Cross-linked poly(methyl methacrylate)/multiwall carbon nanotube nanocomposites for environmental treatment

Abstract

Eco-friendly cross-linked poly(methyl methacrylate)/multiwall carbon nanotube nanocomposites with general abbreviation (C-PMMA/CNTs 1-5 ) have been synthesized and applied efficiently for environmental treatment from methyl green (MG) dye. C-PMMA/CNTs 1-5 were prepared via in situ cross-linked polymerization method using 1,12-diaminododecane as the cross-linker. CNTs were enforced with variable loading (2, 5, 10, 20 and 40) wt% in situ while the cross-linking polymerization occurred. The fabricated nanocomposites were spectroscopically regarded by common characterization methods. These include FTIR spectra, XRD diffractograms, SEM & TEM micrographs, and TGA & DTA thermograms. FTIR and XRD showed obvious evidence for the composite formation. A good spreading of CNTs inside C-PMMA matrix has been investigated by SEM and TEM micrographs. TGA showed enhanced thermal stability behavior in all formulations. Our main target in this study is to test the viability of eliminating MG dye from aqueous solutions by C-PMMA/CNT nanocomposites. The C-PMMA/CNT 3 nanocomposite showed Langmuir adsorption capacity of 6.85 mmol/g for MG dye at 25°C. The adsorption equilibrium could be reached within 120 min. The adsorption kinetics of MG onto C-PMMA/CNTs 3 was obeyed very well pseudo-second-order model. Enthalpy (∆H°) and entropy (∆S°) of adsorption were 23.15 kJ/mol and 134.1 J mol −1  K −1 , respectively. The values of ∆H° and ∆G° all designated that the adsorption of MG onto C-PMMA/CNT 3 nanocomposites was a physisorption in nature.