Effect of ultrasonication on polymerization of silicic acid in geothermal water

Abstract

To prevent silica scale formation on solid surfaces in geothermal water, the changes in silica concentration by ultrasonication were examined. The polymerization rate of monosilicic acid was enhanced by ultrasonication at 500 kHz and was maximum at pH = 8.5. This is because hydroxyl radicals accelerate the reaction between monosilicic and polysilicic acids. Large polymer particles were formed by ultrasonication at 500 kHz. The formation ratio of large particles increased with ultrasonic power and was maximum at pH = 6.0. These results indicate the possibility of the reduction in monosilicic concentration before silica scale formation.

Desorption of CO2from low concentration monoethanolamine solutions using calcium chloride and ultrasound irradiation

“…The ultrasound power that reached the flask was found to be 11.8 W using a calorimetric calculation method. 33) A 30 ml solution containing MEA at a low concentration (0.2 mol=l) was prepared from MEA (Wako Pure Chemicals Industries) and ion-free water (prepared by passing water through an ion exchange column). A mixture of 10% CO 2 and 90% N 2 (called inlet gas) was injected into the MEA solution at 200 ml=min for 30 min while the solution was stirred (at 750 rpm) and kept at 25 °C.…”

Sonochemical effect and pore structure tuning of silica xerogel by ultrasonic irradiation of semi-solid hydrogel

“…Although there is no example of ultrasonic irradiation of the semi-solid hydrogel, it has been reported that hydrolysis and condensation rates were improved when using ultrasonic irradiation in a solution in sol–gel synthesis [26] , [27] . It is known that the hydrogels are not completely solid and have some degree of fluidity, and that the reactions that affect the structure and properties of the gel occur inside the gel [28] .…”

Catalytic effect on ultrasonic decomposition of cellulose

“…13) Such a decomposition method utilizes the physical and chemical properties of ultrasonic waves by the direct contact of cellulose and ultrasonic horn tips. [14][15][16][17][18][19][20][21] It has been clarified that ultrasonic welding in water for filter paper containing a high cellulose content can synthesize physiologically functional substances such as oligosaccharides, furfural, and 5-hydroxymethyfurfural (5-HMF) by hydrolysis and dehydration reactions. If glucose could be obtained by this method, ethanol could then be generated by a general fermentation process.…”