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The individual and simultaneous effects of acid and ultrasonic pretreatment on the disintegration of municipal waste activated sludge (WAS) were investigated based on chemical properties of WAS. In the combination of acid and ultrasonic pretreatment methods (ultrasonic-acid pretreatment), lowering pH accelerated and enhanced the disintegration of waste biological sludge. Therefore, the same disintegration efficiency (obtained by ultrasonic pretreatment alone) was achieved by the combined pretreatment in shorter sonication times. Optimum pretreatment conditions were ultrasonic power density of 1.0W/mL and pretreatment time of 10 min for ultrasonic pretreatment alone, and ultrasonic power density of 1.0W/mL, pretreatment time of 10min and initial sludge pH of 2.0 for the combined pretreatment. Sludge disintegration degrees were about 30% and 40% under these optimized conditions, respectively. Optimum sludge concentration was found to be 1.0% total solid (TS) content for the combined pretreatment. As a result, ultrasonic-acid pretreatment has been determined as a new and effective combined sludge pretreatment method to improve the sludge disintegration. [ABSTRACT FROM AUTHOR]

High growth rate makes Chlorella vulgaris a promising source of biomass for biogas production; however, its thick cell wall hinders the degradation process. In this study, C. vulgaris cells were subjected to ultrasonic treatment prior to anaerobic digestion for biogas production. Ultrasonic pretreatment helped release the intracellular organic substances from the cells, increased the soluble chemical oxygen demand (COD) and released proteins, facilitating further digestion of the biomass by anaerobic bacteria for enhanced biogas production. The highest methane production was obtained by pretreatment at 5,000 J mL-1 dose. The first-order equation showed a better fit in terms of R2 value as compared to the modified Gompertz equation in describing biogas production. [ABSTRACT FROM AUTHOR]

The parenchyma cellulose isolated from bagasse pith was used as an alternative resource for preparation of water-soluble cellouronic acid sodium salt (CAS). The influence of ultrasound treatment on the cellulose was investigated for obtaining CAS by regioselective oxidization using 4-acetamide-TEMPO and NaClO with NaClO2 as a primary oxidant in an aqueous buffer at pH 6.0. The yield, carboxylate content and polymerization degree (DP) of CAS were measured as a function of ultrasonic power, agitating time and cellulose consistency by an orthogonal test. The ultrasound-treated conditions were further improved by discussion of ultrasonic power, the most important factor influencing the yield and DP. An optimized CAS yield of 72.9% with DP value (DPv) of 212 was found when the ultrasonic strength is 550 W, agitating time is 3 h and cellulose consistency is 2.0%. The oxidation reactivity of cellulose was improved by ultrasonic irradiation, whereas no significant changes in crystallinity of cellulose were measured after ultrasonic treatment. Moreover, the ultrasound treatment has a greater effect on yielding CAS from parenchyma cellulose than from bagasse fibrous' one. The CAS was further characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

The research focuses on application of ultrasonic-assisted glycosylation in food protein modification. Biological activities and in vitro digestion characteristics of the glycosylated α-lactalbumin (UMGLA) and α-lactalbumin (UMLA) prepared by ultrasonic pretreatment and microwave heating at 85 °C for 2 h were investigated mainly through the browning degree, free amino group, reducing sugar and surface hydrophobicity, in vitro digestibility and degree of hydrolysis, total antioxidant capacity, α-glucosidase inhibitory activity, xanthine oxidase inhibitory activity determination methods. The results showed that ultrasonic pretreatment could effectively promote the occurrence of glycosylation reaction, reduce in vitro digestibility and degree of hydrolysis of glycosylated α-lactalbumin and enhance biological activities of glycosylated α-lactalbumin digestive products. Furthermore, after 60 min of ultrasound treatment, the total antioxidant capacity and α-glucosidase inhibitory activity of glycosylated α-lactalbumin digested products were increased by 76.52 ± 0.02% and 12.42 ± 0.04%, respectively, compared with α-lactalbumin without ultrasound treatment. In conclusion, ultrasonic-assisted glycosylation had positive effects on improving the biological activities of in vitro digestion product of α-lactalbumin. It provides a theoretical basis for ultrasonic-assisted glycosylation in the modification field of food proteins. [Display omitted] Ultrasonic pretreatment can promote the glycosylation of α-LA and xylose Digestibility and degree of hydrolysis of glycosylated α-LA reduced by ultrasound. Ultrasound enhanced biological activities of glycosylated α-LA digested products [ABSTRACT FROM AUTHOR]

Highlights: [•] Ultrasonic pretreatment significantly changes the structure of the rice husk. [•] The pretreated rice husks have higher conversion and bio-oil yield. [•] Ultrasonic pretreatment changes the chemical composition of the bio-oil. [Copyright &y& Elsevier]

Highlights: [•] BMP of whole and soluble fraction of pretreated (alkali+ultrasonication) sludge. [•] Decrease of CH4 conversion of soluble fraction with solubilization increase. [•] In case of severe pretreatment (pH 13+Ul 60min), only 61% was converted to CH4. [•] Soluble but non-biodegradable portion at (pH 13+Ul 60min)=25.8%. [•] Increased solubilization does not always result in enhanced AD efficiency. [Copyright &y& Elsevier]

Highlights: [•] Ultrasonic pretreatment lipase-catalyzed synthesis of 4-methoxy cinnamoyl glycerol (4MCG) was studied. [•] The enzymatic method using ultrasonic pretreatment significantly improved overall esterification reaction rate and monoester (4MCG) yield. [•] The ultrasonic pretreatment process did not damage the lipase activity. [Copyright &y& Elsevier]

