Phosphorus-Containing Polybutadiene Rubber-Bentonite Hybrid Composite for the Removal of Rhodamine 6G from Water

摘要

Here is reported the adsorption of rhodamine 6G from aqueous solution using a phosphorus-containing polybutadiene rubber-bentonite hybrid composite. The polybutadiene rubber-bentonite hybrid composite was synthesized via oxidative chlorophosphorylation of polybutadiene rubber and bentonite with subsequent hydrolysis. The static exchange capacity of the polybutadiene rubber-bentonite hybrid composite and the concentration of phosphorus were evaluated. The functional groups present in the polybutadiene rubber-bentonite hybrid composite were characterized by infrared spectroscopy. The adsorption of rhodamine 6G on the polybutadiene rubber-bentonite hybrid composite was investigated on the basis of initial rhodamine 6G concentration, contact time, and temperature. The equilibrium isotherm was analyzed using Langmuir, Freundlich, and Dubinin-Radushkevich models. The adsorption equilibrium measurements of rhodamine 6G in solution correlated well with the Langmuir isotherm equation. This model revealed that the maximum monolayer adsorption capacity of polybutadiene rubber-bentonite hybrid composite was 32.2 mg g(-1). Pseudo first-order, pseudo second-order, and intraparticle diffusion models were used to characterize the adsorption kinetics of rhodamine 6G. The dynamic data fitted well with the pseudo second-order kinetic model. The Gibbs free energy, enthalpy, and entropy changes indicated that the rhodamine 6G adsorption on polybutadiene rubber-bentonite hybrid composite was spontaneous and endothermic. The results were compared with corresponding data in the literature. This study demonstrates that the polybutadiene rubber-bentonite hybrid composite is an effective adsorbent for rhodamine 6G.