不同来源污泥热解油中多环芳烃分布特征

Characterization on PAHs distributions in pyrolysis bio-oil from different wastewater sewage sludge

分析了4种不同来源污泥的热解油中16种EPA-PAHs生成分布,并探讨了污泥原样中自由赋存PAHs和污泥泥质特性(碳含量、H/C摩尔比、O/C摩尔比及挥发分含量等)的影响。结果表明,4种来源污泥热解油中均不同程度包含16种EPA-PAHs,∑EPA-PAHs含量分布次序为:工业印染污泥热解油(21.72 mg·kg-1)>生活污泥热解油(14.10 mg·kg-1)>造纸污泥热解油(13.72 mg·kg-1)>食品污泥热解油(5.48 mg·kg-1),且以低环(2R)和中环(3R和4R)PAHs为主,其总量占∑EPA-PAHs的95%以上。热解油中PAHs含量高低与污泥自身赋存的自由PAHs含量具有一定关联;泥质特性对热解油中EPA-PAHs含量分布也呈现了不同程度影响,随着污泥泥质特性变化,3R和4R-PAHs含量变化规律较相似,均在碳含量为30.96%、H/C摩尔比为1.1、O/C摩尔比为0.33和挥发分为35.5%时达到最高水平;2R-PAHs含量在碳含量为20.75%、H/C摩尔比为1.44、O/C摩尔比为0.6和挥发分为46.3%时达到最高水平。

Distribution of sixteen kind of EPA-PAHs in pyrolysis bio-oil from four sorts of different wastewater sewage sludge was investigated.The influences of free PAHs of raw sewage sludge and phi-chemical characteristics（carbon content,H/C molar ratio,O/C molar ratio and volatile content） of the sludge on PAHs distributions were discussed.The results showed that the bio-oil produced from pyrolysis of different sludge contained sixteen kinds of EPA-PAHs in different extent.A decreasing order of content of PAHs in the different bio-oil was as followed：Industrial wastewater sewage sludge in dying（21.72 mg·kg-1） household wastewater sewage sludge（14.10 mg·kg-1） paper manufacturing wastewater sewage sludge（13.72 mg·kg-1） food production wastewater sewage sludge（5.48 mg·kg-1）.The PAHs of bio-oil were majorly consisted of two,three and four rings of PAHs,and their amount was accounted for more than 95% of the total concentrated PAHs.The concentration distributions of different rings of PAHs were closely related with the concentrations of the free PAHs of raw sewage sludge.In addition,it was found that the distributions of PAHs in bio-oil was also dependent of the phi-chemical characteristics of raw sludge.Along with the phi-chemical properties of sludge varied,the PAHs concentrations of three and four rings presented a similar variation trend.Their maximum contents were obtained at 30.96% of carbon content,1.1 of H/C molar ratio,0.33 of O/C molar ratio and 35.5% of volatile contents.The maximum content of two rings of PAHs was obtained at 20.75% of carbon content,1.44 of H/C molar ratio,0.6 of O/C molar ratio and 46.30% of volatile contents.