Highlights: [•] Main ultrasound pretreatment process parameters were optimized. [•] The effect of external pressure was investigated for the first time. [•] At a given power, an optimum pressure was found regardless of specific energy input. [•] High US power, adiabatic mode, and optimum pressure was the best combination. [•] The process of sludge particle size reduction was much faster than COD extraction. [ABSTRACT FROM AUTHOR]

Vegetable waste was used as the fuel of a two-chamber microbial fuel cell (MFC) for simultaneous power recovery and waste degradation. Effects of ultrasonic pretreatment, organic loadings, anolyte pH adjustment on the MFC performance were investigated. Results showed that higher power generation and organic compounds removal efficiency were achieved in the MFCs with the vegetable waste pretreated with ultrasonication at >1.0W/mL compared to the un-pretreated control. A maximum voltage of 491 mV (1000 external resistor), power density of 10.19 W/m³ and 7-d TCOD removal rate of 62.5% were attained for the ultrasonic pretreated samples, while the corresponding parts for the un-pretreated control were 430 mV, 5.96 W/m³ and 35.1%, respectively. For stable power generation and effective removal of the waste in the MFC system, the raw waste required a certain dilution and the anode solution should be adjusted to improve system buffering capacity. [ABSTRACT FROM AUTHOR]

Abstract: This study is focused on the enzymatic esterification of phytosterols with different acyl donors to produce the corresponding phytosterol esters catalyzed by Canadia sp. 99-125 lipase under ultrasound irradiation. An ultrasonic frequency of 35kHz, power of 200W and time of 1h was determined to guarantee satisfactory degree of esterification and lipase activity. The influence of temperature, substrates concentration and molar ratio was investigated subsequently. The optimum production was achieved in isooctane system at 60°C with phytosterol concentration of 150μmol/mL and phytosterol to fatty acid molar ratio of 1:1.5, resulting in a phytosterol esters conversion of above 85.7% in short reaction time (8h). Phytosterols esters could also be converted in high yields to the corresponding long-chain acyl esters via transesterification with triacylglycerols (above 90.3%) under ultrasound irradiation. In optimum conditions, the overall esterification reaction rate using the ultrasonic pretreatment process was above 2-fold than that of mechanical stirring process without damage the lipase activity. [Copyright &y& Elsevier]

Abstract: In this study ultrasonic (US) pretreatment was investigated with the aim of improving the anaerobic digestion of sunflower oil cake (SuOC), the solid waste derived from the extraction process of sunflower oil. Five ultrasonic pretreatment assays were conducted at specific energy (SE) and sonication times in a range from 24,000kJ/kg TS and 16.6min (assay 1: US1) to 597,600kJ/kg TS and 331.2min (assay 5: US5), respectively, all operating at a constant sonication frequency (20kHz) and ultrasonic power (120W). As regards ultrasonic pretreatment, the working conditions of the first assay (US1) using samples of SuOC at 2% (w/v) showed to be the most appropriate in terms of both lignin and hemicellulose degradation (57.7% and 66.7%, respectively) and cellulose increase (54% increase with respect to its initial concentration). The percentage of COD solubilization increased from only 14% to 21% when SE was 25 times higher. Results obtained in batch anaerobic digestion experiments (biochemical methane potential – BMP – tests) conducted at 35°C of the solid and liquid fractions released from the different ultrasonic conditions tested, indicated that for the first experiment (US1) the average ultimate methane yield obtained was 53.8% higher than that achieved for untreated SuOC. Finally, the kinetic constants of the anaerobic digestion of the solid and liquid fractions released after the ultrasonic pretreatment were virtually independent of the operation conditions assayed. [Copyright &y& Elsevier]

Abstract: The effect of temperature on the hydrolysis and acidification of ultrasonic-pretreated waste activated sludge (WAS) under alkaline conditions was investigated in this study. The experiment temperatures were set at 10, 20, 37, and 55°C. Experimental results showed that the hydrolysis of ultrasonic-pretreated WAS under alkaline conditions increased significantly with temperature from 10 to 55°C, while the volatile fatty acid (VFA) accumulation was not augmented as temperature increased. Among the four temperatures tested, 37°C was the point with the highest VFA accumulation after 72h fermentation. VFA accumulation decreased markedly at 55°C compared to 37°C. Mechanism investigation revealed that among all the temperatures tested, 37°C was the temperature at which consumptions of WAS protein and carbohydrate, activities of key enzymes related to VFA formation and ratio of Bacteria to Archaea all reached the maximum. Due to activities of related microorganisms inhibited by higher temperature (55°C), VFA accumulation decreased at 55°C. [Copyright &y& Elsevier]

Abstract: The application of ultrasound for treating rice hull used as the fermentation substrate for xylooligosaccharides production was investigated. Aspergillus japonicus CY6-1 was selected to produce cellulolytic and xylanolytic enzymes from untreated rice hull (RH) and rice hull treated with ultrasound (USRH-M). The hemicellulose yield was increased to 1.4-fold with ultrasound, and treatment time was greatly shortened from 24h to 1.5h at 80°C and 300W/28kHz. The morphology of RH from various pretreatments was observed with field emission scanning electron microscope (FESEM), revealing the surface structure of USRH-M smoother than that of RH. USRH-M was much easier to be utilized by fungi, to extend the stability of enzyme activity and to increase activities of CMCase, β-glucosidase, and xylanase compared with those of untreated RH. The final fermentative products were xylotetraose, xylohexaose, and higher molecular weight xylooligosaccharides, achieving xylohexaose yield for USRH-M 80% higher than that for RH group. [Copyright &y& Elsevier]

