Yamada Kazunori, Ishiguro Yohei, Kimura Yuji, Asamoto Hiromichi, Minamisawa Hiroaki
a Department of Applied Molecular Chemistry , College of Industrial Technology, Nihon University , Narashino , Japan.
b Department of Basic Science , College of Industrial Technology, Nihon University , Narashino , Japan.
Environ Technol. 2019 Mar;40(7):855-869. doi: 10.1080/09593330.2017.1409274. Epub 2017 Dec 7.
Polyethylene (PE) plates grafted with a neutral monomer, 2-hydroxyethyl methacrylate (HEMA), and a cationic monomer, 2-(dimethylamino)ethyl methacrylate (DMAEMA), (PE-g-PHEMA)-g-PDMAEMA plates were prepared by the two-step photografting. The Cr(VI) ion adsorption behavior of the (PE-g-PHEMA)-g-PDMAEMA plates was investigated as a function of the amounts of grafted HEMA, amount of grafted DMAEMA, initial pH value, and temperature. The adsorption capacity of the DMAEMA-grafted PE (PE-g-PDMAEMA) and (PE-g-PHEMA)-g-PDMAEMA plates had the maximum value at the initial pH value of 3.0, independent of the temperature. The adsorption capacity of (PE-g-PHEMA)-g-PDMAEMA plates increased with the amount of grafted HEMA (G) in the first-step grafting. The increase in the water absorptivity of the grafted layers and thereby the increase in the degree of protonation of dimethylamino groups on grafted PDMAEMA chains were found to lead to the increase in the adsorption capacity. This adsorption capacity was higher than or comparable to those of other polymeric adsorbents for Cr(VI) ions. The Cr(VI) ion adsorption behavior on both PE-g-DMAEMA and (PE-g-PHEMA)-g-PDMAEMA plates obeyed the mechanism of the pseudo-second-order kinetic model and was well expressed by Langmuir isotherm. The high values of the Langmuir constant suggest that the adsorption of Cr(VI) ions occurs through an electrostatic interaction between protonated dimethylamino groups on grafted PDMAEMA chains and ions. Cr(VI) ions were successfully desorbed from PE-g-PDMAEMA and (PE-g-PHEMA)-g-PDMAEMA plates in eluents such as NaCl, NaCl containing NaOH, NHCl, NHCl containing NaOH, and NaOH.
通过两步光接枝法制备了接枝有中性单体甲基丙烯酸2 - 羟乙酯（HEMA）和阳离子单体甲基丙烯酸2 -（二甲氨基）乙酯（DMAEMA）的聚乙烯（PE）板，即（PE - g - PHEMA）- g - PDMAEMA板。研究了（PE - g - PHEMA）- g - PDMAEMA板对Cr(VI)离子的吸附行为，考察了接枝HEMA的量、接枝DMAEMA的量、初始pH值和温度的影响。DMAEMA接枝的PE（PE - g - PDMAEMA）和（PE - g - PHEMA）- g - PDMAEMA板的吸附容量在初始pH值为3.0时达到最大值，与温度无关。（PE - g - PHEMA）- g - PDMAEMA板的吸附容量随第一步接枝中接枝HEMA的量（G）增加而增加。发现接枝层吸水性的增加以及接枝PDMAEMA链上二甲氨基质子化程度的增加导致吸附容量增加。该吸附容量高于或与其他用于Cr(VI)离子的聚合物吸附剂相当。PE - g - DMAEMA和（PE - g - PHEMA）- g - PDMAEMA板上Cr(VI)离子的吸附行为均符合准二级动力学模型机制，并用Langmuir等温线很好地表示。Langmuir常数的高值表明Cr(VI)离子的吸附是通过接枝PDMAEMA链上质子化的二甲氨基与离子之间的静电相互作用发生的。Cr(VI)离子在NaCl、含NaOH的NaCl、NHCl、含NaOH的NHCl和NaOH等洗脱剂中成功地从PE - g - PDMAEMA和（PE - g - PHEMA）- g - PDMAEMA板上解吸。
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