生物质水洗时有机物释放的实验研究

Experimental study on release of organic matter during water washing of biomass

为研究生物质水洗滤液的有机成分,提取小麦秸秆、稻壳、玉米秸秆水洗滤液中的有机物,借助气相色谱质谱联用仪(GC-MS)分析滤液成分,考察了30,60,90℃三个水洗温度下滤液有机物种类与质量分数变化.结果表明:生物质水洗滤液中有机物种类随水洗温度的升高而增加;30℃下滤液中的有机物以酯类为主,90℃则以烃类和芳香族类为主;三种生物质30℃下水洗滤液中苯乙烯质量浓度较高,60℃下苯乙烯质量浓度大幅降低,90℃时观察到二次释放苯乙烯;对于稻壳和玉米秸秆,60℃下滤液中邻苯二甲酸二丁酯(DBP)质量浓度分别为1.13×10^(-4)和2.72×10^(-4)mg·L^(-1),而此时小麦秸秆滤液中DBP质量浓度为0.02 mg·L^(-1).所有实验中DBP质量浓度均满足我国相关污水排放标准,但苯乙烯质量浓度高于部分地方标准,水洗滤液还田仍须审慎考虑.

To investigate the organic components in biomass washing leachates,wheat straw,rice hull,and sorghum stalk were water washed.Organic species and their quality fraction were detected by gas chromatography mass spectrometry(GC-MS)tests at three washing temperatures of 30,60,and 90℃.The results show that more species of organics would enter the leachate at a higher temperature.At 30℃,esters are the main organic matter in the leachate.At 90℃,hydrocarbons,as well as aromatics are the main organic matter in the leachate.The concentrations of styrene in the 30℃ leachates of the three biomasses are higher,then reduce at 60℃.The secondary release of styrene is observed at 90℃.For rice husk and corn stalk,the concentrations of dibutyl phthalate(DBP)in the leachates at 60℃ washing temperature are 1.13×10^(-4) and 2.72×10^(-4) mg·L^(-1),respectively.However,the DBP concentration in the wheat straw leachate is 0.02 mg·L^(-1).The concentrations of DBP in all experiments meet the relevant sewage discharge standards in China,but the concentration of styrene is higher than some local standards.So,the return of water leachate to the field still needs careful consideration.