ABSTRACT In this study, the effect of osmotic pretreatments (with or without ultrasound) in combination with hot-air or microwave-assisted hot-air drying methods on the texture, microstructure, color and water activity of dried cranberries were investigated. Osmotic pretreatments were done in a ternary solution (sucrose-NaCl-water) under three different temperatures: 30, 40 and 50C. The concentrations of osmotic solutions were 40, 50 and 60% of sucrose and 0, 4 and 8% of NaCl. Also, the influence of the two levels of frequency of ultrasound (35 and 130 kHz) on the quality properties was investigated. Our results showed lower hardness and water activity ( aw) when higher temperature, sucrose and salt were used. Applying ultrasound reduced the hardness and aw of samples. With increasing the frequency of ultrasound, hardness ( N) and aw were decreased. Microwave energy reduced drying time and can modify the structure, texture strength and color of the final product. PRACTICAL APPLICATIONS Cranberry contains high levels of phytochemicals, which have health-promoting properties. Some of these phytochemicals, such as anthocyanins, act as an antioxidant, reducing the oxidative damage to cells, which can lead to cancer, heart disease and other degenerative diseases. Recently, cranberry products have been used with the hope of preventing or treating urinary tract infections or Helicobacter pylori infections, which can lead to stomach ulcers, or to prevent dental plaque. Osmotic dehydration is a suitable way to produce shelf-stable products or partially dehydrated foods without enduring heat damage. The osmotically dehydrated cranberries can be consumed as healthy snacks or can be suited to a wide range of food formulations, including jams or sweets. [ABSTRACT FROM AUTHOR]

Abstract: This study demonstrates for the first time that the enzymatic hydrolysis of cellulose is drastically enhanced following ultrasonic pretreatment of lignocellulosic material in ionic liquids (ILs) when compared to conventional thermal pretreatment. Five types of ILs, 1-buthyl-3-methylimidazolium chloride (BmimCl), 1-allyl-3-methylimidazolium chloride (AmimCl), 1-ethyl-3-methylimidazolium chloride (EmimCl), 1-ethyl-3-methylimidazolium diethyl phosphate (EmimDep), and 1-ethyl-3-methylimidazolium acetate (EmimOAc) were tested. Cellulose saccharification ratio was about 20% for kenaf powders pretreated in BmimCl, AmimCl, EmimCl, and EmimDep by conventional heating at 110°C for 120min. Conversely, 60–95% of cellulose was hydrolyzed to glucose, subsequent to ultrasonic pretreatment in the same ILs for 120min at 25°C. The cellulose saccharification ratio of kenaf powder in EmimOAc was 86% after only 15min of the ultrasonic pretreatment at 25°C, compared to only 47% in that case of thermal pretreatment in the IL. [Copyright &y& Elsevier]

This study highlights the removal of Congo red from its aqueous solution using Strychnos potatorum seed powder (SPSP), an Indian seed, used from ancient times for the treatment of turbid water. Surface activation of the adsorbent was carried out using ultra sonication techniques. Comparative studies on the uptake of the dye by both unsonicated and sonicated adsorbents were carried out. Experiments were conducted at various initial concentrations of dye and the influence of pH, biomass, temperature and contact time on the uptake of dye by SPSP was studied. High removal efficiency was observed at relatively low concentration of the dye. The optimum pH and temperature for the adsorption process was 6 and 28°C, respectively. The data obtained were found to follow the pseudo first order kinetics and the Boyd's film-diffusion model. The thermodynamic studies showed that the adsorbent was more suitable for the removal of dyes. [ABSTRACT FROM PUBLISHER]

Abstract: Microbial fuel cell (MFC) could be an efficient sludge treatment unit in regard of rates and extents of total chemical oxygen demand (TCOD) removal, particularly when ultrasound was applied to pretreat the sludge. This study characterized the organic matter in sludge before and after MFC treatment, with or without ultrasound as a pretreatment stage. The 5-d MFC tests with electric load significantly enhanced TCOD removal rate from 11.3% to 19.2% for raw sludge and from 25% to 57% for sludge pretreated with >0.6Wml−1 ultrasound, using conventional anaerobic digestion test (without electric load) as control. The aromatic proteins, soluble microbial byproduct-like fluorescent compounds and carboxylic components, aliphatic components (C–H related), hydrocarbon and carbohydrate materials were identified to be principally released by ultrasound pretreatment and the fuels in the present MFC study. [ABSTRACT FROM AUTHOR]

Both ultrasonic and alkaline pretreatment of excess sewage sludge were investigated to enhance organic degradation and electricity generation from sludge by the subsequent microbial fuel cell (MFC). The ultrasonic pretreatment showed that the degree of sludge disintegration was directly related to the energy input, ultrasonic density and duration. Alkaline pretreatment demonstrated that more soluble organic matters were released from the sludge with more NaOH dose and longer reaction time, and the degree of sludge disintegration within 30 min accounted for 45-76% of that for 24 h. When ultrasonic and alkaline pretreatment were combined, the released chemical oxygen demand (COD) was higher than those with ultrasonic or alkaline pretreatment alone. Ultrasonic and alkaline (pH = 11) pretreatment could enhance electricity generation from sludge by the subsequent MFC, resulting in more degradation of total COD (TCOD) and volatile solids (VS). Slight change in power output from the MFC was observed due to the higher soluble chemical oxygen demand (SCOD) in the pretreated sludge. By using the combined ultrasonic and alkaline pretreatment of sludge, the removal efficiencies of TCOD and VS were increased from 27.1% to 61.0% and 35.2% to 62.9% in comparison with raw sludge, respectively, and the power output in MFC was slightly increased from 10.3W/m3 to 12.5W/m³. [ABSTRACT FROM AUTHOR]

