Investigation of performance of bimodal/functionalized mesoprorous silica nanoparticles on the adsorption of methylene blue from aqueous solution

Document Type: Original Research Paper

Authors

1 Faculty of chemistry, Amirkabir University of Technology, Tehran, Iran

2 Downstream Devision, Research institute of petroleum industry, Tehran, Iran

3 Research institute of petroleum industry, Tehran, Iran

Abstract

In this study, bimodal mesoporous silica, i.e. UVM-7, was synthesized and functionalized with
sulfonic acid and characterized using XRD, nitrogen physisorption, SEM, TEM and acid/base
titration. The results displayed that bimodal mesopore structure was firmly formed and acidic
functional groups were grafted on the surface of the UVM-7. The concentration of the acidic
functional groups was determined via titration by the standard NaOH solution. At the second
step, the adsorption of methylene blue from aqueous solutions onto UVM-7 and UVM-7/
SO3H was investigated. The effect of PH, temperature, dye concentration, salt concentration
and contact time on the adsorption of methylene blue was studied. The adsorption equilibrium
isotherms were well fitted to Langmuir rather than Freundlich model. Methylene blue
adsorption on UVM-7 increases with increasing the temperature and PH, which indicates
that the process is endothermic. Maximum adsorption capacity of methylene blue by UVM-7
and UVM-7/SO3H were 107.5 mg/g and 129.9 mg/g, respectively. The adsorption kinetics of
methylene blue for both UVM-7 and UVM-SO3H were pseudo-second order and well fitted to
Langmuir model.

Keywords