磁铁矿对厌氧消化产甲烷的影响

Effect of Magnetite on Methane Production of Anaerobic Digestion

为了提高厌氧消化的产气效率,考察了添加磁铁矿对厌氧消化产甲烷的影响,通过条件优化试验,确定磁铁矿促进产气的最佳粒径及投量;通过对比试验,确定磁铁矿及Fe^2+/Fe^3+对厌氧产甲烷的影响因素;通过加氢试验,确定磁铁矿对产甲烷的促进方式。结果表明,当磁铁矿粒径为100~150nm、投加量为20mmol/L(以铁原子计,负荷为10.3gFe3O4/gVS)时厌氧消化产甲烷效果最佳,累计产甲烷量达到154mL,可使产气率提高51%;磁铁矿并不是通过释放Fe^2+/Fe^3+来促进厌氧消化产甲烷过程,而是磁铁矿颗粒作为乙酸钠和二氧化碳还原甲烷菌之间的电子通道,促进了厌氧微生物的种间电子转移,从而提高了甲烷产量。

The effect of adding magnetite on methane production of anaerobic digestion was investigated to improve the gas production efficiency. The optimum particle size and dosage of magnetite was determined by conditional optimization tests, the influencing factors of magnetite and Fe^2+/Fe^3+ on anaerobic methane production were determined by comparative tests, and the promotion mechanism of magnetite to methane production was determined by adding hydrogen tests. Results showed that the optimum methane production of anaerobic digestion was achieved when the particle size was 100-150 nm and the dosage was 20 mmol/L ( measured by iron atom, load of 10. 3 gFe3O4/gVS). The cumulative CH4 production reached 154 mL, and the gas production rate could be improved by 51 %. The anaerobic digestion was not promoted by releasing Fe^2+/Fe^3+ from magnetite. Instead, magnetite particles acted as electron channels between sodium acetate and carbon dioxide reduction methanogen . It promoted the direct interspecies electron transfer ( DIET) of anaerobic microorganisms, which thus increased the yield of CH4.