-water (O/W) nanoemulsion and water-in-oil-in-water (W/O/W) nano multiple emulsion formulations generated using ultrasound cavitation techniques. The anti-inflammatory activities of nanoemulsion and nano multiple emulsion were determined using the λ-carrageenan-induced paw edema model. The analgesic activities of both nanoformulations were determined using acetic acid-induced writhing response and hot plate assay. For comparison, the effect of pretreatment with blank nanoemulsion and reference aspirin suspension were also studied for their anti-inflammatory and antinociceptive activities. The results showed that oral administration of nanoemulsion and nano multiple emulsion containing aspirin (60 mg/kg) significantly reduced paw edema induced by λ-carrageenan injection. Both nanoformulations decreased the number of abdominal constriction in acetic acid-induced writhing model. Pretreatment with nanoformulations led to a significant increase in reaction time in hot plate assay. Nanoemulsion demonstrated an enhanced anti-inflammatory and analgesic effects compared to reference suspension while nano multiple emulsion exhibited a mild inhibitory effects in the three experimental animal model tests. The results obtained for nano multiple emulsion were relatively lower than reference. However, administration of blank nanoemulsion did not alter the nociceptive response significantly though it showed slight anti-inflammatory effect. These experimental studies suggest that nanoemulsion and nano multiple emulsion produced a pronounced anti-inflammatory and analgesic effects in rats and may be candidates as new nanocarriers for pharmacological NSAIDs in the treatment of inflammatory disorders and alleviating pains.

2-(Trimethylsilyl)ethanol as a new alcohol equivalent has been employed for copper-catalyzed coupling of aryl iodides. Using mild reaction conditions, it has been observed that substituted phenols and phenols with sensitive functional groups can be readily prepared.

Carbamic acid 2-trimethylsilylethyl ester (Teoc-NH 2 ) serves as an ammonia equivalent in the palladium-catalyzed amination of aryl bromides and aryl chlorides. Anilines with sensitive functional groups can be readily prepared using these amine derivatives.

A new approach has been developed for the preparation of Y(OH)3:Eu and Y2O3:Eu nanosheets using the sol–gel method and hydrothermal reactions. XRD patterns showed that the product was purely hexagonal-phase Y(OH)3. TEM images revealed that the nanosheets are square shaped (1 × 1 μm2) with a thickness of several tens of nanometers. In addition, it was found that cubic-phase Y2O3 nanosheets can be obtained by calcination of Y(OH)3 at 900 °C for 1 h. More importantly, the thus-prepared Y(OH)3:Eu and Y2O3:Eu nanosheet phosphors were found to exhibit a relatively high photoluminescence (PL) intensity.

In the past decades, a great deal of attention has been focused on mechanical, thermal or chemical pretreatments of lignocellulosic and algal biomass for the production of biofuel. This chapter is focused on the potential of ultrasound (US) technology in pretreating the biomass to enhance the conversion of cellulose to fermentable sugars and also the disintegration and component extraction of microalgae for the generation of bioethanol or biogas. In addition, US can supplement existing biomass pretreatment methods to greatly enhance their performance and their efficacy. Low frequency ultrasound (LFU, 20–100 kHz) is commonly used in biomass processing, particularly in processes that require intense physical effects such as cell disruption and polymer degradation. High frequency ultrasound (HFU, 400 kHz–2 MHz) recently attracted considerable interest as potential alternative technique for pretreating both the lignocellulosic and algal biomass for sustainable biofuel production. HFU is gaining increasing importance because of its environmentally sound and energy-saving production method since it demands lower energy input for the conversion of biomass. It not only saves time and energy but also lowers the chemical/enzyme dosage and hence novel and considered to be a new sustainable and environmentally-friendly green technique. Although many studies have shown the promise of ultrasound in the cell breakdown for enhanced enzymatic hydrolysis, there is limited information in the application of HFU on biomass pretreatment processes. This chapter provides an overview on the fundamentals of US, the critical parameters that control the conversion of biomass, challenges involved with the application of US in the biomass conversion and its future perspectives.

