Synthesis Of Fe@C Core-shell Particle And Pore-Expanded MCM-41and Their Applications In Water Treatment

More and more seious contamination of water makes us to find an effective andpractical method to deal with the waste water. Zero valent iron (ZVI) attracts moreand more concerns since it is cheap, reactive, and easy to get. Not only can ZVIreduce the organic pollutants directly, but also it can oxidize them with the help ofdissolved oxygen. In addition, mesoporous silica has drawn comprehensive concernsince it was synthesized. Its bigger surface area and pore volume make it a kind ofpromising material in the adsorption of pollutants. In this paper, we successfullysynthesized Fe@C core-shell particle and pore-expanded MCM-41. Furthermore,their applications in the water treatment have been investigated as following:1. Fe@C core-shell particles were successfully synthesized by coating Fe2O3particles with resorcinol-formaldehyde resins (RFs) and then calcining to make theRFs carbonize, and at the same time to reduce the core to Fe. Furthermore, a layer ofSiO2was inserted between the core and the RF shell. After the RF has carbonized, theSiO2would be removed by etching. In this way, Fe@C yolk-shell particles weresuccessfully synthesized. Compared with Fe@C core-shell particle, Fe@C yolk-shellparticle has bigger surface area.2. Both Fe@C core-shell and Fe@C yolk-shell particle have showed theexcellent performance on degradation of4-CP. They can degrade4-CP rapidly andthoroughly. The degradation process fit well with a two-stage first-order kinetic. Thefirst stage is an initial slow degradation period and the following second stage is arapid degradation period. Specially, Fe@C yolk-shell particles can degrade the4-CP to a concentration below the HPLC detection limit within12minutes.3. Thanks to the protection by the carbon shell, Fe@C yolk-shell particle isstable and can be stored for at least half an year. The magnetic property of the particleenable easy separation. The particles also show favorable reusability without anydecrease in removal efficiency. Even if the activity decreases to a certain extent afterprolonged exposure to air and water, the particles can be regenerated to their originalperformance again.4. Pore-expanded MCM-41was successfully synthesized by adding amine asexpander. After the expandation, the diameter of the pore enlarges from3nm to5nm,and the pore volume increases from0.9067cm3g-1to1.6401cm3g-1. Thepore-expanded MCM-41particle shows a better performance on the adsorption of dye.Compared with MCM-41particle, it can adsorb more Rhodamine B.