摘要
为寻求高效、廉价的E2(雌二醇激素)吸附剂及开拓蚯蚓粪便的资源化利用途径,将蚯蚓粪便在300、500和700℃下热解碳化制备生物炭(分别记为BC300、BC500和BC700),对所得生物炭的基本理化性质(包括物质组成、表面官能团、孔隙结构等)进行分析,并将其用于吸附水体中E2,考察生物炭投加量、溶液p H、反应时间及初始ρ(E2)对生物炭吸附性能的影响,并探讨了吸附机理.结果表明:随热解温度的升高,生物炭的H/C(原子比)由0.13降至0.03,O/C(原子比)由0.46降至0.02,芳香性增强,极性降低,逐渐由脂肪炭结构过渡到芳香炭结构;生物炭比表面积由24.33 m2/g增至76.29 m2/g,总孔体积由0.09 cm3/g增至0.19 cm3/g.不同热解温度下制备的生物炭对E2的吸附过程均符合准二级动力学方程,拟合系数大于0.991;Langmuir和Freundlich等温吸附模型均能较好地描述蚯蚓粪便生物炭对E2的吸附过程,Langmuir理论最大吸附量表现为BC700(7.66 mg/g)>BC500(5.23 mg/g)>BC300(3.32 mg/g).随热解温度的升高,O/C和H/C降低,说明碳化程度增强,生物炭吸附E2的分配作用减弱而表面吸附作用增强.研究显示,蚯蚓粪便生物炭对E2的吸附效果随比表面积和孔体积的增加而增强.
In order to find an efficient and low-cost adsorbent to remove 17β-estradiol（ E2） from aqueous solutions as well as explore a resource utilization method of vermicompost,vermicompost-derived biochars（ BC300,BC500 and BC700） were prepared by pyrolyzing vermicompost at temperatures of 300,500 and 700 ℃,respectively. The physicochemical properties,including elemental compositions,surface functional groups and pore structures of the biochars were analyzed. Batch adsorption of E2 was conducted to explore the effects of adsorbent dosage,p H,equilibrium time and initial E2 concentrations on adsorption,and the adsorption mechanisms were discussed as well. The results showed that H/C and O/C of the biochars decreased with increasing pyrolysis temperature,which indicated the increase of aromaticity. On the contrary,the surface area and the total pore volume of the biochar increased with increasing pyrolysis temperature.Adsorption processes could be well fitted by the pseudo second order equation（ R2 0. 991）. Both the Langmuir and Freundlich models could properly fit the adsorption isotherm. The maximum adsorption capacities of BC700,BC500 and BC300 predicted by the Langmuir model were 7. 66,5. 23 and 3. 32 mg/g,respectively. With the decrease of O/C and H/C,the carbonization of biochar increased,so that the contribution of partition to adsorption decreased while the contribution of surface adsorption increased. In addition, the adsorption capacity was positively correlated with the relationship with the specific surface area and pore volume of biochars.
出处
《环境科学研究》
EI
CAS
CSSCI
CSCD
北大核心
2016年第10期1537-1545,共9页
Research of Environmental Sciences
基金
四川省科技支撑计划项目(2014NZ0045
2015SZ0007)
国家自然科学基金项目(21306120)
关键词
蚯蚓粪便
生物炭
热解温度
吸附
雌二醇
vermicompost
biochar
pyrolysis temperature
adsorption
17β-estradiol
