Sonication Intensity Research Articles

Synergistic effect of probe sonication and ionic liquid for extraction of phenolic acids from oak galls.

Phenolic acids of oak gall were extracted using ultrasonic-probe assisted extraction (UPAE) method in the presence of ionic liquid. It was compared with classical ultrasonic-bath assisted extraction (CUBAE) and conventional aqueous extraction (CAE) method, with and without the presence of ionic liquid. Remarkably, the UPAE method yielded two-fold higher extraction yield with the presence of ionic liquid, resulting 481.04mg/g for gallic acids (GA) and 2287.90mg/g for tannic acids (TA), while a decreased value of 130.36mg/g for GA and 1556.26mg/g for TA were resulted with the absence of ionic liquid. Intensification process resulted the highest yield of 497.34mg/g and 2430.48mg/g for GA and TA, respectively, extracted at temperature 50°C with sonication intensity of 8.66W/cm2 and 10% duty cycle, diluted in ionic liquid, 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [Bmim][Tf2N] at concentration of 0.10M with sample-to-solvent ratio 1:10 for 8h. Peleg's model successfully predicted the UPAE process confirming that extraction capacity is the controlling factor in extracting phenolic acids. Hence, it can be concluded that UPAE method and ionic liquid have synergistic effect as it effectively enhanced the extraction efficiency to increase the bioactive constituents yield.

Integrative Effects of Sonication and Particle Size on Biomethanation of Tropical Grass Pennisetum purpureum Using Superior Diverse Inocula Cultures

Biogas from the fast growing crop, Pennisetum purpureum, has received considerable attention in Southeast Asia since wastewater and bio-waste materials are almost completely utilized. To overcome slow hydrolysis, a rate-limiting step in anaerobic digestion of lignocellulosic biomass, superior microorganism culture, size reduction, and sonication pretreatment were co-applied. In the first experiment, the selection of anaerobic microbial culture to be used in digestion, so-called inoculum, was carried out. Specific anaerobic activities for hydrolysis and methanogenesis of sludge from different sources, a slurry digester of cattle farm (CF) and a wastewater digester of rubber latex factory (RL) were assessed. Results revealed a remarkable synergistic capability in the combined sludge, adding 10% and 49% to the overall biomethanation efficiency over the individual CF and RL sludges. In the second part, interactive effects of size reduction and sonication intensity were studied. Biomethanation efficiency as methane yield increased by 62% by size and 115% by sonication variation, but when optimally combined an additional gain of 40% was recorded. The regression model generated could estimate the energy yield increase as a function of size and sonication intensity with a satisfactory statistical precision R2 of 0.945.

Preparation of physically modified oat starch with different sonication treatments

Oat starch granules were subjected to ultrasound treatment using either a 20 kHz horn sonicator at intensities of 39, 48, 63 W/cm2 or an ultrasound bath operating at an intensity of 5 W/cm2 for 10 and 20 min. Morphological, structural and functional properties of native and sonicated samples were investigated. SEM micrographs revealed the presence of fissures and pores on the surface of starch granules treated with the horn sonicator. An obvious size reduction was also observed at the highest sonication intensity. Ultrasound treatment increased the amylose content, swelling power, solubility, Transmittance, water, and lipid holding capacity; while the gel hardness diminished after sonication. The syneresis results revealed that higher amounts of water were expelled from the sonicated starch gels during 5 days of storage as compared to the native counterpart. The onset, peak and conclusion temperatures of gelatinization increased; while, the gelatinization temperature range decreased due to sonication. A decrease in the degree of crystallinity as well as the enthalpy of gelatinization demonstrated that the crystalline structures of oat starch granules were destroyed to some extent upon sonication, while the A-type crystalline pattern remained unchanged.

Pretreatment of microalgal biomass to improve the enzymatic hydrolysis of carbohydrates by ultrasonication: Yield vs energy consumption

Microalgal biomass has been considered as a possible alternative source of carbohydrates and lipids in fermentative/reactional processes, called third generation of biofuels. Carbohydrates from microalgae are mostly composed by glucose and some pentose-derived polymers that must be hydrolyzed to be efficiently used. When enzymatic hydrolysis is applied a pretreatment is required. Sonication/ultrasonication is one of the most promising methods, and in this paper the influence of pretreatment time, sonication intensity and biomass concentration was validated, and the energy consumed in the process compared as well. Sonication intensity had the major role on the enzymatic accessibility. Pretreatment time can be used to decrease hydrolysis time. More than 90% of hydrolysis efficiency was reached when higher amplitude (sonication intensity) and pretreatment time were used. The applied energy influenced indirectly the hydrolysis process. The best saccharification/energy relation was reached when 50% of amplitude for 25 min was applied, obtaining 91% of hydrolysis yield and spending 2.4 MJ/kg of dry biomass.