Abstract: The individual effects of alkaline (pH 8-13) and ultrasonic (3750–45,000kJ/kg TS) pretreatments on the disintegration of sewage sludge were separately tested, and then the effect of combining these two methods at different intensity levels was investigated using response surface methodology (RSM). In the combined pretreatment, ultrasonic treatment was applied to the alkali-pretreated sludge. While the solubilization (SCOD/TCOD) increase was limited to 50% in individual pretreatments, it reached 70% in combined pretreatment, and the results clearly showed that preconditioning of sludge at high pH levels played a crucial role in enhancing the disintegration efficiency of the subsequent ultrasonic pretreatment. By applying regression analysis, the disintegration degree (DD) was fitted based on the actual value to a second order polynomial equation: Y =−172.44+29.82X 1 +5.30×10−3 X 2 −7.53×10−5 X 1 X 2 −1.10X 1 2 −1.043×10−7 X 2 2, where X 1, X 2, and Y are pH, specific energy input (kJ/kg TS), and DD, respectively. In a 2D contour plot describing the tendency of DD with respect to pH and specific energy input, it was clear that DD increased as pH increased, but it seemed that DD decreased when the specific energy input exceeded about 20,000kJ/kg TS. This phenomenon tells us that there exists a certain point where additional energy input is ineffective in achieving further disintegration. A synergetic disintegration effect was also found in the combined pretreatment, with lower specific energy input in ultrasonic pretreatment yielding higher synergetic effect. Finally, in order to see the combined pretreatment effect in continuous operation, the sludge pretreated with low intensity alkaline (pH 9)/ultrasonic (7500kJ/kg TS) treatment was fed to a 3 L of anaerobic sequencing batch reactor after 70 days of control operation. CH4 production yield significantly increased from 81.9±4.5mL CH4/g CODadded to 127.3±5.0mL CH4/g CODadded by pretreatment, and this enhanced performance was closely related to the solubilization increase of the sludge by pretreatment. However, enhanced anaerobic digestion resulted in 20% higher soluble N concentration in the reactor, which would be an additional burden in the subsequent nitrogen removal system. [Copyright &y& Elsevier]

Abstract: This research focused on the use of high-power ultrasound prior to soy protein extraction to simultaneously enhance protein and sugar release in the extract. Defatted soy flakes dispersed in water were sonicated for 15, 30, 60 and 120s using a bench-scale ultrasound unit. The ultrasonic amplitudes used were: 0, 21, 42, 63 and 84μmpp (peak-to-peak). The respective power densities were 0.30, 0.87, 1.53 and 2.56W/ml. Scanning electron micrographs of sonicated samples showed the structural disruption of soy flakes. The particle size decreased nearly 10-fold following ultrasonic treatment at high amplitudes. Sonication at high amplitude for 120s gave the highest increase in total sugar released (50%) and protein yield (46%) when compared with non-sonicated samples (control). Ultrasonic pretreatment was also carried out with and without cooling for temperature moderation. The heat generated during sonication had no significant effect on protein and sugar release from defatted soy flakes. The use of ultrasound can significantly improve protein yield and reduce the overall cost of producing soy protein from flakes. [Copyright &y& Elsevier]

It is proposed that anaerobic treatment of municipal wastewater in temperate climates is attainable through the fortification of wastewater with primary sewage sludge to enhance the chemical oxygen demand (COD). Three bench-scale up-flow anaerobic sludge blanket (UASB) bioreactors (0.5 L) were operated to provide a preliminary verification of this approach. Mass and energy balances were modelled using the GPS-X (COST model, population equivalent of 118,500) to determine the energy balance of the primary sludge wastewater fortification process flowsheet in comparison with conventional aerobic secondary treatment with activated sludge. The addition of 5% primary sludge by volume to crude wastewater pretreated with ultrasound resulted in an increase in total COD from 536 mg L-1 to 2300 mg L-1. A COD removal of 86% ± 8% and methane production of 400 mL L-1 d-1 were achieved in the reactor that was supplied with this primary sludge fortified wastewater. In comparison a COD reduction of 77% ± 8% and 40 mL L-1 d-1 of methane were observed in the reactor which was supplied with crude wastewater only, and a 79% ± 8% COD removal and 156 mL L-1 d-1 of methane were observed in UASB2, which was supplied with crude wastewater pretreated with ultrasound. The modelled energy balance for the fortified wastewater treatment process flowsheet was -305 kWh d-1 compared with -937 kWh d-1 in the aerobic flowsheet, corresponding to an energy saving of 67%. [ABSTRACT FROM AUTHOR]

Abstract: A series of nano-gold catalysts supported on binary oxides MO x –CeO2 (atomic ratio M/Ce=1:1, M=Mn, Fe, Co, Ni) are prepared by deposition–precipitation (DP). An innovative and rather convenient ultrasonic pretreatment of the support is employed for Au/MnO x –CeO2 preparation. It is found that for preferential CO oxidation Au/MnO x –CeO2 is more active than Au/CeO2. Ultrasonic pretreatment of MnO x –CeO2 further promotes the performance of Au/MnO x –CeO2, with CO conversion increased by 24 % at 120°C. Meanwhile, the selectivity of oxygen to CO2 is promoted in the whole temperature range, especially in 80–120°C, the selectivity is increased by 15–21%. HR-TEM and XRD results indicate that ultrasonic pretreatment is favorable to the formation of much smaller gold nanoparticles (<5nm). The characterization of XPS, UV–vis DRS, H2-TPR and CO-TPR confirms that the strong interaction between Au and the support effectively inhibits the dissociation and oxidation of H2 over the ultrasonically pretreated catalyst Au/MnO x –CeO2, making it highly selective to CO oxidation. [Copyright &y& Elsevier]

