Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Biomass Engineering Center, China Agricultural University, Beijing 100193, China.
Bioresour Technol. 2018 Jan;247:370-379. doi: 10.1016/j.biortech.2017.09.107. Epub 2017 Sep 20.
An adsorbent hydrochar was synthesized from corn cobs and modified with polyethylene imine (PEI). The hydrochars before and after modification were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. FTIR and XPS revealed that the PEI was grafted onto the hydrochar via ether and imine bonds formed with glutaraldehyde. The maximum adsorption capacities for Cr(VI) (33.663mg/g) and Ni(II) (29.059mg/g) on the modified hydrochars were 365% and 43.7% higher, respectively, than those on the unmodified hydrochar. A pseudo-second-order model described the adsorption of Ni(II) and Cr(VI) on all the adsorbents. The adsorption of Cr(VI) was endothermic, spontaneous, increased disorder, and obeyed the Langmuir model. By contrast, the adsorption of Ni(II) was exothermic, spontaneous, decreased disorder, and obeyed the Freundlich model. XPS confirmed that the adsorption sites and mechanisms for Ni(II) and Cr(VI) on the modified hydrochars were different.
一种吸附水炭由玉米芯合成，并经过聚乙烯亚胺（PEI）修饰。修饰前后的水炭通过扫描电子显微镜、傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）和热重分析进行了表征。FTIR 和 XPS 表明，PEI 通过与戊二醛形成的醚键和亚胺键接枝到水炭上。修饰后的水炭对 Cr(VI)（33.663mg/g）和 Ni(II)（29.059mg/g）的最大吸附容量分别比未修饰的水炭高 365%和 43.7%。拟二级动力学模型描述了 Ni(II)和 Cr(VI)在所有吸附剂上的吸附。Cr(VI)的吸附是吸热、自发、增加无序的，并遵循朗缪尔模型。相比之下，Ni(II)的吸附是放热、自发、降低无序的，并遵循弗雷德里希模型。XPS 证实了修饰后的水炭对 Ni(II)和 Cr(VI)的吸附位点和机制不同。