Sonicated membrane separation

Membrane separation processes are currently proven technologies in many areas. The main limitation of these processes is the accumulation of matter at the membrane surface which leads to two phenomena: concentration polarization and membrane fouling. According to the publications of numerous authors permeate flux could be increased by sonication. Our work focuses on separation of real broth by sonicated ultrafiltration. The broth was originated from hydrolysis of grounded corn-cob by xylanase enzyme. The filtration was carried out in a laboratory batch stirred cell with a sonication rod sonicator. In our work the effect of the stirring, the intensity of sonication and the membrane-transducer distance was studied on the efficiency of the ultrafiltration and on the quality of separated enzymes. Results reveal that xylanase enzyme can be effectively separated from real fermentation broth by ultrafiltration and enzymes keep their activity after the process. Enzyme activity tests show that low energy sonication is not harmful to the enzyme.

Sonocrystallization—Case Studies of Salicylamide Particle Size Reduction and Isoniazid Derivative Synthesis and Crystallization

Two case studies of salicylamide particle size reduction and isoniazid derivative synthesis and crystallization realized using sonocrystallization were investigated. The size, habit, structure, thermal behavior, and spectrometric properties of sonocrystallized crystals were analyzed through scanning electron microscopy (SEM), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The effects of the operating parameters, such as sonication intensity, sonication duration, and solution concentration, on sonocrystallization were compared. The crystal size of salicylamide was reduced from 595 μm (the original size) and was efficiently manipulated to be between 40 and 80 μm. Moreover, compared with the crystal habits of unprocessed crystals and recrystallized crystals fabricated through conventional methods, the crystal habit of salicylamide could be modified to present a regular shape. The structure, thermal behavior, and spectrometric properties of sonocrystallized salicylamide were found to be in agreement with those of an unprocessed sample. For producing isoniazid derivative crystals, N′-(propan-2-ylidene)-isonicotinohydrazide was synthesized using isoniazid in acetone at 318 K. The resulting solution was then cooled by applying power ultrasound to isolate N′-(propan-2-ylidene)-isonicotinohydrazide crystals. The solid-state properties of the synthesized N′-(propan-2-ylidene)-isonicotinohydrazide was verified through PXRD, DSC, and FTIR spectroscopy. The feasibility of particle size manipulation was then demonstrated through sonocrystallization.

Highly efficient recovery of graphene oxide by froth flotation using a common surfactant

In this work, it is shown that graphene oxide (GO) sheets can be effectively recovered from aqueous solution by a simple froth flotation method. Small amounts of cetyltrimethylammonium bromide (CTAB) are added to assist with flocculating and driving the GO to the air–water interface, then ultrasonication is employed to form a foam that entrains the GO. The surfactant is essential in this process by firstly destabilising the GO dispersion through surface charge neutralisation, allowing the particles to aggregate. Furthermore, the hydrophobic component of the adsorbed surfactant molecules enhances adsorption of the GO at the air–water interface. Positioning the sonicator tip precisely at the air–water interface is crucial for foam formation by ensuring air bubbles are entrained into the sample. The nature of the foam can also be manipulated by altering the sonication intensity or by incorporating additional surfactant additives. At ideal GO:CTAB ratios, almost full removal (>99%) of the GO from an aqueous dispersion is achieved, with minimal overall change in the particle size distribution of the GO. It is shown that this process can also be used when GO is employed as an adsorbent for removing toxic metals and organic species from aqueous solution.

Ultrasonic Modified Sweet Potato Pectin Induces Apoptosis like Cell Death in Colon Cancer (HT-29) Cell Line