We report on a simple and novel sonochemical method for the preparation of polyaniline (PANI), as well as its composite, with Au nanoparticles. This technique utilizes ultrasound radiation as an energy source to facilitate the reaction by reducing the reaction time, as well as significantly increasing the yield. The tremendous increase in the reaction rates is explained on the basis of the intensive bubble collapse conditions, which rapidly generate the oxidative radicals necessary for polymerization.

Macroporous alumina materials were synthesized by using yeast cells as bio-templates. Aluminium isopropoxide (AIP) modified with triethanolamine (TEA) was first hydrolyzed by water containing the dispersed yeast cells. This resulted in the formation of slurry consisting of hydrolyzed sol and yeast cells. After centrifuging, the cake which is packed with hydrated sol and yeast cells was subjected to heat treatment. The obtained sample after heat treatment contained finely dispersed pores ranging in size from 1.5 to 2.0 μm. Under the present experimental conditions, the thickness of alumina wall was also controlled by changing the ratio of yeast cells to AIP.

Bimodal (meso/macro) porous alumina materials were synthesized using yeast cells as bio-templates. Aluminium isopropoxide (AIP) modified with triethanolamine (TEA) was first hydrolyzed by water containing the dispersed yeast cells. This resulted in the formation of slurry consisting of hydrolyzed sol and yeast cells. After centrifuging the solution, the obtained cake which is packed with hydrated sol and yeast cells was subjected to heat treatment. The sample after heat treatment contained finely dispersed bimodal (meso/ macro) pores ranging in size from 1.5 to 2.0 μm and several nm. Under the present experimental conditions, the thickness of alumina wall was also controlled by changing the ratio of yeast cells to AIP. It was also observed that with an increase in the thickness of the wall, the size of the pores decreased. [DOI: 10.1380/ejssnt.2005.405]

The present work analyses, in detail, the optimization of a sonochemical process with respect to concentration of precursor and power supplied in a system. This is due to that even a small change in power dramatically changes the high-energy conditions created with the bubble collapse. A model reaction that has been considered for this purpose involves the decomposition of Fe(CO)5 in decalin solvent as this reaction is strongly influenced by the cavitation conditions. Sonochemical treatment of this carbonyl results in the formation of amorphous Fe2O3, which on heat treatment gives nanocrystalline Fe2O3. It has been observed that concentration and power density parameters play an important role to obtain higher decomposition of Fe(CO)5 and hence higher yield of the amorphous Fe2O3 product. Also, using the experimentally observed results, a correlation (polynomial) has been developed.

Nanosized TiO2 supported on activated alumina was prepared using a sonochemical method. To prepare this supported material, direct immersion horn and cup horn ultrasonic systems were used. The efficiency of the sonochemical coating process was determined by UV photodecolourisation of the aqueous methyl orange solution. It was found that TiO2 supported on activated alumina prepared by the sonochemical method gave the maximum decolourisation efficiency. In that method itself, direct immersion horn gave a higher photodecolourisation activity as compared to the cup horn. The obtained results suggest that the direct immersion horn results in uniform, as well as a maximum number of TiO2 particles to be adsorbed on an activated alumina surface.

Sonochemical reactors offer excellent promise in the wastewater treatment applications due to the creation of local hotspots with overall ambient operating conditions and release of highly reactive free radicals. However, its application in the actual industrial practice is hampered by the fact that the existing available information related to the optimization of operating parameters is restricted mainly to small scale operations with reported experiments with capacity in the range of few milliliters to 1 l. With this information, efficient scale up and successful operation of industrial scale reactors is almost impossible. Thus, design of novel large-scale sonochemical reactors and subsequent testing of the same for destruction of different pollutants is the need of the present hour. In an attempt to move one step ahead in the design process, a novel sonochemical reactor with a capacity of 7.5 l has been developed and tested using destruction of Rhodamine B as a model reaction. Effect of various operating parameters such as frequency of irradiation, use of multiple frequencies and power dissipation into the system on the extent of degradation has been studied. Experiments have also been performed with the KI decomposition (model reaction typically used in investigating cavitational effects) so as to establish the dependency of the trends in the variation of the extent of degradation with the operating parameters on the cavitational intensity requirements for a specific application. For the degradation of Rhodamine B, power dissipation into the system was found to be the controlling parameter and the extent of degradation is directly proportional to the power dissipation with a coefficient of 74.1.

