Adsorption of Reactive Black 5 onto quaternized 2-dimethylaminoethyl methacrylate based polymer/clay nanocomposites

Abstract

[2-(Methacryloyloxy)ethyl]dimethylhexadecylammonium bromide (DMAC16) was synthesized by means of quaternization of 2-dimethylaminoethyl methacrylate with 1-bromohexadecane. Poly(DMAC16) and poly(DMAC16)-bentonite nanocomposites having different amount (3, 5, 7, 10, 15 wt%) of bentonite were prepared by in situ suspension polymerization in the presence of ethyleneglycol dimethacrylate and 2,2′-azo-bis-isobutyronitrile as a crosslinking agent and initiator, respectively. Polymer/clay nanocomposites were characterized by using Fourier transform infrared spectrophotometer, thermogravimetric analyser, X-ray diffraction analyser, energy dispersive X-ray attached scanning electron microscope and zetameter. Adsorption behaviors of bentonite, poly(DMAC16) and nanocomposites towards Reactive Black 5 (RB5) were investigated with respect to solution pH. Adsorption capacities of nanocomposites were found to be higher than those of bentonite and poly(DMAC16) in most cases. Additionally, the highest adsorption capacity was obtained with the nanocomposite containing 10 % of bentonite (PNc10) at all studied pH values. Effects of various parameters such as contact time, initial dye concentration, and temperature on the adsorption capability of PNc10 were also evaluated. According to kinetic and isothermal studies, adsorption processes of RB5 onto PNc10 were fitted to Langmuir isotherm and pseudo-second-order kinetic model well. Maximum adsorption capacity of PNc10 from the Langmuir isotherm model at 40 °C were found to be 833.3 mg g−1. Thermodynamic parameters such as $$\Delta G^{\circ}$$ , $$\Delta H^{\circ}$$ , $$\Delta S^{\circ}$$ and E a were also determined for all over the process.