Papers by Keyword: Sonochemical

Abstract: TiO₂ is a semiconductor that possesses superior chemical and physical properties, widely used in various fields. In this research, the synthesis of TiO₂ particles was carried out by the sonochemical method. Synthesis begins by mixing the precursor TiOSO₄ in H₂O with a ratio of the solvent volume (v/v) H₂O/TiOSO₄ 20-80. TiO₂ particles through sonochemically reduced for 15-75 minutes. Changes in particle diameter during the synthesis process are calculated by particle size analyzer. The results of the particle size analyzer showed that the increase in the solvent volume ratio causes the average diameter of TiO₂ particles to increase with a heterogeneous size distribution. Conversely, the increasing time on sonochemical processing causes a very significant decrease in the average particle diameter. The best parameter in the sonochemical method was the lowest solvent volume ratio, 20, and the sonochemical time process of 75 minutes generated a single anatase phase 338 nm with a spherical shape.

Abstract: Metal oxide semiconducting compounds have potential application as photocatalyst materials to decompose many types of dyes and pollutants in the water. Zn₂SnO₄ and SnO₂ are semiconducting materials that have photocatalytic properties and the properties of those two semiconducting materials in the composite form have been studied. Metal oxide compounds of Zn₂SnO₄ and SnO₂ have been prepared through sonochemical methods using ZnCl₂ and SnCl₄.5H₂O as precursors. After sonication and heat treatment at 1000 °C, we could obtain Zn₂SnO₄ and SnO₂ compound in the sample as confirmed by x-ray diffraction measurement. The volume fraction of Zn₂SnO₄ and SnO₂ phases in the sample were found to be at 60 % and 40 %, respectively. The absorption spectra revealed that the band gap of the composite materials is 3.7 eV. This material could degrade all of the methylene blue with concentration of 6.0 x 10^-6 M in 120 minutes. The band structure calculation revealed that the comparable band gap values are found for Zn₂SnO₄ and SnO₂ compounds. However, the absorption edges for those compounds are slightly different, with absorption edge at 3.2 eV for SnO₂ and 3.6 eV for Zn₂SnO₄, respectively.

Abstract: Nano particle of N-doped TiO₂ with the size of 21.42 nm was successfully created using sonochemical method. Concentration of Nitrogen (N) doping on TiO₂ was calculated using mole ratio of Urea and TTiP. Doping variations were performed by doping 5% to 9% N, and did not change the crystallite size and strain. The nanoparticle produced has a polycrystalline structure with a dominant diffraction peak (101). Doping N into TiO₂ affects the morphology of particle surface, thus tending to shrink. Results of photo catalysis on liquid samples of MB 20 ppm dye indicate that the addition of N improves the degradation ability of TiO₂, with the highest value on sample T5 of 85% and with a rate of degradation kinetics of 0.024 ppm/minute.

Abstract: The science of core-shell nanoparticles requires investigation into several physical and chemical properties of the composite nanoparticles. Unlike the conventional sol-gel or the reverse microemulsion micelle method, we presented here a non-seeded process of encapsulating superparamagnetic magnetite nanoparticles (SPMN) with silica. Physico-chemical analysis of the product was used to confirm the result of the coating procedure. Colloidal suspension of SPMN and silica nanoparticles were synthesised through coprecipitation method and modified Stöber method respectively. Afterwards, both colloidal suspensions of SPMN and silica nanoparticles were sonicated to encapsulate the SPMN with silica. Elemental mapping of the composite particles with electron spectroscopy imaging (ESI) confirmed the core-shell micrograph of the SPMN and silica. The X-ray diffraction pattern (XRD) showed the silica shell to be in amorphous form. FTIR analysis further confirmed the chemical properties of the product to be silica coated SPMN.

Abstract: Titanium dioxide nanoparticles (TiO₂) were successfully synthesized via a sonochemical-assisted process using titanium isopropoxide as the titanium sources and calcination process at 300-500 °C. The effect of sonication time and heat treatment temperature on structural and nanostructure properties of the nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM). The XRD and Raman results indicated that the crystalline of as-sonochemically synthesized TiO₂ nanoparticles corresponded to anatase phase of TiO₂ after sonication for 30 mim. The high quality crystalline anatase phase and increasing of crystalline size can be obtained after calcinations process.

Abstract: Using MgCl₂·7H₂O as the starting material and NaF as precipitating agent, nanoMgF₂ powder were prepared by sonochemical method. Morphological structure of the particle is characterized by means of XRD and SEM, TEM and Flourier Transition Infrared Spectrum. The influence factors, such as reactant concentration, reaction temperature and ultrasonic frequency were discussed. The optimum sysnthsis conditions was acquired, such as that the molar ratio of [F-] and [Mg²⁺] is 1/7.5, the reaction time 2h, the reaction temperature 80°C, the ultrasonic frequency 80kHz.

Abstract: The eucalyptus cellulose micro/nano fibrils were prepared by using high intensity ultrasonication with chemical pretreatment. The basic characteristics of cellulose micro/nano fibrils were evaluated by wide-angle X-ray diffraction instrument (WAXD) and scanning electron microscopy (SEM).

Abstract: Superparamagnetic iron oxide nanoparticles (SPION) of sizes 5 to10 nm were synthesized by the co-precipitation method. They are coated with silica nanoparticles using sonication method. The SPION was produced under the optimum pH of 10, peptized in acidic medium and redispersed in water. The silica nanoparticles were produced through the Stöbermethod. Sonochemical coating of silica nanoparticle on the SPION was successfulat a pH value lower than 5. Otherwise, at higher pH value (but lower than point zero charge (PZC)), the SPION were found to be unstable. Fast hydrolysis of triethoxyvinylsilane(TEVS) shows that silica forms its own particles without coating onto the surfaces of the SPION. Under optimized experimental condition, sonochemical method of coating silica nanoparticles onto the SPION can be considered as an alternative for effective and prompt method that rely mainly on pH of the suspension.

Abstract: Metal oxides form part of inorganic medicines called Bhasmas, which has been used in a non-allopathic medicine system practiced in India called Ayurveda. Bhasmas may be classified under the nanomedicines of ancient India. The traditional preparation methods involve time consuming and complicated preparation procedures. This paper highlights a novel ultrasound assisted technique called sonochemical synthesis of transition metal oxides in a facile, faster, inherently safer and environmentally benign (green chemistry) way which could be considered to be used for the synthesis of metal oxides such as copper oxide which form part of the copper based Ayurvedic nanomedicine called tamra bhasma, which is copper in its oxide form and used therapeutically as a source of copper. The synthesis procedure outlined here could be considered for the preparation of other types of Bhasmas also.

Abstract: Nano-sized cadmium sulfid (CdS) was synthesized successfully by a simple method using ultrasonic irradiation in the presence of polyethylene glycol (PEG 2000). X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure and morphology synthesized powder. The nanocrystaline of β-CdS was grown in face-centered cubic. The average particle size of synthesized CdS is ~25 nm. CdS suspensions have then been impregnated on cotton-based textile samples and the antibacterial activity of so-functionalized textiles has been studied with respect to E. coli. Results shows that CdS nanoparticles exhibit a strong antibacterial activity and can inhibit 97% of growth E. coli bacteria.