热脱附对荧蒽污染土壤的修复效果及后续利用

Effect of Thermal Desorption on Fluoranthene-contaminated Soil and Its Subsequent Use

为探究热脱附参数对荧蒽去除效率的影响及热脱附后土壤后续利用类型,文章采用异位修复试验,将荧蒽污染土壤在不同温度(100~500℃)和不同处理时间(10~80 min)下进行热脱附处理,运用扫描电镜(SEM)和傅里叶红外光谱(FT-IR)对不同处理条件下的土壤进行性质表征,测定修复前后土壤理化性质。研究结果表明:土壤荧蒽去除率随温度(100~500℃)的增加而增加,但在300~500℃区间内去除率增幅较小。在300℃时荧蒽去除率已达80%。土壤荧蒽去除率在0~50 min内随热脱附时间的增大而增大,在50min时热脱附反应平衡。综合土壤荧蒽去除率和能耗考量,选择300℃和50 min作为热脱附荧蒽适宜参数,此时土壤荧蒽去除率为96.3%。不同温度处理荧蒽土壤的FT-IR和SEM显示,与300℃处理相比,400~500℃处理后土壤微观形态被严重破坏,土壤板结化严重;500℃处理下土壤某一组分上官能团种类出现丢失。300~500℃热脱附处理土壤后,土壤中碱解氮、有机质和阳离子交换量含量随温度的升高而降低,相较原土壤降低43.5%~69.7%、63.4%~89.5%和78.3%~84.4%,但有效磷和速效钾含量升高20.4%~100.6%和256.1%~266.1%。研究表明,土壤热脱附是一种能有效去除荧蒽污染的土壤修复技术,但热脱附修复后的土壤肥力指标流失严重。

In order to explore the influence of thermal desorption parameters on the removal efficiency of fluoranthene and the subsequent types of soil use after thermal desorption,ectopic remediation experiments were used to contaminate the soil contaminated with fluoranthene at different temperatures(100~500℃)and different treatment times(10~80 min),thermal desorption treatment was performed,and scanning electron microscope and Fourier infrared spectroscopy were used to characterize the soil under different treatment conditions,and the physical and chemical properties of the soil before and after restoration were measured.The results show that the thermal desorption temperature is 300℃and the retention time is 50 min.The optimal parameters for thermal desorption are achieved.At this time,the removal rate of soil fluoranthene reaches 96.3%.Increasing the thermal desorption temperature can increase the desorption rate and amount of fluoranthene.Infrared spectral characterization and SEM of fluoranthene soil treated at different temperatures showed that compared with 300℃treatment,the soil micromorphology was severely damaged and soil compaction was severed after treatment at 400~500℃;soil functional group species were lost at 500℃treatment.After thermal desorption treatment of the soil at 300~500℃,the content of alkaline hydrolyzable nitrogen,organic matter and cation exchange in the soil decreased by 43.5%~69.7%,63.4%~89.5%and78.3%~84.4%compared with the original soil,while available phosphorus and available potassium content increased by20.4%~100.6%and 256.1%~266.1%.Soil thermal desorption is a soil remediation technology that can effectively remove fluoranthene pollution.The soil after thermal desorption is suitable for building land.