• Ultrasonic dramatically enhanced lignans accumulation in flax sprouts. • SDG was the main component of flax lignans after germination. • PLR was the key gene for lignan biosynthesis in flax sprouts. • Fiber flax sprout was more sensitive to ultrasound pretreatment. • 2–4 min, 2 kW was the best condition of ultrasonic pretreatment for flax sprouts. This study evaluated different ultrasonic treatments for lignan biosynthesis in two varieties of flax sprouts. Results showed that lignans in flax sprouts significantly raised with ultrasonic pretreatment. Secoisolariciresinol diglucoside dramatically increased by about 6-fold at the flax sprouts. Ultrasonic pretreatment could also affect the accumulation of caffeic acid and p -coumaric acid in flax sprouts. Moreover, it is suggested that fiber flax sprout was more sensitive to ultrasonic pretreatment. The expression levels of genes involved in the biosynthesis of lignan were analyzed and the results could partly explain the accumulation of these compounds. The contents of secoisolariciresinol diglucoside were clustered with ferulic acid, which indicated that the accumulation of ferulic acid might be the key factor during flax sprout maturation for lignan accumulation. Present study could be useful guidance for ultrasonic pretreatment in the promotion of lignan accumulation and the fortification of nutritional values in flax sprouts as a functional vegetable. [ABSTRACT FROM AUTHOR]

• H 2 SO 4 and ultrasonic-H 2 SO 4 pretreatments raised biohythane yield by 13.6 and 11.5%. • Ultrasonic-H 2 SO 4 and H 2 SO 4 pretreatments reduced the digestion time by 15.8%. • Ultrasonic-H 2 SO 4 enriched soluble chemical oxygen demand and free amino nitrogen. • The higher the COD/SO 4 2- ratio, the more bio-CH 4 yield production. • The lower the COD/SO 4 2- ratio, the more bio-H 2 yield and sulfate removal. Tofu processing residues (TPR) have received more attention as a source of bioenergy. However, their low solubility has hindered biohythane generation. Consequently, the ultrasonic and H 2 SO 4 pretreatments were combined and compared for the first time to improve the hydrolysis of organic matter and carbohydrate and increase free amino nitrogen generation from TPR. Besides, the impact of pretreatments on biohythane generation was investigated. Under the optimal conditions of 7.54% substrate level, 8% H 2 SO 4 concentration, 80 °C and 50 min, the coincident ultrasonic-H 2 SO 4 pretreatment enriched the contents of soluble chemical oxygen demand, reducing sugar, and free amino nitrogen to 49675 mg/L, 26 g/L, and 1721 mg/L, respectively, greater than individual pretreatments. Also, Biohythane yield increased by 4.24–13.61% over control (389.42 ± 23.7 ml/g-VS fed). Furthermore, hydrogen yield at 42.5 ± 2.08 and 28.1 ± 1.07 ml/g-VS fed and sulfate removal efficiency at 93 and 92% were significantly improved with ultrasonic-H 2 SO 4 and H 2 SO 4 pretreatments, respectively, indicating acidogenic and sulfidogenic activity enhancement. [ABSTRACT FROM AUTHOR]

The potential of ultrasonic pretreatment enhancing selective surface dissolution to improve the floatability of spodumene with different size fractions was verified and investigated. For coarse particles of −0.15 + 0.0385 mm, compared with traditional pretreatment methods, ultrasonic pretreatment could optimize the physicochemical properties of the surface, markedly increased the amount of NaOL adsorbed on the mineral surface, and improved the floatability of the spodumene. For fine particles of −0.0385 mm, both pretreatment methods (Ultrasonic and Traditional) could greatly increase the flotation recovery, but ultrasonic pretreatment had no obvious advantage compared with traditional method. ICP combined with XPS analysis were conducted to investigate the dissolution mechanism of spodumene surface in different pretreatment system. Si species on the surface of coarse particles were easily dissolved into the solution under the effect of ultrasound, which increases the relative content of Al and Li species on the surface. This was conducive to the adsorption of the collectors on the surface. However, the selective dissolution of the fine particle surface was weakened by excessive energy intake in the ultrasonic system, which neutralized the advantage brought by the large amount of dissolution, making the results obtained by the two preprocessing methods the same. [ABSTRACT FROM AUTHOR]

Abstract: Ultrasonic pretreatment of excess sludge can improve its aerobic digestibility, leading to enhanced sludge reduction. In order to understand the mechanisms of this improvement, sludge flocs were divided into four layers, i.e. (1) slime, (2) loosely bound extracellular polymeric substances (LB-EPS), (3) tightly bound EPS (TB-EPS) and (4) pellet. Extracellular proteins, polysaccharides and five types of hydrolytic enzymes (protease, α-amylase, α-glucosidase, alkaline-phosphatase and acid-phosphatase) from sludge flocs were investigated to determine their influence on sludge aerobic digestion after ultrasonic pretreatment. Results suggested that most of the extracellular enzymes (except α-amylase) were present in pellet and TB-EPS layers, with minor quantities detected in LB-EPS and slime layers, and almost none detected in bulk solution. As for α-amylase in sludge flocs, most of it (52.6%) was also mainly bound with pellet; however, the rest of it was dispersed nearly uniformly throughout the sludge flocs. Ultrasonic pretreatment enhances enzymatic activities and promotes the shifts of extracellular proteins, polysaccharides and enzymes from inner layers of sludge flocs, i.e., pellet and TB-EPS, to outer layers, i.e., slime, to increase the contact and interaction among extracellular proteins, polysaccharides and enzymes that were originally embedded in the sludge flocs, resulting in improved efficiency in aerobic digestion. The optimum ultrasonic pretreatment conditions had a lasting time of 10min and density of 3kWL−1 at the frequency of 20kHz. With the optimum ultrasonic pretreatment, the sludge reduction for TSS in aerobic digestion was 42.7% in which the part of 11.8% was removed by the ultrasonic pretreatment, compared with 20.9% for control, after an aerobic digestion time of 10.5d. [Copyright &y& Elsevier]