A novel method of treating a dye solution has been studied by hydrodynamic cavitation using multiple hole orifice plates. The present work deals with the effect of geometry of the multiple hole orifice plates on the degradation of a cationic dye rhodamine B (rhB) solution. The efficiency of this technique has been compared with the cavitation generated by ultrasound and it has been found that there is substantial enhancement in the extent of degradation of this dye solution using hydrodynamic cavitation. Large-scale operation coupled with better energy efficiency makes this technique a viable alternative for conventional cavitational reactors.

In order to assess the ultrasound dual frequency effects, sonochemical degradation of p-nitrophenol (p-NP) in an aqueous solution has been carried out with ultrasound at three operating frequencies, i.e., at 25, 40 kHz each independently, and the combination of two frequencies (25+40 kHz) simultaneously. Based on the rates of degradation, a kinetic study has been performed which leads to the evaluation of apparent kinetic rate constants for the degradation of p-NP. The influence of various parameters including initial solution pH, bulk solution temperature, on the degradation of p-NP was studied for these three frequency modes (25, 40 and 25+40 kHz) in order to investigate the temporal behaviour of this reaction, especially when it was operated in combined mode (25+40 kHz). The energy efficiency in the case of dual frequency mode is much better than single frequency modes. Modelling and cavity dynamics simulations have also been carried out to explain the observed effects. During combined mode operation, an improvement in the rate of degradation has been observed. The variation in the rate constants has been explained based on the difference in the acoustic pressure field in different systems including ultrasonic bath and dual frequency processor.

Enhancement of the reaction rate by combining the beneficial effects of PTC and ultrasound has been explored in the present study by taking the transformation of benzamide by dehydration to give benzonitrile as a model system. It was found that there is a substantial reduction in the reaction time when ultrasound was coupled with PTC.

In this investigation, an attempt has been made to establish the physical mechanism of sonochemical synthesis of zinc ferrite with concurrent analysis of experimental results and simulations of cavitation bubble dynamics. Experiments have been conducted with mechanical stirring as well as under ultrasound irradiation with variation of pH and the static pressure of the reaction medium. Results of this study reveal that physical effects produced by transient cavitation bubbles play a crucial role in the chemical synthesis. Generation of high amplitude shock waves by transient cavitation bubbles manifest their effect through in situ micro-calcination of metal oxide particles (which are generated through thermal hydrolysis of metal acetates) due to energetic collisions between them. Micro-calcination of oxide particles can also occur in the thin liquid shell surrounding bubble interface, which gets heated up during transient collapse of bubbles. The sonochemical effect of production of OH radicals and H(2)O(2), in itself, is not able to yield ferrite. Moreover, as the in situ micro-calcination involves very small number of particles or even individual particles (as in intra-particle collisions), the agglomeration between resulting ferrite particles is negligible (as compared to external calcination in convention route), leading to ferrite particles of smaller size (6 nm).

Palladium catalyzed coupling of sulfinamide (II) with aryl halides gives sulfinated anilines which can be deprotected with HCl.

Coupling of aryl iodides bearing various functionalities including sensitive ones with alcohol (II) and subsequent silane cleavage allows the synthesis of substituted phenols under mild conditions.

Carbamic acid 2-trimethylsilylethyl ester (Teoc-NH 2 ) serves as an ammonia equivalent in the palladium-catalyzed amination of aryl bromides and aryl chlorides. Anilines with sensitive functional groups can be readily prepared using these amine derivatives.

Enhancement of the reaction rate by combining the beneficial effects of PTC and ultrasound has been explored in the present study by taking the transformation of benzamide by dehydration to give benzonitrile as a model system. It was found that there is a substantial reduction in the reaction time when ultrasound was coupled with PTC.

