Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, No. 932 South Lushan Road, Changsha, 410083, People's Republic of China.
Environ Sci Pollut Res Int. 2019 Jul;26(19):19434-19444. doi: 10.1007/s11356-019-05195-x. Epub 2019 May 10.
The feasibility of anaerobic digestion on the release of biogas and heavy metals from contaminated rice straw pretreated with NaOH solution was studied. The results show that NaOH pretreatment can significantly boost the release of biogas and heavy metals from rice straw using anaerobic digestion. Under the optimal conditions for biomass pretreated 6% (w/w) NaOH with a solid-to-solution ratio of 1:20, total biogas and methane yields of 446.3 mL/g and 263.5 mL/g volatile solids were achieved, which were 22.18% and 41.59% higher than those of the control without NaOH pretreatment, respectively, and the release percentages of Cd, Pb, Cu, and Zn from rice straw reached 86.95-97.69%. The release of heavy metals from rice straw can contribute to both the degradation of lignin by NaOH pretreatment and the utilization/transformation of lignocellulose via anaerobic digestion. The acidification levels and total volatile fatty acid contents significantly influence on the release of heavy metals. Based on the Illumina HiSeq sequencing analysis, the dominant phyla in the biogas residues were proteolytic (Bacteroidetes) and hydrogen-producing (Firmicutes) bacteria, while the growth of Methanospirillum and Methanosaeta in anaerobically digested effluent was promoted. The results revealed that anaerobic digestion combined with NaOH pretreatment is suitable for the disposal of heavy metal-contaminated biomass.
研究了用氢氧化钠溶液预处理污染稻草后进行厌氧消化释放沼气和重金属的可行性。结果表明，氢氧化钠预处理可以显著提高稻草在厌氧消化过程中沼气和重金属的释放。在生物质用 6%（w/w）氢氧化钠预处理，固液比为 1:20 的最佳条件下，总沼气和甲烷产量分别达到 446.3 mL/g 和 263.5 mL/g 挥发性固体，比没有氢氧化钠预处理的对照组分别提高了 22.18%和 41.59%，稻草中 Cd、Pb、Cu 和 Zn 的释放率达到 86.95-97.69%。稻草中重金属的释放既有助于氢氧化钠预处理对木质素的降解，也有助于厌氧消化过程中木质纤维素的利用/转化。酸化水平和总挥发性脂肪酸含量对重金属的释放有显著影响。基于 Illumina HiSeq 测序分析，沼气残留物中的优势菌群是蛋白水解菌（拟杆菌门）和产氢菌（厚壁菌门），而在厌氧消化废水中促进了 Methanospirillum 和 Methanosaeta 的生长。结果表明，厌氧消化结合氢氧化钠预处理适合处理重金属污染的生物质。
