Zhang Ru-Yu, Liu Hai-Bo, Zou Xue-Hua, Qing Cheng-Song, Li Meng-Xue, Chen Dong, Chen Tian-Hu
School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
Huan Jing Ke Xue. 2017 Aug 8;38(8):3519-3528. doi: 10.13227/j.hjkx.201612156.
C-FeO composite material [magnetic biomass char (MBC)] was prepared by pyrolysis of a mixture of wheat straw and siderite at 500℃. The MBC was characterized by XRF, FTIR, XRD, SEM, XPS, and a magnetic susceptibility device. The effect of contact time, pH value, initial Cd concentration, and ionic strength on the adsorption capacity of the MBC to Cd was investigated. The results showed that the BET surface areas of the MBC and biomass char (BC) were 23.38 m·g and 7.20 m·g, respectively, total pore volumes were 1.04×10 cm·g and 2.23×10 cm·g, and average pore diameters were 17.74 nm and 12.38 nm. The magnetic susceptibility of the MBC was 42900×10 m·kg. FTIR showed that phenolic hydroxyl and carboxyl functional groups bound metal ions on the surface of the MBC and BC. The kinetic data of the MBC were described well by the pseudo-second-order model. Isothermal adsorption of Cd by MBC and BC was fitted well by the Freundlich equation. The adsorption velocity increased with an increase of pH in the region 3-6 and then stabilized in the region 6-9. The adsorption capacity of Cd decreased slightly when ionic strength increased from 1 mmol·L to 100 mmol·L, whereas the desorption rate increased from 0.51% to 8.5%. The adsorption properties and characterization results illustrated that the removal mechanism of Cd likely was through adsorption and ion exchange on the surface of the MBC with a high amount of functional groups. In addition, magnetic adsorbents offered a significant advantage compared to other adsorbents in the aspect of separation from aqueous solution.
通过在500℃下热解小麦秸秆和菱铁矿的混合物制备了C-FeO复合材料[磁性生物质炭（MBC）]。采用XRF、FTIR、XRD、SEM、XPS和磁化率仪对MBC进行了表征。研究了接触时间、pH值、初始镉浓度和离子强度对MBC吸附镉能力的影响。结果表明，MBC和生物质炭（BC）的BET表面积分别为23.38 m²·g和7.20 m²·g，总孔容分别为1.04×10⁻² cm³·g和2.23×10⁻² cm³·g，平均孔径分别为17.74 nm和12.38 nm。MBC的磁化率为42900×10⁻⁶ m³·kg。FTIR表明，酚羟基和羧基官能团在MBC和BC表面结合金属离子。伪二级模型能很好地描述MBC的动力学数据。MBC和BC对镉的等温吸附符合Freundlich方程。在3-6区域内，吸附速度随pH值升高而增加，在6-9区域内趋于稳定。当离子强度从1 mmol·L增加到100 mmol·L时，镉的吸附量略有下降，而解吸率从0.51%增加到8.5%。吸附性能和表征结果表明，镉的去除机制可能是通过MBC表面大量官能团的吸附和离子交换。此外，磁性吸附剂在从水溶液中分离方面比其他吸附剂具有显著优势。
