• 关键词：溶解性生物炭  裂解温度  光敏化  活性氧自由基  构-效关系

• 基金项目：国家自然科学基金（No. 42107035， 21976158）；国家重点研发计划（No.2018YFE0110500）

• 魏亚俊
• 浙江工商大学环境与工程学院，杭州 310018

• 刘婧妍
• 浙江工商大学环境与工程学院，杭州 310018

• 陈再明
• 浙江工商大学环境与工程学院，杭州 310018

• 汪美贞
• 浙江工商大学环境与工程学院，杭州 310018

• 方婧
• 浙江科技学院环境与资源学院，杭州 310023

• 黄丹
• 浙江工商大学环境与工程学院，杭州 310018

• 冯华军
• 浙江工商大学环境与工程学院，杭州 310018

• 摘要：溶解性生物炭受紫外光辐射产生的活性氧自由基（Reactive oxygen species， ROS）易对环境造成影响，受到环境领域的持续关注.以玉米秸秆为原料，在不同裂解温度（200~600 ℃）下制备了5种生物炭，并通过水提得到溶解性生物炭（Dissolved biochar， DBC），系统考察了生物炭裂解温度对DBC结构和组分的影响，并利用化学分子探针定量研究了DBC在紫外光辐射下产生常见ROS的能力，如羟基自由基（Hydroxyl radical， ?OH）、单线态氧（Singlet oxygen， ¹O₂）和超氧自由基（Superoxide radical， O₂?^-）.结果表明，DBC主要由有机酸、类蛋白质和纳米级生物炭构成，前两者皆会随生物炭裂解温度上升而减少，后者则会逐渐增多.高温DBC-（400~600 ℃）具有更强芳香性和疏水性，但荧光物质含量极低.对DBC产生的ROS进行定量研究发现，仅DBC-200 ℃和300 ℃产生少量?OH.DBC-300 ℃的¹O₂表观量子产率（Φ¹O₂）最多，为7.41%；DBC-400 ℃的O₂^?-表观量子产率（ΦO₂^?-）最多，为2.12%.DBC-300 ℃中荧光物质和腐殖酸类物质更多，羰基和醛醌类官能团比例最高，促进其产生更高的¹O₂含量；DBC-400 ℃芳香性结构丰富且更强，促进其产生更高的O₂^?-含量.DBC经长期紫外光辐照（168 h）后，芳香性降低，高分子量化合物减少，自身也会通过光矿化形式（约30%）参与碳循环.本文为阐明DBC自身光降解、光敏化ROS产能和组成结构间的构-效关系提供了理论依据，为DBC潜在的环境污染修复应用奠定了坚实基础.

• Abstract：Dissolved biochar can produce reactive oxygen species （ROS） under ultraviolet light， which has attracted continuous attention in the field of environmental science. In this study， five kinds of biochar were obtained by pyrolysis of corn stalk at different temperatures （200 ~ 600 ℃）， and the corresponding dissolved biochar （DBC） was obtained by water extraction. The effects of pyrolysis temperature on the structural properties and components of DBC were systematically investigated， and the ability of DBC to produce common ROS， such as hydroxyl radicals （?OH）， singlet oxygen （¹O₂） and superoxide radicals （O₂?^-） under ultraviolet light radiation was quantified with different chemical probes. The results show that DBC was mainly composed of humic-like substance， nano-biochar and proteinoid， of which both the contents of humic-like substance and nano-biochar were decreased with the increasing pyrolysis temperature of biochar， while the proteinoid content increased with the increasing pyrolysis temperature. The high-temperature （400~600 ℃） derived DBC had higher aromaticity and hydrophobicity， while very low fluorescent content. Moreover， only DBC at 200 ℃ and 300 ℃ produced small amounts of ?OH. DBC at 300 ℃ and 400 ℃ had the highest value of the apparent quantum yields of ¹O₂ （Φ¹O₂， 7.41%） and O₂?^-（ΦO₂?^-， 2.12%）， respectively. Over the long-term （168 h） ultraviolet light irradiation， the aromaticity and the content of high molecular weight compounds in DBC gradually decreased. Consequently， approximately 30% DBC participated in the carbon cycle through photomineralization. This study provides a theoretical basis for the self-photodegradation of DBC， and for the structure-property relationship between production and composition structure of photosensitized ROS， which lays a solid foundation for the potential application of DBC for environmental pollution remediation.

• Key words：dissolved biochar  pyrolysis temperature  photosensitization  reactive oxygen radicals  structure-property relationship

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