Sewage sludge is a cost-effective media for the production of Bacillus thuringiensis (Bt) based biopesticides. To enhance the entomotoxicity of the fermentation broth, pretreatments of sewage sludge by alkali and ultrasonic were applied in this study. Effects of alkaline and ultrasonic pretreatments on the soluble COD (SCOD) and total COD (TCOD) were evaluated by altering the alkali addition dose and the ultrasonic specific energy. Suitable pretreatment conditions were optimized with 5 g l−1 sodium hydroxide (NaOH) for alkaline treatment and 1.2 × 105 kJ kg−1 of total solid for ultrasonic treatment. Fermentations of raw and pretreated sludge for biopesticides were carried out in a bench scale fermentor. Results revealed that both pretreatments were effective for Bt growth and metabolism. Higher viable cells (VC) and viable spores (VS) counts, δ-endotoxin yields and entomotoxicity were achieved in the pretreated sludge. The enhancement was attributed to more available nutrients and better oxygen transfer. Moreover, ultrasonic pretreated sludge was superior to alkaline pretreated sludge for δ-endotoxin production and entomotoxicity owing to its higher soluble C/N ratio and finer particles. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the effects of ultrasonic pretreatment and various treatments on the aerobic degradation of four phthalic acid esters (PAEs) such as diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP) and di-(2-ethyl hexyl)phthalate (DEHP) in sludge. The effect on PAE degradation of treating sludge with a 20min sonication period at a power level of 0.1Wml−1 was evaluated. The degradation rates of the four PAEs were DBP>BBP>DEP>DEHP. Degradation rate constants (k 1) and half-lives (t 1/2) for the four PAEs (50mgkg−1) ranged from 0.182 to 0.379 day−1 and 1.8 to 3.8 days, respectively. The optimal pH for PAE degradation in sludge was 7.0 at 30°C. PAE degradation was enhanced by the addition of yeast extract, brij 30 or brij 35 and inhibited by the addition of hydrogen peroxide. Our results show that a combination of ultrasonic pretreatment and biodegradation can effectively remove PAE from sludge. [Copyright &y& Elsevier]

Municipal wastewater sludge, particularly waste activated sludge (WAS), is more difficult to digest than primary solids due to a rate-limiting cell lysis step. The cell wall and the membrane of prokaryotes are composed of complex organic materials such as peptidoglycan, teichoic acids, and complex polysaccharides, which are not readily biodegradable. Physical pretreatment, particularly ultrasonics, is emerging as a popular method for WAS disintegration. The exposure of the microbial cells to ultrasound energy ruptures the cell wall and membrane and releases the intracellular organics in the bulk solution, which enhances the overall digestibility. This review article summarizes the major findings of ultrasonic application in WAS disintegration, and elucidates the impacts of sonic treatment on both aerobic and anaerobic digestion. This review also touches on some basics of ultrasonics, different methods of quantifying ultrasonic efficacy, and some engineering aspects of ultrasonics as applied to biological sludge disintegration. The review aims to advance the understanding of ultrasound sludge disintegration and outlines the future research direction. There is general agreement that ultrasonic density is more important than sonication time for efficient sludge disintegration. Published studies showed as much as 40% improvement in solubilization of WAS following ultrasonic pretreatment. Based on kinetic models, ultrasonic disintegration was impacted in the order: sludge pH > sludge concentration > ultrasonic intensity > ultrasonic density. Both laboratory and full-scale studies showed that the integration of an ultrasonic system to the anaerobic digester improved the anaerobic digestibility significantly. [ABSTRACT FROM AUTHOR]

Abstract: Nano-crystalline diamond (NCD) films on silicon were synthesized at a low temperature of 450–550 °C and a low pressure of ∼7 Torr by a hot filament chemical vapor deposition (HFCVD) in a mixture of CH4 and H2. The synthesis process included pretreatment, nucleation, growth and in situ annealing steps. The Si wafers were ultrasonically pretreated in a suspension of acetone and diamond powder (20–40 μm in diameter). It was found that the key parameter to obtain smooth NCD films by conventional HFCVD without Ar was the high nucleation density (ND). Optimal ultrasonic pretreatment with coarser diamond powder and nucleation at 2.5% CH4 greatly increased the ND to about 1.5×1011 cm−2. The NCD films with average grain sizes in the range of 40–70 nm, thickness less than 500 nm and surface roughness of ∼19 nm were grown at 1.5% CH4, 550 °C and 7 Torr, their optical transmittance in the near infrared (NIR) range was as high as 85%. [Copyright &y& Elsevier]

Supercritical fluid extraction (SFE) using CO 2 was performed on soil material artificially contaminated with diesel fuel. Raising the temperature from 313 K to 343 K caused the recovery efficiency to increase from 52 to 76%. Pressure and CO 2 flow rate were found to be less important. As expected, increasing extraction time resulted in higher recoveries. Ultrasonic pretreatment of the soil material was found to be very effective, possibly due to disrupting the strong interaction bonding between soil matrix and contamination. [ABSTRACT FROM AUTHOR]

