Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6584169 | Chemical Engineering Journal | 2015 | 11 Pages |
Abstract
A renewable, amphoteric functionalized mesoporous silica (AG-SBA-15) was synthesized with a two-steps process: firstly, aluminum atoms was incorporated into the framework of SBA-15 and then melamine-based dendrimers groups were anchored onto the Al-substituted SBA-15. The amphoteric AG-SBA-15 kept an ordered hexagonal mesostructure after the functionalization and regeneration processes and exhibited an excellent performance for simultaneous removal of Cu(II) cations and Cr2O72â metalloid anions from aqueous solution, with the maximum adsorption capacity of 2.216Â mmol/g Cu(II) and 3.305Â mmol/g Cr2O72â, respectively. Batch adsorption experiments results indicated that the optimized pH value for simultaneous removal of Cu(II) and Cr2O72â was 5.0. The adsorption rate was extremely fast and the equilibrium reached within 30Â min. The adsorption of Cu(II) and Cr2O72â by AG-SBA-15 were fitted better to Langmuir than Freundlich Model and thermodynamic parameters revealed the spontaneous and exothermic nature of the adsorption. Reusability studies of AG-SBA-15 were carried out by 5 repeated adsorption-desorption cycles and the results confirmed that AG-SBA-15 could be easily reused with little loss in removal efficiency. Furthermore, simultaneous removal mechanism of Cu(II) and Cr2O72â by AG-SBA-15 was proposed by X-ray photoelectron spectroscope analysis (XPS), which revealed that Cu(II) was adsorbed by a combination of electrostatic interaction, while Cr(VI) could be immobilized by reduction.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Qiuping Wu, Ruirong You, Qiufeng Lv, Yali Xu, Weijie You, Yan Yu,