中文摘要：

生物炭对污染物的吸附是生物炭环境效应研究的重要环节,而生物炭中的自由基对有机污染物降解行为的影响还没有得到应有的关注。以水稻秸秆为原材料,研究不同热解温度下制备的生物炭对罗丹明B的吸附和降解,通过荧光光谱法分析生物炭-罗丹明B体系反应前后上清液荧光光谱特性的变化来表征其中的降解现象。结果表明,在350℃和500℃生物炭-罗丹明B反应体系中,其上清液荧光光谱明显发生蓝移现象,表明该体系中存在着明显的降解现象。通过对这2个体系反应后生物炭固体颗粒的萃取来对降解作用进行定量分析,降解作用在这2个体系中所占的比例分别为28%和30%。水稻秸秆生物质炭对罗丹明B具有较好的吸附效果,Freundlich方程可以较好地描述水稻秸秆生物质炭对水中罗丹明B的吸附行为,固液比在3∶1 000时生物炭最大吸附量为3.33 mg·g^-1。这表明在水稻秸秆生物炭-罗丹明B反应体系中,不仅存在吸附作用,还伴随降解作用。

英文摘要：

Biochars have attracted international research attention because of their wide application potential,including their high sorption to organic contaminants,which will benefit pollutant control. In biochar sorption studies,investigators generally ignored the interactions between organic contaminants and free radicals in biochars.Thus,the behavior of organic contaminants was not fully understood in the presence of biochars. This study used rice straw to produce biochars. The interactions between biochars and rhodamine B were investigated with the emphasis of identifying sorption and degradation. When analyzing rhodamine B in the solution using fluorescence spectrometer,blue shift of the absorbance was clearly observed in the presence of biochars. This phenomenon suggested significant chemical alteration of rhodamine B molecules. Through the organic solvent extraction of the solid particles,the real sorption could be quantified. In the common sorption experimental design,degradation accounted for 28% and 30% of the apparently decreased aqueous-phase concentration. Rhodamin B degradation could be calculated through mass balance calculation. The Freundlich equation can describe well the adsorption behavior of rice straw biomass carbon on rhodamine B in water,and the maximum adsorption capacity of biochar is 3. 33 mg·g^-1at 3 ∶ 1 000. This study calls the readers＇ attention that free radicals in biochars should be carefully evaluated for their environmental roles,especially for the fate of organic contaminants.