Arguably the oldest method human use to extent the shelf life of food, drying inevitably inherits undesirable physiochemical changes due mainly to how the moisture in food is removed. The present study investigated how ultrasonic pretreatment (UP) affected the color, antioxidant capacity, and rehydration kinetics of lotus seeds (LSs) subjected to subsequent microwave vacuum drying (MVD). Samples of LSs were subjected to UP at intensities of 6.08, 8.39, and 10.84 W/cm2 for 10 min, followed by MVD. UP at the highest intensity (10.84 W/cm2) changed color by increasing L * and b * but decreasing a * and also improved antioxidant activities by enhancing hydroxyl and superoxide anion radical-scavenging activities of microwave vacuum dried LSs. These changes were correlated with the increasing of gallic acid by 17.57%, chlorogenic acid by 106.73%, caffeic acid by 47.80%, rutin by 105.07%, but decreasing the content of p -hydroxybenzoic acid by 15.47% as compared to Fresh-MVD (fresh LSs dried by MVD). Under higher ultrasonic intensity, more notches and grooves appeared on surface of dried LSs which were observed by field emission scanning electron microscopy, which increased rehydration rate. Therefore, ultrasonic technique can be employed as a pretreatment method before the drying operation in order to retain the quality of the dried products. • The effect of ultrasonic pretreatment (UP) on quality of dried lotus seeds (LSs) was studied. • Increase in L* and b * but decrease in a* value resulted in LSs after UP. • Antioxidant activities of LSs peaked at the highest ultrasonic intensity. • Antioxidant activities changed in LSs after UP was attributed to phenolic content. [ABSTRACT FROM AUTHOR]

• Ultrasonic pretreatment can break the extracellular polymeric substances and cell wall structure as well as role of free radical. • Inorganic salt adsorbing in the surface of hydrochar affected on the real hydrochar properties. • Disruption extracellular polymeric substance structure and enhancing hydrolysis were key steps to hydrothermal carbonization of sewage sludge. In order to analyze the influence of disruption extracellular polymeric substances (EPS) and cell wall on the hydrothermal carbonization (HTC) of sewage sludge (SS), ultrasonic pretreatment was selected to dispose. According to solid phase and aqueous phase analysis results, it indicated that ultrasonic pretreatment can effectively break the EPS and cell wall structure, resulting in hydrolysis, dehydration and decarboxylation enhancing during HTC. The role of free radical increased elemental content in hydrochar. NaCl, which promoted hydrolysis, dehydration and decarboxylation, affected on the "real" hydrochar properties for it can be adsorbed in the surface of hydrochar. Disruption EPS structure and enhancing hydrolysis were key steps to HTC of SS, which would influence solid and liquid phase properties. The results would give more help to understand HTC process and dispose to other organic waste. [Display omitted] [ABSTRACT FROM AUTHOR]

Cannabis ruderalis straw (CRS) was anaerobically co-digested with blackwater to produce biomethane. Methane production was enhanced when the CRS was pretreated ultrasonically before anaerobic digestion with blackwater (BW). The modified Gompertz model (MGM) and a logistic function model (LFM) were employed to determine the kinetics of methane-rich bioenergy production from the co-digestion of CRS-BW. A maximum methane yield of 399 ml/gVS was obtained from the co-digestion of CRS-BW when the CRS was pretreated with ultrasound at 100 W for 30 min. The ultrasonic pretreatment broke down the CRS structure and enlarged the accessible surface area, increasing the CRS solubilization and enhancing the methane yield to nearly 1.8 times the yield of the non-ultrasonicated CRS control. Model simulation indicated that the MGM predicted the production of methane more accurately than the LFM, as evidenced by the high correlation coefficient and the high Pearson's correlation between predicted and actual values. This study demonstrated the feasibility of anaerobic co-digestion of CRS and BW, providing a sound basis for cost-efficient and stabilized bioenergy recovery from biomass. [Display omitted] [ABSTRACT FROM AUTHOR]

Glycated conjugates were prepared by heating aqueous dispersions of soy protein isolate (SPI) and maltodextrin (MD) after ultrasonic treatment (138 W/cm2, 20 kHz) for 5, 15, and 25 min. The effect of the ultrasonic pretreatment on the structure, physicochemical characteristics, and acid-induced gelation properties of the resulting SPI–MD conjugates was investigated. The analyses of free amino groups, degree of graft, intermediates, and browning intensity confirmed the formation of SPI–MD conjugates. The ultrasonic treatment promoted the glycation reaction, which led to the increase in the β-type ordered secondary structure and less compact tertiary conformation of conjugates. The ultrasonic treatment for 5 min increased the isoelectric point, surface hydrophobicity (H 0), free sulfhydryl (-SH) groups, and particle size of the conjugates. These changes in the structural and physicochemical properties of the conjugates affected their acid-induced gelation. Glucono-δ-lactone was used to form acid gels at 25 °C. Although the glycation with MD deteriorated the acid-induced gelation properties of SPI, the 5 min ultrasonic conjugates formed gels faster than the untreated conjugate, and their gels exhibited higher storage modulus (G′), gel strength, and water holding capacity (WHC), as well as denser microstructure, than the untreated conjugate gels. However, prolonged ultrasonic treatment (15 or 25 min) weakened the gelation properties of the conjugates by promoting the glycation reaction and reducing the H 0. Thus, an optimum ultrasonic pretreatment can be used to modify the structure of soy protein glycation conjugates to control their gelation properties. Image 1 • Glycated conjugates of soy protein isolate (SPI) and maltodextrin (MD) were set. • Glycation of SPI with MD was accelerated by ultrasonic treatment. • Ultrasonic treatment altered secondary and tertiary structures of the conjugates. • Ultrasound exposed the hydrophobic and sulfhydryl groups of the conjugates. • Appropriate ultrasound treatment improved the gelation properties of the conjugates. [ABSTRACT FROM AUTHOR]

