高温索氏提取土壤中的可降解聚乙烯蜡残余物及根窖降解评价  

Extraction of Polyethylene Wax Residues by High-temperature Soxhlet Apparatus in Soil and Its Degradation in Root Cellar

作　　者：熊小莉[1] 陈成[2] 罗学刚[2] 

机构地区：[1]四川师范大学化学与材料科学学院,四川成都610068 [2]西南科技大学材料科学与工程学院,四川绵阳621010

出　　处：《广西师范大学学报（自然科学版）》2014年第4期101-107,共7页Journal of Guangxi Normal University:Natural Science Edition

基　　金：十一五国家科技支撑计划资助项目(2007BAE42B04);四川省非金属复合与功能材料重点实验室-省部共建国家重点实验室培育基地开放基金资助项目(10zxfk23);四川师范大学重点项目(11KYL06);四川省教育厅重点项目(14ZA0027)

摘　　要：通过高温索氏提取法采用混合溶剂（V正庚烷∶V二甲苯=1∶4）对土壤中的可降解聚乙烯（PE）残余物（PEW,Mw=5 000）进行分离提取,分别考察了提取时间和土壤类型对PEW提取率及结构和热性质的影响,同时做根窖实验并进行相对分子质量的测定。结果表明,对PEW的提取率随提取时间的增加而增大,2.5h后达最大（92.5%）;提取时间对PEW的分子结构无明显影响,但对PEW的结晶有一定影响,使得熔融温度和结晶温度分别升高1-3℃;提取时间对PEW的平均相对分子质量无明显影响,但会导致相对分子质量分布变窄;土壤类型对PEW的提取率基本没有影响;根窖实验结果表明该提取方法可以用于实际土壤中PEW残余物的降解测试评价,长期跟踪下去还可以评估PE完全降解所需时间。In order to investigate the degradation and the degradation time of degradable polyethylene（PE）film residues after removing the visual pollution into the soil,it is necessary to establish the method of separation and recovery PE residues from soil.PE wax powders（PEW,Mw =5 000）was taken as simulated PE residue,and then they were extracted in soil through the Soxhlet apparatus extraction method on the high-temperature by using mixed solvent（Vheptane∶Vxylene=1∶4）.The PEW samples were characterised by Fourier transform infrared spectroscopy（FT-IR）,high temperature gel permeation chromatography（HT-GPC）,thermal analyzer（DSC）after the separation.The effection of the extraction time and soil types on the molecular structure and thermal properties of PEW were studied.At the same time,the molecular weight of the PEW after buried 1~3 years were determinated by the root cellar experiment.The results showed that the extraction rate increases with extraction time,and it reaches the maximum after 2.5h（92.5%）.The FT-IR spectra illustrates that the molecular structure of PEW is not destroyed during the extraction,but the extraction time has a certain influence on the crystallization of PEW which its melting temperature and crystallization temperature were raised by 1~3 ℃,respectively.The extraction time does not have much influence on average molecular of PEW,but it makes the molecular weight distribution narrow.The PEW recovery is independent of soil type.The root cellar experiment results show that the extraction method can be used to evaluate the degradation of actual PEW residue in soil and assess the total degradation time of PE after long-term tracking down.

关 键 词：分离 高温索氏提取 聚乙烯蜡残余物 土壤 降解 根窖 

分 类 号：X131.3[环境科学与工程—环境科学]