络合剂Fe(Ⅱ)EDTA对微藻络合体系的影响

摘要

The high cultivation cost of microalgae was always the significant challenge for the industrial application of microalgaebiodiesel.Based on the perspective of lowering microalgae cultivation cost for facilitating its commercialization,this study explored to examine the potential to couple the cultivation process with the removal of NO from flue gas in the microalgae-Fe(Ⅱ) EDTA system.In this study,the impacts of different concentrations of Fe(Ⅱ) EDTA on NO removal and microalgae growth were investigated.It was found that higher initial concentration delayed the NO escape time in preliminary phase and then achieved high NO removal rate in the stable phase.When the initial concentration of Fe (Ⅱ) EDTA was 20 mmol/L,the NO concentration at the system exit was 93 mg/L,with NO removal efficiency of 76.75％.High concentration of complexing agent was unfavorable for the growth and lipid accumulation of microalgae cell.When the concentration of Fe(Ⅱ) EDTA was 20 mmol/L,OD and lipid content were 0.74 and 9.93％,respectively;while when it was 2 mmol/L,OD and lipid content were 0.69 and 8.89％,respectively.Therefore,to achieve the optimum of the microalgae-complexing agent system,the concentration of Fe(Ⅱ) EDTA should be balanced for both microalgae cell growth,lipid accumulation and NO removal.%高昂的微藻培养成本限制了微藻能源的大规模工业化生产.从降低微藻培养成本的角度出发,将能源微藻的培养与烟道气中脱除NO的两个过程耦联,并使用络合剂Fe(Ⅱ)EDTA提高NO吸收效率.研究通过设置不同的络合剂浓度来观察NO的去除效果和对藻细胞生长、油脂积累的影响.实验发现,络合剂会被系统中的氧化剂氧化而失去络合能力,但微藻可将Fe(Ⅲ)还原成Fe(Ⅱ),系统达到Fe(Ⅱ)浓度平衡,具备持续高效去除NO的能力.当络合剂浓度为20 mmol/L时,系统出口处检出的NO浓度为93 mg/L,NO去除率为76.75％.实验结果还发现,高浓度络合剂不利于微藻细胞的生长和油脂积累,系统反应24 h后两种对应的光密度(OD值)和油脂含量分别为0.82、9.93％和0.69、8.89％.因此,在构建微藻-络合剂体系中,初始络合剂浓度应兼顾NO的去除和细胞生长代谢、油脂积累,使系统效果达到最优.