温度和pH值对低木质素碎木反硝化过程的影响

Effects of Temperature and pH on Denitrification Process on Woodchips with Low Lignin Content

木质生物质作为广泛研究的碳源材料,突出问题是反硝化速率缓慢和副产物较多。为此,该文采用碱处理后的低木质素含量碎木作为原料,将反硝化过程细分为碳释放和反硝化阶段,设计温度和pH值的影响因素试验,测定“三氮”、总氮和溶解性有机物(DOC)浓度,以及DOC的光谱特征。结果表明:碳释放和反硝化对温度变化的敏感程度不同,二者的速率在15℃条件下分别为2.6和1.1mg/(g·d),在25℃时分别升高至1.7倍和1.5倍,而在35℃时又分别升高至25℃的1.7和2.1倍;碳释放在pH值5.0和9.0时均受到抑制,而反硝化在pH值9.0条件下明显减弱;亚硝态氮在15℃条件下的峰值最高,占硝态氮去除量的35.7%,而占比值最大的是pH值为9.0的条件;反硝化期间残留DOC占释碳总量的44.6%~52.0%,包括类蛋白和类腐殖酸。

As a widely studied carbon source material,the outstanding problems of woody biomass are slow denitrification rate and more by-products.Therefore,the denitrification process was subdivided into carbon release and denitrification stages by using alkali treated wood with low lignin content as raw materials.Experiments were designed to determine the concentra-tion of“trinitrogen”,total nitrogen and dissolved organic matter(DOC),and the spectral characteristics of DOC.The results showed that the sensitivity of carbon release and denitrification to temperature change was different,while the rates of carbon release and denitrification were 2.6 and 1.1 mg/(g.d)at 15 C,respectively,which increased to 1.7 times and 1.5 times at 25 C,and 1.7 times and 2.1 times at 35 C.Carbon release was inhibited at pH 5.0 and 9.0,while denitrification was obviously weakened at pH 9.0.The peak value of nitrite nitrogen was the highest at 15 C,accounting for 35.7%of nitrate nitrogen removal,and the maximum ratio was at pH 9.0.During denitrification,the residual DOC accounts for 44.6%~52.0%of the total carbon released,including proteinoid and humic acidoid.