| Soils have been contaminated with heavy metals(HMs) and organic pollutants which were resulted from industry and agricultural development or excessive resources consumption.It posts threat to the growth of animal and plant, and even human live due to the accumulation and distribution behavior of contaminants in soils. Therefore, to find advanced and effective soil remediation technology is necessary for human people. Up till now, it has been already aware that most contaminants were existed as combined pollution,such as HMs-PAHs。Surfactant Enhanced Remediaton(SER) is one of the most potential soil remediation technology. But it was often applied to single type contamination due to limitation of the convetional surfactants. Most of surfactants pose high biotoxicity, high biorecalcitrance and low biodegradability, which affect the growth of edaphon and even lead to second pollution.Thus, it us the key to find environment friendly surfactant is the key for SER. In this study, a novel chelating surfactant, Sodium N-auroyl ethylenediamine triacetate(LED3A) was applied to copper-phenanthrene desorption. LED3 A is born with surfactivity and chelation power,which might desorb organic contaminant and heavy metal simultaneously. Meanwhile,LED3 A possessed no toxicity and biodegradability, which is more environmentally acceptable.Batch washing process was used in this study, due to discuss the desorption efficiency for Cu, Cd, Cu-Cd, phenanthrene and Cu-phenanthrene contaminated soil. The washing parameters tested in the study were the LED3 A concentration, contact time, pH value of solution, temperature, water-soil ratio and co-existing cations. The results presented below:(1) The equilibrium time for Cu, Cd and Cu-Cd were 600 min, 720 min and 720 min especially. Pseudo-second-order equation proviede most accurate fit to the date. The desorption value for Cu and Cd andwere increased as LED3 A concentration increasing. But for Cu-Cd, the desorptin value increased at low LED3 A concentration and then decreased at high concentration, it reached highest value at concentration of 16000 mg/L. The desorption value for Cu-Cd were 35% and 40%, respectively. pH value affect the desorption rate of heavy metals, the highest desorption rates of Cu, Cd and Cu-Cd were 40%,35%, 30% and45% at pH 10. The sequence of effect of water-soil ratio on contaminant removal was in the order of 20:1 >15:1 > 10:1. The efficiency of contaminant removal increased withtemperature(15, 25 and 35oC) increasing. The influences of co-existing cations Na+and Ca2+on the contaminant desorption depended upon the type and concentration of cations.Comparing to the desorption efficiency of single HMs pollutant and combined HMs pollutant,the Cu sinergism(2) The equilibrium time for phenanthrene, Cu-phenanthrene were 300 min, 720 min and 200 min especially, the values were 35%, 55% and12%. Pseudo-second-order equation and Elovich equation provided better description of phenanthrene and Cu-phenanthrene desorption. The desorption value for phenanthrene and Cu-phenanthrene were increased as LED3 A concentration increasing. pH value affect the desorption rate of both HMs and organic pollutions, the sequence of effect of water-soil ratio on contaminant removal was in the order of 20:1 >15:1 > 10:1. The efficiency of contaminant removal increased with temperature(15,25 and 35oC) increasing. The influences of co-existing cations Na+and Ca2+on the contaminant desorption depended upon the type and concentration of cations... |
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