空心莲子草浸提液对两性紫色土重金属离子选择性吸附的作用机制。
Effect mechanism of litter extract from Alternanthera philoxeroides on the selective absorption of heavy metal ions by amphoteric purple soil.
机构信息
College of Environmental Science and Engineering, China West Normal University, Nanchong, Sichuan, 637009, China.
College of Environmental Science and Engineering, China West Normal University, Nanchong, Sichuan, 637009, China.
出版信息
J Environ Manage. 2022 Nov 1;321:115970. doi: 10.1016/j.jenvman.2022.115970. Epub 2022 Aug 12.
Plant litter causes a serious waste of resources. Thus, plant litter extract (LE) should be used in the soil remediation of heavy metals. In this study, different proportions of LE from the Alternanthera philoxeroides were used to modify dodecyl dimethyl betaine (BS)-modified purple soil (P). The basic physicochemical properties of LE + BS-modified Ps (LE + BS-Ps) were determined, and the microscopic morphology of LE + BS-Ps was studied by using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and specific surface area detection. The isothermal adsorption characteristics of heavy metal ions (Pb, Cu, and Cr) on different LE + BS-Ps were investigated by the batch method, and the effect mechanisms of temperature, pH, ionic strength, and LE + BS-P's property were compared. Results showed that the cation exchange capacity and specific surface area of LE + BS-Ps increased, pH of LE + BS-Ps decreased, and TOC of LE + BS-Ps increased first and then decreased with increasing proportion of LE. FTIR, SEM, and EDS results proved that LE was modified on the surface of BS-P. Langmuir and Freundlich models could be used to describe the adsorption isotherms of heavy metal ions on different LE + BS-Ps, and the fitting correlation of the Langmuir model was higher than that of the Freundlich model. The maximum adsorption capacity (q) of Pb, Cu, and Cr were 107.60-295.66, 133.00-342.11, and 33.59-75.41 mmol/kg, respectively. The q of Pb, Cu, and Cr on LE + BS-Ps all increased first and then decreased with increasing proportion of LE, and the peak value was observed in 20%LE + BS-Ps. High pH improved Pb and Cu adsorption but inhibited Cr adsorption. The adsorption amounts of Pb, Cu, and Cr all increased first and then decreased with incresing ionic strength and were maintained at the maximum value of 0.1-0.2 mol/L. The Pb, Cu, and Cr adsorption mechanisms on different LE + BS-Ps showed a positive temperature effect and presented spontaneous, exothermic and entropy-adding processes.
植物凋落物造成了严重的资源浪费。因此，植物凋落物提取物（LE）应该被用于重金属的土壤修复。在这项研究中，不同比例的水花生 LE 被用来修饰十二烷基二甲基甜菜碱（BS）修饰的紫色土壤（P）。测定了 LE+BS 修饰的 Ps（LE+BS-Ps）的基本物理化学性质，并通过扫描电子显微镜（SEM）、能量色散光谱（EDS）、傅里叶变换红外（FTIR）光谱和比表面积检测研究了 LE+BS-Ps 的微观形貌。采用批量法研究了不同 LE+BS-Ps 对重金属离子（Pb、Cu 和 Cr）的等温吸附特性，并比较了温度、pH 值、离子强度和 LE+BS-P 性质的影响机制。结果表明，LE+BS-Ps 的阳离子交换容量和比表面积增加，pH 值降低，而 LE+BS-Ps 的 TOC 先增加后减少，随着 LE 比例的增加而增加。FTIR、SEM 和 EDS 结果证明 LE 被修饰在 BS-P 的表面上。Langmuir 和 Freundlich 模型可用于描述重金属离子在不同 LE+BS-Ps 上的吸附等温线，Langmuir 模型的拟合相关性高于 Freundlich 模型。Pb、Cu 和 Cr 的最大吸附容量（q）分别为 107.60-295.66、133.00-342.11 和 33.59-75.41 mmol/kg。Pb、Cu 和 Cr 在 LE+BS-Ps 上的 q 随 LE 比例的增加先增加后减少，在 20%LE+BS-Ps 时达到峰值。高 pH 值提高了 Pb 和 Cu 的吸附，但抑制了 Cr 的吸附。随着离子强度的增加，Pb、Cu 和 Cr 的吸附量先增加后减少，并在 0.1-0.2 mol/L 时保持最大。不同 LE+BS-Ps 上 Pb、Cu 和 Cr 的吸附机制表现出正温度效应，呈现自发、放热和熵增加的过程。
Zotero 插件