摘要
利用微波反应器在500~900℃的目标温度下,高温热解干污泥与Si C混合物(质量比为2.5∶1)以制取不同污泥焦,选取改进欧盟BCR逐级提取法对微波热解前后污泥焦中重金属(Cr、Cu、Pb、Ni)形态变化进行分析。同时对微波污泥热解焦进行RAC风险评估,探寻微波热解固定效能与污泥焦使用安全性与可行性。结果表明,随着微波热解温度的升高,重金属中残渣态(F4)大幅增加稳定性显著改善,与原样相比,Cr与Pb的可氧化态(F3)明显减少,分别由原样中73.86%和51.96%下降至5.98%和4.47%,Cu的可氧化态(F3)在500℃以上变化不明显。此外,微波热解焦中Ni的风险系数显著降低,其RAC形态风险系数由33.23骤降至0.78,其他3种重金属的风险系数也有不同程度的降低。
Bio-chars were obtained from sewage sludge using a microwave reactor with Si C（ quality ratio of2. 5 ∶ 1） as the microwave absorber at a temperature ranging from 500 ℃ to 900 ℃. The modified BCR（ European Community Bureau of Reference） sequential extraction procedure was used to analyze the species transformation of Cr,Cu,Pb,and Ni in sewage sludge and bio-chars. The environmental risk of heavy metals in the biochars was assessed according to the risk assessment code（ RAC） in order to study the immobilization of heavy metals in residues of microwave induced pyrolysis and to assess the utilization safety and feasibility of bio-chars from sewage sludge. The results showed that with the increase of the pyrolysis temperature,the Residual Fraction（ F4） in heavy metals increased substantially,and the stability of the heavy metals in bio-chars improved significantly. Compared to the original sample,the oxidizable fraction of Cr and Pb decreased remarkably from 73. 86%and 51. 96% to 5. 98% and 4. 47%,respectively,while the change in the oxidizable fraction in Cu was not obvious when the temperature was higher than 500 ℃. Additionally,the environmental risk of Ni in bio-chars was greatly reduced,its RAC code decreased sharply from 33. 23 to 0. 78,and the risk factors of the other three heavy metals did not decrease uniformly.
作者
郭子逸
邵敬爱
王贤华
张世红
陈汉平
GUO Ziyi SHAO Jing＇ai WANG Xianhua ZHANG Shihong CHEN Hanping(State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, Chin)
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第3期1801-1806,共6页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(51661145010
51576088)
华中科技大学自主创新基金资助项目(2014TS118)
关键词
微波热解
重金属
BCR
风险评估
microwave pyrolysis
heavy metals
BCR
risk assessment
