Yang Xinyu, Mu Yan, Zhang Lina, Sun Dan, Jian Tiantian, Tian Weiliang
Engineering Laboratory of Chemical Resources Utilization in South Xinjiang of Xinjiang Production and Construction Corps, College of Chemistry and Chemical Engineering, Tarim University, Alar 843300, China.
Instrumental Analysis Center of Tarim University, Alar 843300, China.
Materials (Basel). 2025 Jun 20;18(13):2930. doi: 10.3390/ma18132930.
In order to develop an efficient, environmentally friendly heavy metal ions adsorbent, the amino-modified expanded vermiculite-supported nano zero-valent iron (nZVI@PEI/EVMT) was prepared by using polyethyleneimine (PEI) as the functional reagent and expanded vermiculite (EVMT) as the carrier. The characterization results of nZVI@PEI/EVMT confirm that the PEI modification did not destroy the crystal configuration of EVMT, and when nano zero-valent iron (nZVI) was successfully loaded onto the PEI/EVMT surface, the value of saturation magnetic field was 41.5 emu/g, which could be separated from solution with magnet. The performance of Cr(VI) adsorption onto nZVI@PEI/EVMT was studied, showing that the ideal mass ratio for nZVI@PEI/EVMT was 1:1, and the removal capacity was largest when solution pH was 2. After four adsorption-desorption cycles, the adsorption amounts remained 40.1 mg/g. The Cr(VI) adsorption onto nZVI@PEI/EVMT was more consistent with a pseudo-second-order kinetics equation. Isotherm adsorption data accord with the Langmuir model, which suggests that the adsorption was the monolayer, the maximum adsorption amount was 116.2 mg/g at 30 °C and pH 2, and the adsorption was spontaneous and endothermic. It was inferred that the adsorption mechanisms included electrostatic attraction, reduction, chemical complexation, and co-precipitation.
为了开发一种高效、环保的重金属离子吸附剂，以聚乙烯亚胺（PEI）为功能试剂、膨胀蛭石（EVMT）为载体，制备了氨基改性膨胀蛭石负载纳米零价铁（nZVI@PEI/EVMT）。nZVI@PEI/EVMT的表征结果证实，PEI改性并未破坏EVMT的晶体结构，当纳米零价铁（nZVI）成功负载到PEI/EVMT表面时，饱和磁场值为41.5 emu/g，可用磁铁从溶液中分离。研究了nZVI@PEI/EVMT对Cr(VI)的吸附性能，结果表明nZVI@PEI/EVMT的理想质量比为1:1，溶液pH为2时去除能力最大。经过4次吸附-解吸循环后，吸附量仍为40.1 mg/g。nZVI@PEI/EVMT对Cr(VI)的吸附更符合准二级动力学方程。等温吸附数据符合Langmuir模型，表明吸附为单层吸附，30℃、pH为2时最大吸附量为116.2 mg/g，吸附是自发的且吸热的。推断吸附机制包括静电吸引、还原、化学络合和共沉淀。
