冻融循环对牦牛粪生物炭吸附氨氮的影响

发布时间：2018-03-25 13:10

  本文选题：生物炭　切入点：冻融循环　出处：《农业环境科学学报》2017年03期

【摘要】：为了解冻融循环(模拟物理老化过程)对不同热解温度下的牦牛粪生物炭吸附氨氮的影响,通过吸附实验,考查牦牛粪生物炭老化前后对氨氮的吸附特性,并采用元素分析、扫描电镜、FTIR、BET-N2等方法分析牦牛粪生物炭的组成及表面结构特性,探讨冻融循环对牦牛粪生物炭吸附氨氮的影响机理。结果表明,牦牛粪生物炭老化前后对氨氮的吸附动力学模型符合准二级动力学,吸附等温模型较符合Freundlich模型。不同热解温度的牦牛粪生物炭对氨氮的吸附作用存在显著性差异,冻融循环作用对热解温度较高的牦牛粪生物炭影响较显著(C020 mg·L~(-1)),氨氮初始浓度为5 mg·L~(-1)时,老化后的生物炭PBC450和PBC600(热解温度分别为450℃和600℃)的吸附量比老化前分别显著提高13.1%、12.4%,去除效率分别为62.6%、55%。PBC450和PBC600的阳离子交换量和比表面积比老化前显著增加,阳离子交换量分别增加9.1%和75.7%,pH值、Zeta电位显著降低,其中阳离子交换量和比表面积是影响牦牛粪生物炭吸附氨氮的主要因素。
[Abstract]:In order to understand the effect of freezing and thawing cycle (simulating physical aging process) on the adsorption of ammonia nitrogen by yak manure biochar at different pyrolysis temperatures, the adsorption characteristics of ammonia nitrogen in yak manure biochar before and after aging were investigated by elemental analysis. The composition and surface structure of biochar in yak manure were analyzed by SEM FTIR BET-N2, and the mechanism of freezing and thawing cycle on the adsorption of ammonia nitrogen in yak dung biochar was discussed. The adsorption kinetics model of ammonia-nitrogen in yak manure biochar before and after aging accorded with quasi-second-order kinetics, and the adsorption isothermal model was more in line with Freundlich model. There was significant difference in the adsorption of ammonia-nitrogen between yak fecal biochar with different pyrolysis temperature. The effect of freeze-thaw cycle on the biochar of yak feces with high pyrolysis temperature was more significant when the initial concentration of ammonia nitrogen was 5 mg / L, and the initial concentration of ammonia was 5 mg / L. After aging, the adsorption capacity of PBC450 and PBC600 (pyrolysis temperature was 450 鈩，

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