| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1520447 | Materials Chemistry and Physics | 2016 | 10 Pages |
•Functionalization of Kaolin with amine groups through Michael addition reaction.•Removal of copper ions via aminated Kaolin.•Surface modification of Kaolin via bioinspired chemistry.•Amine functionalized Kaolin for environmental application.
Adsorption has been well regarded as a promising and efficient method for the removal of low concentration heavy metal ions in aqueous solutions. And kaolin has been considered as a kind of low cost and environment-friendly adsorbent for its abundant in nature. But the low adsorption capacity to heavy metal ions and severe aggregation in solution restrains its application. In this work, an environment-friendly adsorbent (denoted as Kaolin-PDA-PEI) was prepared based on mussel inspired chemistry and Michael addition reaction between high reaction activity of polydopamine (PDA) and polyethyleneimine (PEI), which was possesses a number of amine groups. The amine groups have displayed strong adsorption affinity towards copper ions. The successful modification of Kaolin by PDA and PEI was confirmed by a series of analyses, such as Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetry analysis and X-ray photoelectron spectroscopy. The effects of various parameters such as contact time, pH, initial concentrations of copper ions and temperature on copper ion adsorption by Kaolin-PDA-PEI were investigated. Kaolin-PDA-PEI shows higher adsorption capacity as compared with the raw Kaolin. The kinetic adsorption data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The Langmuir isotherm and Freundlich isotherm equilibrium model were applied to adsorption isotherm data to find the better fit isotherm. The results showed that adsorption process was well fitted by Langmuir isotherm model. The values of thermodynamics constants such as entropy change (ΔS0), enthalpy change (ΔH0) and Gibbs free energy (ΔG0) were also calculated. The results indicated that the adsorption process of Kaolin-PDA-PEI were endothermic and spontaneous.
Graphical abstractAmino groups functionalized Kaolin was facilely prepared via mussel inspired chemistry. The modified Kaolin exhibited much enhanced adsorption capability toward heavy metal ions.Figure optionsDownload full-size imageDownload as PowerPoint slide
