A method for determining the content of petroleum hydrocarbons in soil

In this paper, ultrasonic - centrifugal extraction - infrared oil meter is used to determine petroleum hydrocarbons in soil.The optimal conditions of ultrasonic centrifugal extraction of petroleum hydrocarbons from soil were investigated by using simulated soil from the extraction agent, ultrasonic temperature, ultrasonic time, ultrasonic power, centrifugal speed, centrifugal time and other factors.The results showed that using tetrachloroethylene as extraction agent, the extraction efficiency of three times reached 88.34% with ultrasonic temperature of 30℃, ultrasonic time of 10min, ultrasonic power of 180W, centrifugal speed of 4000rpm and centrifugation time of 20min in 1% oil-contaminated soil.Under these conditions, the recoveries were 78.97%~96.58% and the relative standard deviations (n=5) of the measured values were 3.82%~12.53%.

Recovery of Boron from Underground Brine by Continuous Centrifugal Extraction with 2-Ethyl-1,3-hexanediol (EHD) and Its Mechanism

In order to economical and environmental-friendly recycle of boron from underground brine, the extraction of boron was carried out in this work by the continuous centrifugal technique using 2-ethyl-1,3-hexanediol (EHD) + sulfonated kerosene (SK) extraction system, and the extraction mechanism was also investigated by the combination of FT-IR with slope method. The results showed that boron can be effectively extracted from underground water with the concentration of boron 5.43 g·L−1 by five-stage centrifugal extraction using 30% EHD + 70% SK at pH = 2.0–3.0, R(O/A) = 1 : 2, and the extraction rate reached 98.46%. Boron in the organic phase can be well five-stage back-extracted by 1.0 mol·L−1·NaOH at R(O/A) = 1 : 1 with a back-extraction rate of 97.00%. About 88.32% boron in the aqueous phase obtained by back-extraction can be recycled in H3BO3 form by evaporation crystallization after acidified to pH < 2.5. The extraction mechanism indicated that the extraction is completed mainly based on the esterification reaction between alcoholic hydroxyl in EHD and -OH in B(OH)3 at the stoichiometric ratio 1 : 1 to generate a stable six-membered ring structure of boric acid ester.