基于光谱色谱分析热解温度对沼渣生物炭DOM组成特性的影响

为探究沼渣基生物炭溶解性有机质（DOM）的组成特性，以厌氧发酵沼渣为原料，在300、400、500、600和700℃热解温度下制备了生物炭，利用紫外-可见光谱、三维荧光光谱以及反相高效液相色谱等手段，研究了生物炭中DOM的组成特性.结果表明:热解温度影响生物炭DOM的组成，随着热解温度的升高，生物炭DOM中溶解性有机碳含量出现大幅降低，由300℃时的33.2 mg/g降至700℃时的0.7 mg/g.生物炭DOM的芳香性和分子量呈先增后减的变化趋势，400℃时其芳香性和分子量最大；在300~500℃热解范围内，生物炭DOM主要与类腐殖质有关，在600~700℃热解温度范围内，生物炭DOM主要是类色氨酸物质；液相色谱分析显示，在254 nm波长处洗脱出4种芳香物质，280 nm波长处洗脱出5种醌基物质，其中4种醌基结构物质赋存在芳香结构中.研究显示，沼渣生物炭DOM的组成与热解温度密切相关，不同的热解温度会影响DOM的芳香性、分子特性、腐殖化程度、亲水性及极性等特征，光谱和色谱分析法可有效表征DOM的不同结构性质. 

Effect of Pyrolysis Temperature on Composition Characteristics of DOM of Biogas Residue Biochar Based on Spectral and Chromatographic Analysis

In order to explore the dissolved organic matter (DOM) in the biogas residue, it was pyrolyzed at various temperatures (300, 400, 500, 600 and 700℃) to prepare various biochar samples. The raw material was the biogas residue from an anaerobic fermentation plant. The DOM composition characteristics of the biochars were analyzed using UV-Vis spectroscopy, three-dimensional fluorescence spectroscopy, and reversed-phase high performance liquid chromatography. The results showed that the pyrolysis temperature affected the composition of biochar DOM. The w(DOC) in biochar DOM decreased with the increase of pyrolysis temperature. The w(DOC) decreased from 33.2 mg/g at 300℃ to 0.7 mg/g at 700℃. As the temperature increased the aromaticity and molecular weight of biochar DOM first increased and then gradually decreased; the aromaticity and molecular weight were the largest at 400℃. In the pyrolysis range of 300-500℃, the biochar DOM was mainly related to humic-like substances, and when the pyrolysis range was 600-700℃, the biochar DOM was mainly tryptophan-like substances. Liquid chromatography analysis showed that four kinds of aromatic substances and five kinds of quinone-based substances were eluted at the wavelength of 254 and 280 nm. This shows that the biochar contained four kinds of quinone-based structural substances. Therefore, the composition of biogas residue biochar DOM was closely related to the pyrolysis temperature. Different pyrolysis temperatures affected the aromaticity, molecular characteristics, humification degree, hydrophilicity, and polarity of DOM. The spectroscopy and chromatography can effectively characterize different structural properties of DOM.