零价铁、铜改性生物炭及其对Cr(Ⅵ)吸附性能的影响

针对纳米零价铁（nanoscale zero valent iron，nZVI）易团聚的特性，本文用鸡骨生物炭（BC）作载体，制备出生物炭-零价铁（Fe-BC）去除Cr(Ⅵ)，并与铜改性的生物炭-零价铁（Fe-Cu-BC）和BC对Cr(Ⅵ)的吸附性能进行了对比。通过扫描电镜（SEM）和能谱仪（EDS）、X射线衍射（XRD）、N₂吸脱附等温线和傅里叶红外光谱（FTIR）对材料表面形貌及结构性质进行分析，同时考察了溶液pH、接触时间等条件对吸附剂吸附容量的影响，通过吸附动力学和吸附等温线分析了吸附特性。结果表明，在pH=2的条件下去除Cr(Ⅵ)效果较好；吸附平衡遵从Langmuir吸附等温式；吸附动力学符合准二级动力学方程。Fe-BC材料吸附水体污染物后可用磁分离技术加以回收。Fe-Cu-BC缩短了对Cr(Ⅵ)的吸附平衡时间。制备出的吸附剂对Cr(Ⅵ)的理论最大吸附量顺序为 Fe-BC>Fe-Cu-BC>BC；同时， Fe-BC吸附量为153.60mg/g，对比于先前报道的nZVI对Cr(Ⅵ)的吸附容量85mg/g左右，有了很大的提升，说明BC作载体成功解决了nZVI易团聚的缺点，拓展了实际应用。

Influence of zero valent iron and copper modified biochar on Cr(Ⅵ) adsorption

In view of the easy-agglomeration of nanoscale zerovalent iron (nZVI), chicken bone biochar (BC) supported nZVI(Fe-BC) and copper-modified biochar(BC) supported nZVI (Fe-Cu-BC) to remove chromium(). The adsorption properties of Cr() by Fe-Cu-BC, Fe-BC and BC were compared. The physicochemical properties of materials were characterized by SEM, EDS, XRD, N₂ adsorption isotherm and FTIR. Batch adsorption experiments were conducted to investigate the effects of pH and contact time on the Cr() adsorption. The adsorption characteristics were analyzed by adsorption kinetics and isotherms. Results showed that the removal of Cr() was better at pH=2; the process was better described by the Langmuir isotherm model; and the adsorption process was consistent with the pseudo-second-order model. The Fe-BC materials could be recovered by magnetic separation technique after adsorbing water pollutants. Fe-Cu-BC shortened the adsorption equilibrium time for Cr().The theoretical maximum adsorption on Cr() showed following order: Fe-BC>Fe-Cu-BC>BC.The Cr() adsorption amount by Fe-BC was 153.60mg/g, which showed great improvement compared with the previously reported 85mg/g by zerovalent iron. It indicated that biochar as a carrier successfully addressed the easy-agglomeration shortcomings of zerovalent iron and expanded the practical application.