生物炭和乙醇改性生物炭对铜的吸附研究  

Comparison of copper adsorption onto wheat biochar and ethanol-modified biochar

作　　者：尹英杰 朱司航 徐东昊[1] 楚龙港 陈冲[1,2,3] 赵晶晶[1,2,3] 商建英 

机构地区：[1]中国农业大学资源与环境学院,北京100193 [2]教育部植物-土壤相互作用重点实验室,北京100193 [3]农业部华北耕地保育重点实验室,北京100193

出　　处：《农业环境科学学报》2017年第9期1877-1883,共7页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(41501232);国家级创新训练项目(201610019027)~~

摘　　要：为研究生物炭和乙醇改性生物炭的特性及其对铜的吸附能力,选取小麦秸秆为原料,在300、450、600℃条件下热解制备生物炭,用于研究乙醇改性生物炭的产油率、生物炭和乙醇改性生物炭的表面官能团变化、亲水性能及其对Cu^(2+)的吸附特性。结果表明:乙醇改性生物炭产油率随热解温度升高而增加。生物炭和乙醇改性生物炭不同温度接触角范围为122.6°~89.3°和96.0°~68.7°,乙醇改性生物炭亲水性明显高于未经改性生物炭。生物炭和改性生物炭对Cu^(2+)的吸附符合二级动力学模型,生物炭吸附速率常数达1.535 g·mg^(-1)·h^(-1),乙醇改性生物炭为1.073 g·mg^(-1)·h^(-1)。二者对Cu^(2+)的等温吸附过程符合Langmuir等温吸附模型,生物炭和乙醇改性生物炭最大吸附量分别为44.3 mg·g-1和41.7 mg·g-1,说明使用乙醇萃取生物炭生物质油后,仍能保持90%左右的Cu^(2+)吸附效率。To test the performance of biochar with and without bio-oil for the removal of heavy metals, wheat straw biochars pyrolyzed at three temperatures（300 ℃, 450 ℃, and 600 ℃）were used and then modified by ethanol solution. The ethanol-modified biochars were prepared in 75% ethanol solution for 12 hours to remove bio-oils from the biochars. The characteristics of the raw and ethanol-modified biochars were analyzed, and batch and kinetic adsorption experiments were conducted. The results showed that more bio-oil production rate was obtained using the ethanol-modified biochar pyrolyzed at higher temperature. The contact angle ranges of the raw and ethanol-modified biochars with water were from 122.6° to 89.3° and from 96.0° to 68.7°, respectively, which meant that the ethanol-modified biochars showed less hydrophobicity than the raw biochars did. Ethanol modification had almost no effect on the adsorption rate of the biochar pyrolyzed at300 ℃, and decreased the adsorption rate of the raw biochar pyrolyzed at 600 ℃ by 30%, from 1.535 g·mg^-1·h^-1to 1.073 g·mg^-1·h^-1.Ethanol modification only slightly decreased the maximum adsorption capacity of the biochars pyrolyzed at all three temperatures, as the biochar modified with ethanol still had around 90% adsorption capacity of the biochars without ethanol modification. The copper adsorption processes onto the raw and ethanol-modified biochars were well fitted by second-order kinetics and Langmuir adsorption models.

关 键 词：小麦秸秆 生物炭 CU2+ 吸附平衡 接触角 

分 类 号：X712[环境科学与工程—环境工程]