(594g) Low Temperature Synthesis of Magnetic Carbonaceous Materials Coated with Silica for the Effective Adsorption of Methylene Blue for Aqueous Solution

Low
temperature synthesis of magnetic carbonaceous materials coated with silica for
the effective adsorption of methylene blue for aqueous solution

Reshma
Babu, Hemant Mittal and Saeed M Alhassan^*

Department
of Chemical Engineering, Khalifa University of Science and Technology, PO Box
2533, Abu Dhabi, United Arab Emirates

*E-mail
corresponding author: salhassan@pi.ac.ae

This
work reports the synthesis of silica coated magnetic carbonaceous
adsorbents (MCA-SiO₂) using low temperature hydrothermal
carbonization technique and the feasibility of its capacity to adsorb methylene
blue (MB) dye from aqueous solution. Initially, the carbonaceous precursor (CP)
was prepared from corn starch under saline conditions at 453 K using
hydrothermal method followed by the magnetization of the synthesized CP again using
hydrothermal carbonization at 453 K. Finally, MCA was coated with silica and characterized
using different techniques such as SEM/EDX, TEM, XRD and FTIR. The effect of adsorption
parameters on MB dye removal such as MCA-SiO₂ dose, solution pH and dye
concentration were also investigated. The adsorption behaviour of MCA-SiO₂
was best defined using Langmuir adsorption isotherm
model and pseudo-second-order kinetics rate equation. The mechanism of the dye
diffusion was governed by the combination of intraparticle diffusion as well as
the film diffusion mechanisms. The versatility of MCA-SiO₂ was also
checked for the adsorption of a number of cationic and anionic dyes and it
showed much better performance for the cationic dyes as compared to anionic
dyes. Furthermore, the reusability and regeneration properties of MCA-SiO₂
were examined and found to be successful for consecutive five cycles of adsorption–desorption.