Department of Polymers and Pigments, National Research Centre, Dokki 12622, Cairo, Egypt.
Department of Chemistry, Faculty of Science, Al- Azhar University, Nasr City, Cairo, Egypt.
Int J Biol Macromol. 2017 Oct;103:261-267. doi: 10.1016/j.ijbiomac.2017.05.052. Epub 2017 May 16.
A specially-designed graft copolymer of acrylic acid onto in-situ formed cellulose-fulvate hybrid showed privileged tendency for uptake of Pb(II) during competitive removal from a mixture containing Cd(II) and Ni(II) within 5min at pH 5. This novel trend is attributed mainly to the crowded high content of coordinating centers within the designed graft copolymer along with the acquired superabsorbency. This provides an outstanding tool to separate some metal ions selectively from mixtures containing multiple ions on kinetic basis. Thus, the designed graft copolymer structure exhibited superior efficiency that reached ∼95% for sole removal of Pb(II). Kinetic modeling for Pb(II) individual removal showed excellent fitting with a pseudo second-order model. Intraparticle diffusion model on the other hand ensured governance of boundary layer effect over diffusion during the removal process due to the superabsorbency feature of the graft copolymer. The experimental findings were described with models such as Freundlich, Langmuir, and Dubinin-Radushkevich. The Langmuir and Freundlich models showed convenience with the adsorption isotherm of Pb(II) onto the developed graft copolymer.
一种特制的接枝共聚物，将丙烯酸接枝到原位形成的纤维素-富马酸杂化体上，在 pH 值为 5 的条件下，从含有 Cd(II)和 Ni(II)的混合物中，在 5 分钟内优先表现出对 Pb(II)的吸收倾向。这种新趋势主要归因于设计的接枝共聚物中高含量的配位中心以及获得的超吸收能力。这为基于动力学从含有多种离子的混合物中选择性分离一些金属离子提供了一种出色的工具。因此，设计的接枝共聚物结构表现出优异的效率，对单独去除 Pb(II)的去除率达到约 95%。对 Pb(II)单独去除的动力学模型拟合非常好，符合拟二级模型。另一方面，由于接枝共聚物的高吸收能力，内扩散模型确保了在去除过程中边界层效应对扩散的控制。实验结果用 Freundlich、Langmuir 和 Dubinin-Radushkevich 等模型进行了描述。Langmuir 和 Freundlich 模型显示了方便性，Pb(II)在开发的接枝共聚物上的吸附等温线。
