Evaluation of the optimal washing conditions for dioxin-contaminated soils from the circumference of an incinerator

Abstract

The optimal soil-washing conditions for dioxins were estimated on a soil sample from the circumference of an incinerator in Nose City, Osaka, Japan. The solvents ethanol, methanol, and acetone, together with a surfactant (100% of each) could extract 40% of the dioxins from contaminated soil at room temperature. From among these solvents, ethanol was chosen for a study on how to optimize the extraction conditions because of its low toxicity and its economic advantages. The time-course of the agitation showed that the extraction rate increased for 1 min, and thereafter the rate decreased. Therefore, the agitation time was fixed at 1 min. To estimate the effect of temperature on the extraction rate, the extraction temperature was changed. The amount of dioxins extracted was largest at the boiling point of ethanol (78.3°C), giving about 76% extraction. Furthermore, at this temperature, almost 100% of the dioxins in the contaminated soil were extracted when the ratio of water to ethanol was 20%.

Efficacy of Indigenously Prepared Sugarcane and Pineapple Wine Solvents for Washing Highly Dioxin-Contaminated Field Soils

“…The removal efficiencies of the control washing experiment were 1,2,3,4,6,7,8-HpCDF (35.67%), 1,2,3,4,6,7,8-HpCDD (46.15%), OCDF (33.94%), and OCDD (15.55%). It seems that different from other studies [6,26,27], our washing experiment with sugarcane wine as a solvent seemed to result in almost no distinct selective removal of dioxin congeners as the removal percentages of different congeners were not much different, which again indicates the non-selectivity washing potential of sugarcane wine. Although the highest and lowest removal percentages were 85.2% (OCDD) and 72.0% (1,2,3,4,6,7,8-HpCDF), it should be noted that we conducted our washing experiment on contaminated field soil, of which the characteristics may greatly vary and considerably affect the removal efficiency [3,6].…”

“…Each washing cycle took sixty minutes under an ultrasonic set temperature of 30 • C (to represent the ambient temperature in the contaminated site in southern Taiwan). Our washing experiments were performed under the conditions (ambient temperatures and a relatively low agitation-700 rpm) that should be energy-advantageous according to Nakamiya, et al [26], Meguro, et al [27] and Jonsson, Lind, Lundstedt, Haglund and Tysklind [6]. After treatment, the particles were allowed to settle before the liquid phase was vacuum-filtered through a 110 nm hydrophilic membrane filter (Millipore, Billerica, MA, USA).…”

Optimization of extraction parameters on the isolation of phenolic compounds from sour cherry (Prunus cerasus L.) pomace

“…There are several drawbacks to use EtOH for extracting natural compounds from plant tissues such as its less extraction efficiency and difficulty to remove from media. However, EtOH is preferred in food processing systems as it is the least hazardous -toxic solvent (Abou-Arab et al 2011;Gould et al 2009;Nakamiya et al 2003) and considered as natural (Ferreira-Dias et al 2003) and safe for human consumption (Pompeu et al 2009;Dai and Mumper 2010). In all obtained extracts, individual anthocyanins and non-anthocyanin phenolics were determined by using HPLC equipped with UV/Vis PDA detector besides spectrophotometric TPC and TA analyses.…”

Chemical extraction of organic carbon to reduce the leaching potential risk from MSWI bottom ash

“…Nagib and Inoue [19] also used acetic acid for heavy metal extraction from MSWI fly ash. Nakamiya et al [20] developed optimum washing conditions for contaminated soil with four to eight chlorinated dibenzo-p-dioxins and dibenzofurans. However, the use of an organic acid for organic carbon removal from incinerator ash has not been studied yet.…”