Using a standing wave sonochemical reactor (SWSR), the influences of parameters of ultrasonic power input, sonication time, sonication temperature and the amount of propanol (which generates the reducing radicals) were systemically investigated to ascertain and optimize the best conditions for the sonochemical reduction of Pt from its precursor hexachloroplatinic acid and then its deposition on rutile TiO(2) (platinization of rutile titania) catalysts. Catalytic activity of the prepared platinized catalysts was tested in the reaction of methyl orange degradation. The results of photocatalytic activity study in the degradation of methyl orange further demonstrate that sonochemically as-prepared Pt/TiO(2) catalysts show a pronounced increase ( approximately 2 times) in photodegradation, even with a deposition of small amounts of platinum (1.4wt.%), as compared to the unsupported or naked rutile titania. Although there are various parameters that influence the sonochemical platinization of rutile titania, the present optimization results clearly indicate that the best photocatalytic degradation of methyl orange can be obtained when the experimental conditions of the preparation were with an input power of 50W, an initial hexachloroplatinic acid volume of 70ml (which results into 1.4wt.% Pt on TiO(2)), sonication time of 90min, 0.18g of propanol and a temperature of 10 degrees C were adopted. The method of ultrasound application to prepare metal supported semiconductors has many advantages such as convenience, safety and high efficiency. Furthermore, it is hopeful that this optimization study can also be extended to the generation of similar metal supported semiconductors.

2-(Trimethylsilyl)ethanesulfonyl amide (SES-NH2) is an ammonia equivalent for the palladium-catalyzed amination of aryl bromides and aryl chlorides. Using these amine derivatives, it has been observed that anilines and anilines with sensitive functional groups can be readily prepared.

Solid Lipid Nanoparticles (SLN) containing Methotrexate (MTX), an anticancer drug for intravenous administration was formulated and characterized. The SLN dispersions with MTX, stearic acid, and soya lecithin in the ratio of 1:4:1, 1:4:1.5, and 1:4:2, sodium taurodeoxycholate and distilled water were prepared by micro emulsification solidification method. The results show that the prepared MTX-SLN particles (with MTX–Stearic acid–Soya lecithin—1:4:2) have an average size of 270 nm with 51.3% drug entrapment. The in vitro-release was attained up to 15th h. The pharmacokinetic studyreveals that the half-life and MRT of SLNs were higher than MTX solution. The life span of EAC (Ehrlich Ascite Carcinoma) bearing mice was increased when treated with MTX-SLNs (Methotrexate nanoparticles). These results clearly indicate that SLNs are a promising sustained release drug targeting system for lipophilic antitumour drugs.

In the present work hydrolysis of methyl benzoate was carried out using aqueous sodium hydroxide solution at room temperature in the presence of ultrasound since otherwise the same reaction takes place at relatively high temperature. Also, the above hydrolysis reaction was investigated at a relatively larger scale with the variation in parameters influencing the emulsification process and hence the reaction rates. It has been observed that the position of ultrasound source on the liquid–liquid interface is a crucial parameter affecting the two-phase emulsification rates. The poor bulk mixing occurring in the presence of ultrasound alone with an increase in the volume of the reaction mixture and its consequent effect on the reaction kinetics has been conclusively established. These studies have shown that the use of ultrasound with mechanical stirring can result in substantial reduction in the overall power consumption, especially for reaction systems like hydrolysis that do not require very high temperatures and pressures generated by cavitation.

Degradation of Rhodamine B, a waste water dye effluent was studied under the influence of ultrasound. In the present study, optimization of this degradation was carried out with power parameters, namely, power density (W/ml) and power intensity (W/cm2) using different ultrasonic equipments. From the studies, it has been observed that the degradation does not increase indefinitely with an increase in the power parameters, but instead, it reaches an optimum value and then decreases with a further increase in the power parameters. Also, these optima were not the same in all the ultrasonic equipments in which these studies were carried out. Difference in the type of acoustic field generated may be responsible for the different power optima observed with different ultrasonic equipments. The comparative study of the degradation of Rhodamine B using various ultrasonic equipments establishes a relationship between the area-specific parameter (intensity) and the volume-specific parameter (density) of reactivity.