生物炭释放的溶解性有机质（DOM）具有复杂的生物地球化学特征, 影响着污染物的迁移与转化和全球碳循环等诸多环境过程。 相比对生物炭理化性质、 结构特征的研究, 生物炭DOM的研究仍相对匮乏, 其中裂解温度驱动下生物炭释放DOM的光谱特征鲜有报道。 以两种常见且具有较好应用前景的生物炭—竹炭（楠竹生物炭）和木炭（柏木生物炭）为研究对象, 通过紫外-可见光谱、 三维荧光光谱结合平行因子法（3DEEMs-PARAFAC）, 研究不同裂解温度下（100～700 ℃）两种生物炭释放DOM的光谱特征。 结果表明, 裂解温度决定两种生物炭释放DOM的潜能及其光谱特征。 裂解温度越高, DOM释放量越小, 且400 ℃是所研究两种生物炭DOM释放的临界裂解温度, 当裂解温度低于400 ℃, 生物炭DOM释放明显, 当裂解温度高于400 ℃, 生物炭释放量很低且趋于稳定。 柏木生物炭的DOM释放量明显高于楠竹生物炭。 低温裂解过程中（<300 ℃）两种生物炭DOM存在大量紫外-可见发色团, 并随着裂解温度上升逐步分解。 通过3DEEMs-PARAFAC从生物炭荧光溶解性有机物（FDOM）中分离出2个类腐殖质荧光物质（C1和C2）及1个类蛋白荧光物质（C3）, 3个荧光组分对裂解温度的响应不同, 类腐殖质荧光强度在300 ℃出现峰值, 而后随裂解温度上升而下降, 类蛋白物质始终随着裂解温度的上升而下降。 低温裂解（<200 ℃）以类蛋白荧光为主, 随着温度上升, 类腐殖质组分占主导。 此外, 基于光谱特征分析, 裂解温度还影响两种生物炭DOM诸多生物地球化学特征, 随着裂解温度上升, 两种生物炭DOM的相对分子质量, 芳香性、 疏水性和腐殖化程度均先增大再减小, 但对应的峰值温度各不一致。 因生物质原料差异, 楠竹生物炭DOM的相对分子质量, 芳香性、 疏水性和腐殖化程度均明显大于柏木生物炭。 该研究结论将进一步为生物炭DOM的环境行为研究, 生物炭应用过程中环境管理与评估提供有益的参考。

The dissolved organic matter (DOM) released from biochar has complex biogeochemical characteristics, affecting the migration and transformation of pollutants, carbon cycle and many other environmental processes. Compared with researches on the physicochemical and structural characteristics of biochar, researches on biochar DOM are few. The spectral characteristics of DOM released by biochar driven by pyrolysis temperature are rarely reported. We choose cypress and bamboo biochar, which are common and have a good application prospect, as research object. Spectral characteristics of DOM released from two kinds of biochar under different pyrolysis temperature (100~700 ℃) were identified by ultraviolet-visible spectra, and three-dimensional fluorescence spectra combined with parallel factor method (3DEEMs-PARAFACA). The results show that the pyrolysis temperature determines the DOM release potential and spectral characteristics of biochar. The amount of DOM decreases when the pyrolysis temperature increase and 400℃ is the critical temperature. When the pyrolysis temperature is lower than 400 ℃, the biochar DOM is obviously released; but the release amount of DOM is low and tends to be stable when the pyrolysis temperature is lower than 400 ℃. The amount of DOM released from cypress biochar is apparently higher than bamboo biochar. During the pyrolysis process at low temperature (<300 ℃), a large number of UV-visible chromophore exists in the DOM of biochar, which decomposes gradually with the increase of pyrolysis temperature. We isolated two humic-like fluorescent components (C1 and C2) and one protein-like fluorescence component (C3) from the fluorescent dissolved organic matter (FDOM) by 3DEEMs-PARAFAC. Three components show different responses to pyrolysis temperature, humic-like components appeared fluorescent intensity peak at 300 ℃, and then decrease when the temperature rises. Meanwhile, the fluorescent intensity of protein-like component decrease from beginning to end. FDOM under low pyrolysis temperature (＜200 ℃) is dominated by protein-like substance, but humic-like substance predominated when pyrolysis temperature increase. In addition, pyrolysis temperature also affects many biogeochemical characteristics of two kinds of biochar. With the increase of temperature, the relative molecular weight, aromaticity, hydrophobicity and humification degree firstly increase and then decrease, but the peak appears in different temperature. Due to the differences in raw materials, the relative molecular weight, aromaticity, hydrophobicity and humification degree of bamboo biochar was significantly higher than that of cypress. The conclusion of this study further provides beneficial references for the study on the environmental behavior of biochar DOM and the environmental management and assessment in the engineering application of biochar.