ABSTRACTBackground: Pectin and especially modified citrus pectin possesses anticancer activity. Hence, the current study investigated anticancer activity of ultrasonic-modified sweet potato pectin (SPP) on HT-29 cells to assess its potential as a cancer therapeutic agent. Method: The effect of ultrasonic treatment on SPP molecular weight, galacturonic acid content, degree of methoxylation, and neutral sugar was investigated. Moreover, the effect of sonicated variant on human HT-29 cell proliferation was assessed by MTT assay, cell cytotoxicity, and apoptosis by Annexin V/PI flow cytometer and caspase-3 activity was studied. Results and discussion: Sonication led up to seven-fold decrease in molecular weight. The degree of methoxylation (DM) decreased more than two-fold. Moreover, the galacturonic acid (GalA) content increased up to 92%, arabinose and galactose content increased. The SSPP inhibited cell proliferation with the IC50 values 0.5 mg/ml and 0.75 mg/ml for 400 W and 200 W SSPP, respectively. Moreover, 14.41 ± 1.64% cell cytotoxicity was elicited by 400 W SSPP and 6.83 ± 0.80% by 200 W SSPP. Both SSPPs induced apoptosis with 400 W SSPP eliciting 19.42% and 42.21% apoptosis at 0.1 and 0.5 mg/ml, while 200 W SSPP induced 13.79% and 39.50% apoptosis at 0.1 and 0.5 mg/ml, respectively. SSPP activity increased with both increased concentration and sonication intensity.

Optimization of processing parameters for the development of Ficus religiosa L. extract loaded solid lipid nanoparticles using central composite design and evaluation of antidiabetic efficacy

The aim of the present work was to optimize processing parameters for the preparation of Ficus religiosa L. extract loaded solid lipid nanoparticles (SLN) using central composite design. Optimization was carried out using four factors such as homogenization speed, homogenization time, sonication time and sonication intensity and three responses studied were particle size, polydispersity index (PDI) and zeta potential to obtain a SLN batch with lesser particle size, optimum PDI and higher zeta potential. Further, optimized batch was characterized for entrapment efficiency, surface morphology, in-vitro release and kinetics, fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder Xray diffraction (PXRD) and stability over 6 months. From the results, it was observed that increase in homogenization speed and time decreased particle size and PDI with increase in zeta potential value. Increase in sonication time up to 5 min decreased particle size and further increase had no effect on particle size. Sonication intensity had very little effect. DSC and PXRD showed reduced crystallinity of extract in SLN form. Also, the optimized batch had stability over 6 months. Further, SLN significantly reduced diabetes induced higher levels of blood glucose and increased diabetes induced lower level of plasma insulin.

Application of two-level factorial design to investigate the effect of process parameters on the sonocrystallization of sulfathiazole

In this study, cooling sonocrystallization was used to recrystallize an active pharmaceutical ingredient, sulfathiazole, using methanol as the solvent. The effects of three operating parameters-sonication intensity, sonication duration, and solution concentration-on the recrystallization were investigated by using a 2k factorial design. The solid-state properties of sulfathiazole, including the mean particle size, crystal habit, and polymorphic form, were analyzed. Analysis of variance showed that the effect of the sonication intensity, cross-interaction effect of sonication intensity/sonication duration, and cross-interaction effect of sonication intensity/solution concentration on the recrystallization were significant. The results obtained using the 2k factorial design indicated that a combination of high sonication intensity and long sonication duration is not favorable for sonocrystallization, especially at a high solution concentration. A comparison of the solid-state properties of the original and the recrystallized sulfathiazole revealed that the crystal habit of the recrystallized sulfathiazole was more regular and that its mean particle size could be reduced to approximately 10μm. Furthermore, the analytical results obtained using the PXRD, DSC, and FTIR spectroscopy indicated that the polymorphic purity of sulfathiazole improved from the original Form III/IV mixture to Form III after sonocrystallization.

Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation

Degradation of xanthan polymer in aqueous solution by ultrasonic irradiation was investigated. The effects of selected variables i.e. sonication intensity, irradiation time, concentration of xanthan gum and molar concentration of NaCl in solution were studied. Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5Wcm−2, irradiation time 120min and 0.1gL−1 xanthan in a salt-free solution. Molecular weight reduction of xanthan gum under sonication was described by an exponential decay function with higher rate constant for polymer degradation in the salt free solution. The limiting molecular weight where fragments no longer undergo scission was determined from the function. The incorporation of NaCl in xanthan solution resulted in a lower limiting molecular weight. The ultrasound-mediated degradation of aqueous xanthan polymer chain agreed with a random scission model. Side chain of xanthan polymer is proposed to be the primary site of scission action.

Extraction Optimization, Composition Analysis, and Antioxidation Evaluation of Polysaccharides from White Jelly Mushroom, Tremella fuciformis (Tremellomycetes).

