秸秆生物质炭DOM光谱特征及其与Cu2+的相互作用

通过荧光猝灭滴定法探究玉米秸秆炭（MSB）、水稻秸秆炭（RSB）和花生秸秆炭（PSB）中DOM的光谱特征及其与Cu²⁺的络合机理.结果表明：三种生物质炭的DOM均具有较高的亲水性和较低的芳香性，其中RSB-DOM的芳香性相对较强、分子量较大，但DOM含量低，PSB-DOM含量最高，芳香结构中含氧官能团较多.MSB和RSB-DOM中均含类富里酸组分C1和类腐殖酸组分C3、C4，RSB-DOM中还有类色氨酸组分C5，PSB-DOM则由两种类富里酸组分C1、C2和较长波长类腐殖酸组分C4组成，3种DOM均以类富里酸组分为主，占比达54.93%~86.29%.Cu²⁺与类腐殖酸组分的稳定常数（logK_M）高于类富里酸组分，且类腐殖酸组分C4的络合能力（f）最强，类腐殖酸组分的logK_M和f值总体上表现为：PSB-DOM> MSB-DOM>RSB-DOM.二维相关光谱分析发现，类富里酸组分对Cu²⁺最敏感，而Cu²⁺优先与类腐殖酸组分结合.研究结果有助于进一步揭示生物质炭的DOM对Cu²⁺环境行为的影响机制.

DOM spectral characteristics of straw biochar and its interaction with Cu2+

Fluorescence quenching titration was used to explore the spectral characteristics of DOM in maize straw biochar (MSB), rice straw biochar (RSB) and peanut straw biochar (PSB), and their complexation mechanism with Cu²⁺. The results showed that the DOM in biochar had higher hydrophilicity and lower aromatability. RSB-DOM had relatively strong aromatability, higher molecular weight and lower DOM content. DOM of PSB had more oxygen-containing functional groups in the aromatic structure. Fulvic acid-like component C1and humic acid-like component C3 and C4 were found in MSB-DOM and RSB-DOM, and tryptophan-like component C5 in RSB-DOM. PSB-DOM was composed of two kinds of fulvic acid-like components C1 and C2 and humic acid-like component C4 with longer wavelength. DOM were dominated by fulvic acid-like components, accounting for 54.93~86.29%. The stability constant (logK_M) of Cu²⁺ and humic acid-like component was higher than that of fulvic acid-like component, and the complexation capacity (f) of C4 was the strongest. The logK_M and f values of humic acid-like component were as follows:PSB-DOM2+, and Cu²⁺ preferred to bind to the humic acid component. This study are helpful to further reveal the influence mechanism of DOM of biochar on the environmental behavior of Cu²⁺.