摘要
针对多环芳烃污染土壤热脱附能耗较高的问题,采用K_(2)CO_(3)、CaCO_(3)和Fe2O_(3)等添加剂强化热脱附过程,以降低能耗。通过室内模拟实验研究了热脱附温度、停留时间、添加剂种类与投加量等对菲(Phe)去除效果的影响,分析了热脱附去除过程、能耗以及热脱附后土壤理化性质的变化。结果表明:在100、200℃下停留30 min,投加5.0%(质量分数)的K_(2)CO_(3)、CaCO_(3)和Fe2O_(3)均能显著提高Phe的去除率(p<0.05),效果最好的是K_(2)CO_(3)。添加剂投加后土壤导热系数的提高可能是促进热脱附的重要原因。200℃停留30 min时,Phe去除率随K_(2)CO_(3)投加量增加呈现先增加后下降趋势,最优投加量为5.0%,此时去除率为85.90%,较无添加剂组提高了11.82百分点。200℃时,投加5.0%的K_(2)CO_(3)可将脱附速率常数提高85.71%,单位能耗降低56.78%。K_(2)CO_(3)强化热脱附后土壤黏粒占比增加,土壤粒径变小。在Phe污染土壤热脱附过程中投加适量的K_(2)CO_(3)有望在保证污染物去除率的同时大幅降低修复能耗。
Aiming at the problem of high energy consumption for thermal desorption of PAH-contaminated soil,additives such as K_(2)CO_(3),CaCO_(3)and K_(2)CO_(3)were used to enhance its thermal desorption to reduce energy consumption.The effects of thermal desorption temperature,treatment time,type and dosage of additives on the removal efficiency of phenanthrene(Phe)were studied through laboratory simulation experiments.The removal process,energy consumption and changes of physical and chemical properties of soil after desorption were analyzed.The results showed that thermal desorption at 100,200℃for 30 min,5.0%(mass fraction)K_(2)CO_(3),CaCO_(3)and K_(2)CO_(3)addition could significantly increase the removal efficiency of Phe(p<0.05),and K_(2)CO_(3)had the best improvement effect.The increase of soil thermal conductivity after adding additives might be an important reason to promote thermal desorption.The removal efficiency of Phe first increased and then decreased with the increase of K_(2)CO_(3)dosage,the optimum dosage of K_(2)CO_(3)at 200℃for 30 min was 5.0%,and the removal efficiency under this dosage was 85.90%,which was 11.82 percent points higher than that of the non-additive group.5.0%of K_(2)CO_(3)addition could also accelerate the process of thermal desorption and reduce the energy consumption.At 200℃,the thermal desorption rate constant increased by 85.71%and unit energy consumption decreased by 56.78%after 5.0%K_(2)CO_(3)addition.And soil clay content increased and soil particle size decreased after thermal desorption with K_(2)CO_(3)addition.Studies showed that in the process of low temperature thermal desorption of Phe contaminated soil,adding an appropriate amount of K_(2)CO_(3)was expected to ensure the pollution removal efficiency and greatly reduce the energy consumption of remediation.
作者
叶春梅
YE Chunmei(Shanghai Academy of Environmental Science,Shanghai 200233;State Environmental Protection Engineering Center for Urban Soil Contamination Control and Remediation,Shanghai 200233)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2023年第5期595-601,共7页
Environmental Pollution & Control
基金
国家重点研发计划项目(No.2019YFC1805702)。
关键词
菲
污染土壤
添加剂
热脱附
能耗
phenanthrene
contaminated soil
additive
thermal desorption
energy consumption
作者简介
叶春梅,女,1995年生,硕士,助理工程师,研究方向为有机污染土壤修复。
