کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
145254 | 456336 | 2016 | 9 صفحه PDF | دانلود رایگان |
• Fe3O4@SiO2 nanospheres are synthesized successfully.
• Fe3O4@SiO2 nanospheres have high removal ability of CR from solutions.
• Fe3O4@SiO2 nanospheres can be easily separated from solution using magnetic separation method.
• Fe3O4@SiO2 nanospheres have high reusability and stability.
Fe3O4 nanoparticles were synthesized by hydrothermal technique and then modified with tetraethyl orthosilicate to form Fe3O4@SiO2 nanospheres through Stöber method. The characterization results of X-ray diffraction, Fourier transformed infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and magnetic measurements evidenced the successful synthesis of Fe3O4@SiO2 nanospheres. The as-prepared Fe3O4@SiO2 was applied as adsorbent to remove congo red (CR) from aqueous solutions at different experimental conditions, and the results indicated that CR adsorption on Fe3O4@SiO2 was strongly pH-dependent and weakly ionic strength-dependent at relative low pH values, indicating that the adsorption was mainly dominated by electrostatic interactions. The maximum adsorption capacities of CR on Fe3O4@SiO2 were calculated to be 54.64 mg/g from Sips model and 50.54 mg/g from Langmuir model at T = 308 K and pH = 5.3. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption of CR on Fe3O4@SiO2 was an spontaneous and endothermic process. The CR-adsorbed Fe3O4@SiO2 nanospheres could be easily separated from aqueous solutions using magnetic separation technique within 40 s. These results suggested that the Fe3O4@SiO2 nanospheres might be suitable materials for the efficient separation of dye pollutants from aqueous solutions in possible real applications.
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Journal: Chemical Engineering Journal - Volume 306, 15 December 2016, Pages 280–288