膨润土对猪粪厌氧发酵重金属铬钝化的影响  

Effect of pig manure with bentonite on chromium passivation in anaerobic fermentation

作　　者：李轶[1] 宫兴隆 崔铁浩 荣方舟 张轩轩 张镇[1] 谷士艳[1] 易维明[2] Li Yi;Gong Xinglong;Cui Tiehao;Rong Fangzhou;Zhang Xuanxuan;Zhang Zhen;Gu Shiyan;Yi Weiming(College of Engineering,Shenyang Agricultural University,Shenyang 110866,China;College of Agricultural Engineering and Food Science,Shandong University of Technology,Zibo 255049,China)

机构地区：[1]沈阳农业大学工程学院,沈阳110866 [2]山东理工大学农业工程与食品科学学院,淄博255049

出　　处：《农业工程学报》2021年第8期195-203,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：辽宁省自然基金面上重点项目(20170540813);辽宁省教育厅项目。

摘　　要：随着饲料工业的发展,铬(Cr)等重金属元素作为饲料添加剂在规模化养猪场中广泛应用,且由于猪对重金属吸收利用率低,Cr等重金属元素积累在猪粪中。厌氧发酵是中国政府倡导的处理畜禽粪污的有效途径,但经厌氧发酵,重金属仍残留在沼肥中。重金属的危害与其形态密切相关。因此,为减少沼肥中重金属污染、提高其资源化安全利用提供科学依据,该试验以猪粪为发酵原料,添加5%干物质含量的天然/微波膨润土(微波加热2、4、8min),厌氧发酵时间为40d,在温度为35℃、接种物量为30%、pH值为7、总固体质量分数为10%的条件下进行试验,研究猪粪及其添加天然/微波膨润土厌氧发酵对产气特性、重金属铬(Cr)的钝化效果的影响,并采用光谱、能谱分析其钝化机制。结果表明,猪粪添加膨润土厌氧发酵总产气量、平均甲烷体积分数、重金属Cr残渣态含量占比及其有效态钝化效果均显著高于猪粪单独厌氧发酵处理,短时间微波改性处理(2和4min)显著高于天然膨润土处理(P<0.05),而当微波处理膨润土时间较长时(8min)时,上述指标反而比短微波时间组下降,上述指标最佳膨润土微波加热时间均为4min;傅里叶红外光谱及其特征参数比值显示,厌氧发酵后沼渣中碳水化合物、羧酸盐、脂肪族化合物等含量减少,芳香族化合物等含量增加,添加天然膨润土处理促进了沼渣中有机质转化为腐殖质,且添加微波改性膨润土强化了腐殖化程度;扫描电镜及能谱分析显示,猪粪主要由不规则有机质组成,厌氧发酵后转化为腐殖质,添加膨润土促进了沼渣腐殖化过程。经过微波加热处理后膨润土表面由光滑致密变为粗糙多孔,为重金属Cr提供了更多的吸附位点,提高了腐殖质和膨润土对重金属的钝化能力。研究结果可为畜禽粪便厌氧发酵重金属钝化提供参考。Heavy metals such as chromium(Cr)have widely been used as feed additives in large-scale pig farms with the development of the feed industry in recent years.Most heavy metals have posed increasingly serious pollution and subsequent resource utilization of livestock and poultry manure,due to the low digestion and absorption of heavy metals.Anaerobic fermentation is an effective way to treat livestock and poultry manure.However,heavy metals still remain in the biogas fertilizer after treatment,where heavy metal contamination depends mainly on their forms.Taking heavy metal Cr as the research object,this study aims to investigate Cr passivation mechanism in the pig manure with bentonite after anaerobic fermentation.Pig manure was selected as the raw material,where the natural/microwave bentonite with 5%dry matter content was added(microwave heating 2,4 and 8 min).The duration of anaerobic fermentation was 40 days at the temperature of 35℃,inoculum quantity of 30%raw material,10%total solid,and pH value of 7.Five treatments were included:CK group was fermented with pig manure alone;TP group,the natural bentonite was added to pig manure;2WP group was the pig manure with 2 min microwave bentonite;4WP group was the pig manure with 4 min microwave bentonite;8WP group was the pig manure with 8 min microwave bentonite.Each treatment was repeated 4 times for high accuracy.As such,the objective of the experiment was to explore the biogas production characteristics of natural/microwave bentonite added to pig manure,morphological changes of heavy metal Cr,and passivation effect in anaerobic fermentation.Fourier Transform Infrared spectrometer(FTIR),and scanning electron microscope/energy dispersive spectrum(SEM-EDS)were utilized to characterize microstructure and morphology of compounds in the biogas residues after anaerobic fermentation.The results show that the total gas production,the average volume fraction of methane,the proportion of Cr residual state,and the effective passivation effect of pig manure with bentonite in

关 键 词：重金属 猪粪 厌氧发酵 膨润土 钝化 FTIR SEM-EDS 

分 类 号：S216.4[农业科学—农业机械化工程] X713[农业科学—农业工程]