We investigated the sonication-assisted extraction (SAE) conditions of Tremella fuciformis polysaccharides. Single-factor experiments showed that the optimal sonication intensity was 6 W/cm2; the other SAE conditions were further optimized using response surface experimental design. A Box-Behnken experiment exhibited that the optimal SAE conditions were temperature, 85°C; ratio of liquid to solid, 46 mL/g; and sonication time, 2 hours. The maximal polysaccharide yield (8.95 g/100 g) was obtained under the optimal extraction conditions. Polysaccharides extracted by sonication or traditional hot water extraction (TWE) were further separated and purified using DEAE-Sepharose and Sephadex G-100 column chromatography. Polysaccharide fractions (SAE-1, SAE-2, TWE-1, and TWE-2) were obtained; their molecular weights were 9.85 × 104, 6.64 × 104, 4.75 × 105, and 2.81 × 105 Da, respectively. The total sugar content of SAE-1 and SAE-2 was lower and the protein and nucleic acid contents were higher than those of TWE-1 and TWE-2. In addition, SAE-1 and SAE-2 showed stronger Fe2+-chelating activities and superoxide radical scavenging activities than TWE-1 and TWE-2. This suggests that polysaccharides extracted by sonication possess high antioxidant activities.

Safety and tolerability of silk fibroin hydrogels implanted into the mouse brain.

The increasingly use of sophisticated biomaterials to encapsulate stem cells has changed the comprehensive overview of potential strategies for repairing the nervous system. Silk fibroin (SF) meets with most of the standards of a biomaterial suitable to enhance stem cell survival and function. However, a proof-of-principle of the in vivo safety and tolerability of SF implanted into the brain tissue is needed. In this study we have examined the tissue bioresponse and brain function after implantation of SF hydrogels. We have demonstrated the benign coexistence of silk with the complex neuronal circuitry that governs sensorimotor coordination and mechanisms such as learning and memory. Our results have repercussion in the development of advances strategies using this biomaterial in regenerative neuroscience.

Performance and mechanism of low-frequency ultrasound to regenerate the biological activated carbon

Biological activated carbon (BAC) filter has been widely used as an effective water treatment but regenerations of BAC are costly. Ultrasound has been successfully applied for regeneration of activated carbon but has been less frequently applied to the regenerate the BAC. In this study, bench-scale and pilot-scale experiments were conducted to evaluate the regeneration performance and mechanism of BAC with low-frequency ultrasound. Adsorption indices, microbiological parameters, pore structure and removal efficiencies were further investigated. The results showed that low-frequency ultrasound could regenerate the BAC effectively. The regeneration effects were significantly affected by the frequency, sonication intensity, sonication time, and water temperature, but not the usage time of the BAC. The optimized conditions were identified as 40kHz of frequency, 115×10−3W/cm3 of sonication intensity, 25–30°C of water temperature and 5min of sonication time. The iodine value and methylene blue value increased from 480mg/g and 100mg/g to 680mg/g and 133mg/g respectively, the biomass decreased from 310nmolP/gC to 245nmolP/gC, while the biological activity increased from 0.03mg O2/hgC to 0.0355mg O2/hgC under the optimized condition. After three months of continuous operation, removal efficiencies of regenerated BAC were still high for the removal of organic contaminants, atrazine, and 2-MIB. Analysis of pore structure, BET surface area, and scanning electron microscopy indicated that ultrasound mainly acted on surface and macro-pores of BAC through the high-speed microjets and high-pressure microstreams resulted from the collapse of cavitation bubbles.

Effect of gold nanoparticle size on acoustic cavitation using chemical dosimetry method

When a liquid is irradiated with high intensities of ultrasound irradiation, acoustic cavitation occurs. Acoustic cavitation generates free radicals from the breakdown of water and other molecules. Cavitation can be fatal to cells and is utilized to destroy cancer tumors. The existence of particles in liquid provides nucleation sites for cavitation bubbles and leads to decrease the ultrasonic intensity threshold needed for cavitation onset. In the present investigation, the effect of gold nanoparticles with appropriate amount and size on the acoustic cavitation activity has been shown by determining hydroxyl radicals in terephthalic acid solutions containing 15, 20, 28 and 35nm gold nanoparticles sizes by using 1MHz low level ultrasound. The effect of sonication intensity in hydroxyl radical production was considered.The recorded fluorescence signal in terephthalic acid solutions containing gold nanoparticles was considerably higher than the terephthalic acid solutions without gold nanoparticles at different intensities of ultrasound irradiation. Also, the results showed that the recorded fluorescence signal intensity in terephthalic acid solution containing finer size of gold nanoparticles was lower than the terephthalic acid solutions containing larger size of gold nanoparticles. Acoustic cavitation in the presence of gold nanoparticles can be used as a way for improving therapeutic effects on the tumors.

