Ultrasonic pre-treatment

The first step in the progression of a sonochemical process from laboratory to large scale is to determine whether the ultrasonic enhancement is the result of a mechanical or a truly chemical effect. If it is mechanical then ultrasonic pre-treatment of a slurry may be all that is required before the reacting system is subjected to a subsequent conventional type reaction. If the effect is truly sonochemical, however, then sonication must be provided during the reaction itself. The second decision to be made is whether the reactor should be of the batch or flow type. Whichever type is to be used there are only three basic ways in which ultrasonic energy can be introduced to the reacting medium (Table 10.9). Several different types of ultrasonic reactors are currently available (Table 10.10). 

Yunus, R., Salleh, S. F., Abdullah, N., Biak, D. R. A. Effect of ultrasonic pre-treatment on low temperature acid hydrolysis of oil palm empty fruit bunch. Bioresource Technology 2010,101,9792-9796. 

Shah, S., Gupta, M.N., 2008. The effect of ultrasonic pre-treatment on the catalytic activity of lipases in aqueous and non-aqueous media. Chemistry Central Journal 2. 

Pre-treatment of the electrode substrate, which involves polishing, sonicating, and rinsing. The electrode can be pohshed using diamond pastes or alumina, followed by ultrasonic cleaning in water, acetone, or ethanol, and is then rinsed to obtain a clean surface. 

Ultrasound involves the use of ultrasonic energy to enhance the transdermal delivery of solutes either simultaneously or via pre-treatment and is frequently referred to as... 

For example, NIR spectra are temperature-sensitive, so control to 2°C is required. Ultrasonics using two probes at 5 MHz offers the possibility of a robust and less expensive method, but it is still under development and there are few commercially available systems. Chemometrics (Section 3.5) offers the best method of data analysis, and, by using PLS with three different data pre-treatments, it was possible to obtain real-time values of the composition of a fire-retardant to better than 0.1% accuracy (Fischer et al, 2006). 

Cotton samples required no pre-treatment. Glass slides were ultrasonicated for 30 min in a 10% solution of deconex 11 UNIVERSAL (Borer Chemie AG, Switzerland) at 50°C, rinsed with deionized water and dried under a nitrogen flow. Aluminum samples were ultrasonicated in chloroform for 30 min and rinsed with deionized water. A laboratory plasma machine Femto from Diener Electronic (Germany) was used for plasma activation of PDMS and aluminum substrates using oxygen as process gas. After the plasma activation the substrates were rinsed with water and dried in a nitrogen stream. The activated substrates were used immediately. 

McDermott B, Chalmers A, Goodwin J. (2001). Ultrasonication as a pre-treatment method for the enhancement of the psychrophihc anaetohic digestion of aquaculture effluents. Environ Technol, 22, 823-830. 

Rice husk Pre-treatment with hexane/ethanol/water in soxhlet, delignified with 5% (w/v) in autoclave at 121°C. The husk is oxidized with 2% (v/v) HjOj and 0.2% (v/v) (teraacetylethylenediamine) (TAED) for 12 h at 48°C. Cellulose further treated with 80% (v/v) acetic acid and 70% (v/v) HNO3 at 120°C for 30 min. and cellulose dispersed in deionized water by ultrasonic treatment. Rosa et al. (2012)... 

No surface pre-treatment was carried out apart from ultrasonic cleaning in n-hexane, acetone and methanol, 15 min each. This surface condition was chosen to test an as-received surface in all substrates in accordance with the work of Jacob and colleagues [13], who reported that silane coupling agents are most effective on untreated aluminium alloys. 

The fust pre-treatment procedure for non-aqueous formulations is represented by the homogenisation of the sample that is obtained by stirring, ultrasonication or centrifugation and filtration. Sometimes, heating or cooling processes are employed, to favour substance transport between phases or to induce precipitation. 

Esclapez MD, Saez V, Milan-Yanez D et al (2010) Sonochemical treatment of water poulled with trichloroacetic acid from sonovoltammetry to pre-pilot plant scale. Ultrason Sonochem 17 1010-1020... 

The influence of neutral polymer polyethylene glycol and two surfactants with different charge, anionic sodium dodecylsulfate and cationic cetyltrimethylammonium bromide, on the intercalation of pre-formed Au nanoparticles into a clay matrix under ultrasonic treatment has been investigated. The polymer (surfactant) addition has been used to modify the active surface area of NaLmontmorillonite and to change the interlamellar space between the clay layers. Then, intercalated polymer (surfactant) in clay composites has been successfully replaced by Au nanoparticles under sonication. 

In another effort to further reduce the concentrations of chemicals in the preoxidation solution without loss of decontamination efficiency, a dilute mixture of permangante and chromic acid is used in the VS (Very Soft) procedure (Heess et al., 1989 Schenker et al., 1989). In this process, the pre-oxidation step is conducted at 70 C, followed by a reduction step with oxalic acid solution at 30 to 35 C. Using a two-cycle operation supported by ultrasonic treatment, decontamination factors on the order of 10 to 50 have been reported when PWR main coolant pumps were treated. 

The pre-analytical handling of the urine samples requires notice of the low solubility of various purine and pyrimidine bases such as xanthine, uric acid, dihydroxyadenine, and orotic acid. Care should be taken to dissolve all concrements by gently heating and ultrasonic treatment. All analytes are better soluble at a high pH. 

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