Use of high-frequency ultrasound to intensify the sorption of humic substances from brines

Abstract

To intensify the sorption concentration of humic substances from sodium chloride brines, the use of high-frequency ultrasound has been proposed. The optimal parameters of ultrasound were experimentally established as follows: frequency of 11.0–12.0 MHz, sound intensity of 7.5–8.5 W/cm2, and duration of action not less than 2.0 min. Under the action of high-frequency ultrasound as compared to the use of low-frequency ultrasound, the degree of extraction of humic substances from brines with a concentration of sodium chloride of 150 g/l increases from 91.3–93.2% to 97.3–98.2% and from 93.2–95.0% to 98.1–99.0% on wofatit sorbent and diethylaminoethyl cellulose sorbent, respectively. In addition, the effect of high-frequency ultrasound allows quantitatively sorbing humic substances from more concentrated brines (degree of extraction 90%). Moreover, quantitative sorption of humic substances is possible up to a concentration of sodium chloride of 200 g/l and 250 g/l on the wofatit sorbent and diethylaminoethyl cellulose sorbent, respectively. We developed a method for spectrophotometric determination of the content of humic substances in brines with the lower limits of determination of 0.002 mg/l and 0.001 mg/l for humic acids and fulvic acids, respectively.