Impact of sonication on activated sludge properties and consequences on PAH partitioning

AbstractSonication is an efficient sludge disintegration technique that can be used for reducing the excess sludge produced in water treatment. The effects of activated sludge sonication on its physicochemical properties and their consequences on the partitioning of hydrophobic polycyclic aromatic hydrocarbons (PAH) are reported. Ultrasound treatment led to an increase in dissolved and colloidal matter in the aqueous phase, with a predominance of proteins compared to the initial supernatant. This transfer of DCM was found to be directly correlated to the energy applied, and resulted in proportional transfer of PAHs from the particulate phase to the aqueous fraction. The PAH aqueous fraction, initially ranging from 0.012 g/g (pyrene) to 0.19 g/g (naphthalene), reached between 0.25–0.37 g/g when a specific energy of 40 000 kJ/kgTS0 was applied. For the raw sludge, the logarithm of the equilibrium constant varied between 3.0–4.3, depending on the hydrophobicity of the molecule, but when sonication was applied, the affinity for particles decreased significantly, resulting in a narrow distribution (log KG = 2.8–3.0 after 40 000 kJ/kgTS0 was applied). PAH partition is governed by molecule hydrophobicity (log Kow) for raw sludge and by sonication intensity for sonicated sludge.

Facile sonochemical synthesis of N,Cl-codoped TiO2: Synthesis effects, mechanism and photocatalytic performance

In this study, both nitrogen and chlorine were successfully doped into TiO2 (N,Cl-codoped TiO2) via a sonochemical method using titanium(IV) butoxide and ammonium chloride as precursors. When N,Cl-codoped TiO2 was tested on the decolorization of CI Reactive Black 5 (RB5), it was observed that the photocatalytic activity exhibited by the synthesized photocatalyst was greatly affected by the synthesis conditions. Increasing the sonication intensity or duration up to a certain point shifted the absorption onset toward a lower energy and improved the crystallinity of the synthesized photocatalyst. It was also observed that increasing the N,Cl:Ti molar ratio to 2 significantly enhanced the photocatalytic activity of N,Cl-codoped TiO2, but higher molar ratios inhibited the decolorization of RB5. A relatively low calcination temperature of 200°C was sufficient to further improve the photocatalytic activity of N,Cl-codoped TiO2. The following recommended synthesis conditions successfully yielded 96.02% RB5 decolorization under visible light irradiation for 5h: sonication amplitude of 40%, sonication duration of 3.62h, N,Cl:Ti molar ratio of 2 and calcination temperature of 200°C. The decolorization rate constant of N,Cl-codoped TiO2 (0.01min−1) was also significantly higher than that of commercially available P25 (0.0055min−1).

Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication

Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98wt% via the combined process with phosphoric acid concentration of 60wt%, cellulase dosage of 2mL (84 EGU) per 2g fiber and sonication intensity of 200W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability.

Extraction of rebaudioside-A by sonication from Stevia rebaudiana Bertoni leaf and decolorization of the extract by polymers.

Optimization of steviol glycosides extraction from Stevia rebaudiana Bertoni leaf was carried out by investigating the effects of isopropyl alcohol concentration (60%, v/v), time (6-24min), temperature (30°C) and sonic power (300-480W) on extraction of rebaudioside A from Stevia rebaudiana leaves and decolorization of the extract by polymer (Separan AP30 and Resin ADS-7). The results showed that isopropyl alcohol was suitable for the extraction of rebaudioside A from Stevia rebaudiana leaves and the yield of rebaudioside A achieved 35.61g/100g when the output power was 360W and treatment time was 18min. The sonication had influence on the particle size of stevia leaf and the color of the extracted solution. As the sonication intensity increased, the particle size decreased. The colour of differently treated stevia solutions were significantly different (P < 0.05). Separan AP30 and adsorption resin ADS-7 were performed to remove the colour impurity. The results showed that more than 65% of the coloured impurity was removed by Separan AP30 combined with Calcium oxide (CaO).

Particle Size Control and Crystal Habit Modification of Phenacetin Using Ultrasonic Crystallization

AbstractPower ultrasound is applied for cooling crystallization to control and modify the particle size and crystal habit of an active pharmaceutical ingredient, phenacetin. Operating parameters including sonication intensity and duration, solution concentration, and cooling rate are studied and compared. With respect to mean particle size, the effect of sonication intensity is most significant. In addition, the crystal habit of recrystallized phenacetin is modified substantially and shows an elliptic shape. Recrystallized phenacetin also provides an enhanced dissolution rate compared with the original sample. These results prove that ultrasonic crystallization is an efficient tool for controlling the solid‐state properties of an active pharmaceutical ingredient.