添加木醋液和生物炭对堆肥重金属钝化的影响

腐殖质(HS)是有机肥养分质量的重要指标。在堆肥过程中,生物炭和棉秆木醋液的添加会导致堆体内部环境发生变化,但HS的化学性质变化尚不明确。本研究利用火焰原子吸收仪检测了重金属(HMs)(例如Pb、Cr、Cd、Ni)的形态,运用傅里叶变换红外光谱(FTIR)方法和三维激发发射矩阵荧光光谱(3D-EEM)方法以多个角度表征HS与HMs的络合物。同时,采用数理统计、相关性分析和冗余分析(Redundancy analyses, RDA)比较了试验组的腐熟指标(温度、pH值)、腐殖化能力(HS、富里酸(FA)、胡敏酸(HA)、胡敏酸与富里酸之比(H/F))、官能团等。研究结果显示,木醋液处理能使堆肥腐殖化程度相对较高,且位于波数876～835 cm^-1的峰值明显增强表明芳香结构在不断累积,H/F最终均达到2.3以上。T1处理组生物炭处理的HS含量位于T4和T3处理组之间,H/F最终达到3.67。T1处理组对Cr钝化过程,交换态最终钝化比例至2%。T4处理组在Pb钝化过程中,最终残渣态的比例高达68%。Cd受T4处理组影响较大,最终表现为氧化态分别向交换态、还原态、残渣态转...

Effect of Humus in Compost with Wood Vinegar Liquid and Biochar Addition on Heavy Metal Passivation

Humus (HS) is an important indicator of the nutrient quality of organic fertilisers. During the composting process, the addition of biochar and cotton straw wood vinegar liquid leads to changes in the internal environment of the heap, but the changes in the chemical properties of HS are not clear. The morphology of heavy metals (HMs) (e.g. Pb, Cr, Cd, Ni) was detected by flame atomic absorber, and Fourier transform infrared spectroscopy (FTIR) method and three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) were used to characterise the complexes of HS and HMs from different angles. Meanwhile, mathematical statistics, correlation analysis and redundancy analysis (RDA) were used to compare the decay indices (temperature, pH value), humification capacity (HS, fulvic acid (FA), huminic acid (HA), huminic acid and fulvic acid ratio (H/F)) and functional groups of the test groups. The results of the study showed that the wood vinegar liquid treatment could make the humification of the compost relatively high, and the peak located at 876~835cm-1 was significantly enhanced, indicating the accumulation of aromatic structure, and the H/F finally reached more than 2.3 in all cases. The HS content of the T1 biochar treatment was located between T4 and T3, and the H/F finally reached 3.67. The passivation process of Cr by the T1 vs exchange state final passivation proportion to 2%. T4 treatment group in the Pb passivation process, the proportion of the final residue state was as high as 68%. Cd was more affected by T4, and eventually showed the transfer of 2%, 10% and 11% from the oxidation state to the exchange state, reduction state and residue state, respectively. However, the passivation of Ni by the addition of either biochar or wood vinegar liquid did not show any significant trend during the stacking process, and the proportions of exchange, reduced, oxidized and residual states were stable at 1%~2%, 5%~7%, 26%~35% and 56%~68%, respectively, indicating that the effect of HS on Ni was relatively small in this experiment. FTIR further confirmed the role of HS as a core agronomic and carboxylate-rich basic properties of functional substances. The aromaticity of HS was gradually increased during the composting process, which enhanced the complexing ability with Pb, Cr and Cd ions. In addition, it was found that the wood vinegar liquid with a mass fraction of 1.75% performed better overall in the composting process of the pig manure base. In summary, the following adsorption mechanisms existed for wood vinegar liquid and biochar: the special functional groups of wood vinegar liquid complexed with HMs ions; biochar relied mainly on adsorption with HMs; and the mechanism of Ni in composting may be more inclined to bind with nitrate ions.