In this study, anaerobic digestion of sewage sludge with different ultrasonic pretreatment (USp) conditions was investigated. USp were applied at a constant ultrasonic density of 0.5 W/mL with sonication times of 0–240 min. While the methane yield of the untreated (control) reactor was 170.1 ± 4.7 mL/g volatile solids (VS), the highest methane yield was 266.1 ± 7.5 mL/g VS in the reactor where sonication was applied for 120 min. Actual specific energy input (SE A)/nominal specific energy input (SE N) ratios after USps were measured for pretreatment yield. These values varied between 77.0 and 14.87% according to different sonication times. Sonication times of more than 30 min did not significantly increase the methane yield due to possible reflocculation. After the USps, various cumulative methane yields were predicted via the modified Gompertz Model, modified Logistic Model, and Artificial Neural Network (ANN) model (Scenario 1); of these the ANN model made predictions that were closest to the experimental data. In the other part of the study, ANN was trained by experimental pretreatment conditions and methane yields were successfully predicted by taking different USp parameters (different sonication times, SE A values and incremental soluble chemical oxygen demand % values) as input variables (Scenarios 2, 3 and 4). Regression analyses showed values close to 1, indicating that the prediction of the ANN model correlated linearly with experimental data. Image 1 • Anaerobic digestion of ultrasonic pretreated sewage sludge was investigated. • Pretreatments were applied at 0.5 W/mL and in the range of 0.5–240 min. • Sonication of more than 30 min did not significantly increase the methane yields. • The cumulative methane yields were predicted via Artificial Neural Network model. [ABSTRACT FROM AUTHOR]

Clay sand casting generates a large amount of foundry dust (FD), and the presence of coal powder in the FD makes it difficult to recycle and utilize. The landfill of the FD creates a serious environmental pollution and wastes a valuable resource. To improve the above situation, the FD was analyzed and characterized by X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD) and electron probe microanalyzer (EPMA). An ultrasonic-assisted flotation process was developed for the comprehensive utilization of the FD, and the effects of ultrasonic time on the flotation performance and flotation kinetics were investigated. In addition, the two-stage flotation of the FD was conducted. Obtained results showed that the FD mainly consisted of coal powder and clay minerals, and the coal powder was covered by clay minerals. The separation efficiency of the coal powder and clay minerals can be significantly enhanced by ultrasonic pretreatment, and the optimal ultrasonic time was 30 min. The flotation kinetics analysis results indicated that the first-order model with rectangular distribution was more reasonable for the data fitting of the ultrasonic-assisted flotation. Furthermore, the concentrate and tailings obtained by the two-stage flotation had achieved an acceptable result, favoring the comprehensive utilization of the FD. ga1 • The particle characteristics of the foundry dust (FD) were systematically investigated. • The optimal experimental conditions were obtained. • The effect of ultrasonic time on the flotation kinetics was analyzed. • The feasibility of ultrasonic-assisted flotation process for separating the coal powder and clay minerals from the FD was verified. [ABSTRACT FROM AUTHOR]

• Sodium citrate-ultrasonic pretreatment was applied to enhance bioH 2 yield of sludge. • Pretreatment obviously disrupted the sludge flocs and promoted soluble COD. • Pretreatment improved the H 2 yield by 604.2% and shortened the lag phase. • Energy conversion efficiency increased from 7.4% to 32.8% through pretreatment. • Pretreatment promoted the abundance of H 2 -producing bacteria in the fermenter. Proper pretreatment of waste activated sludge is commonly needed before biohydrogen fermentation due to its complex floc structure. Considering that the outer-layer extracellular polymeric substances (EPS) could restrict the disintegration of inner-layer microbial cells during the pretreatment of sludge, this study firstly applied sodium citrate pretreatment (0.3 g/g-TSS) for removing EPS from sludge flocs, followed by ultrasonic pretreatment (2 W/mL, 15 min), which aimed to enhance the disintegration efficiency. The subsequent hydrogen fermentation performance was tested in batch mode at 37 °C and initial pH 7.0. Results showed that the combined sodium citrate-ultrasonic pretreatment significantly disrupted the sludge floc structure and promoted soluble COD concentration by 157.5 times, which synergistically enhanced the biohydrogen fermentation performance. The maximum hydrogen yield of 38.8 mL/g-VS added was achieved with the combined pretreatment, which was 604.2%, 155.1%, and 92.6% higher compared to the control, individual ultrasonic pretreatment, and individual sodium citrate pretreatment, respectively. Correspondingly, the energy conversion efficiency increased from 7.4% to 32.8% through the combined pretreatment. The combined pretreatment also enhanced the organics utilization, induced a more efficient fermentative pathway, and shortened the hydrogen-generating lag phase. More enrichment of hydrogen-producing bacteria, especially the genera Clostridium sensu stricto and Paraclostridium , was responsible for the synergistic enhancement in hydrogen yield and energy conversion efficiency. The present work puts forward an effective and eco-friendly pretreatment approach for enhancing bioenergy recovery from waste activated sludge. [ABSTRACT FROM AUTHOR]