Enhanced Biogas Production from Nanoscale Zero Valent Iron-Amended Anaerobic Bioreactors
Enhanced Biogas Production from Nanoscale Zero Valent Iron-Amended Anaerobic Bioreactors
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DOI：
10.1089/ees.2014.0560
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发表时间：
2015-08-01
影响因子：
1.8
通讯作者：
Wiesner, Mark R.
中科院分区：
文献类型：
--
作者：
Carpenter, Alexis Wells;Laughton, Stephanie N.;Wiesner, Mark R.
描述了向厌氧间歇式反应器添加纳米级零价铁（NZVI）以增强产甲烷活性。测试了两种 NZVI 系统：市售 NZVI (cNZVI) 浆料和新合成的 NZVI (sNZVI) 悬浮液（在添加到反应器之前立即制备）。在这两个系统中，与未经修改的控制反应器相比，添加 NZVI 提高了 pH 值并降低了氧化/还原电位。模型啤酒厂废水的生物降解得到了增强，如在所有测试浓度（1.25-5.0 g Fe/L）下使用 sNZVI 和 cNZVI 改良剂去除化学需氧量有所增加。所有经过 NZVI 改进的生物反应器的甲烷产量均有所增加，添加 2.5 和 5.0 g/L cNZVI 后，甲烷产量最大增加了 28%。添加散装零价铁仅导致甲烷含量增加 5%，这表明使用纳米级颗粒的优势。 NZVI 修正案通过将生物反应器释放的二氧化碳量减少约 58%，进一步改善了沼气的生产。总体而言，在相同铁浓度下，添加 cNZVI 比添加 sNZVI 更有利，因为 sNZVI 的胶体稳定性降低且有效粒径较大。尽管有些人报道了 NZVI 对厌氧微生物的细胞毒性，但本文提出的工作表明，一定粒径和反应性的 NZVI 可以作为厌氧消化器的改良剂，以增强降解并增加产生的沼气的价值，从而产生更节能的厌氧废水处理方法。
Addition of nanoscale zero valent iron (NZVI) to anaerobic batch reactors to enhance methanogenic activity is described. Two NZVI systems were tested: a commercially available NZVI (cNZVI) slurry and a freshly synthesized NZVI (sNZVI) suspension that was prepared immediately before addition to the reactors. In both systems, the addition of NZVI increased pH and decreased oxidation/reduction potential compared with unamended control reactors. Biodegradation of a model brewery wastewater was enhanced as indicated by an increase in chemical oxygen demand removal with both sNZVI and cNZVI amendments at all concentrations tested (1.25-5.0 g Fe/L). Methane production increased for all NZVI-amended bioreactors, with a maximum increase of 28% achieved on the addition of 2.5 and 5.0 g/L cNZVI. Addition of bulk zero-valent iron resulted in only a 5% increase in methane, indicating the advantage of using the nanoscale particles. NZVI amendments further improved produced biogas by decreasing the amount of CO2 released from the bioreactor by approximately 58%. Overall, addition of cNZVI proved more beneficial than the sNZVI at equal iron concentrations, due to decreased colloidal stability and larger effective particle size of sNZVI. Although some have reported cytotoxicity of NZVI to anaerobic microorganisms, work presented here suggests that NZVI of a certain particle size and reactivity can serve as an amendment to anaerobic digesters to enhance degradation and increase the value of the produced biogas, yielding a more energy-efficient anaerobic method for wastewater treatment.