Multiwalled carbon nanotube-polyurethane (MWCNT/PU) composite adsorbent for safranin T and Pb(II) removal from aqueous solution: Batch and fixed-bed studies

Multiwalled carbon nanotube-polyurethane (MWCNT/PU) composite was synthesized and used as a novel adsorbent for safranin T and Pb(II) removal from aqueous solution. The experimental data conformed to Langmuir isotherm suggesting monolayer adsorption of both dye/metal. The adsorbent proved to be highly efficient with high BET surface area (491 m2/g) and high monolayer adsorption capacity (qm) of 500 mg/g (safranin T) and 270.27 mg/g [Pb(II)]. Column studies gave a breakthrough capacity of 425.25 mg/g (safranin T) and 239.05 mg/g [Pb(II)]. The data followed pseudo-second order kinetics, with both liquid-film and intra-particle diffusion controlling the overall mechanism. The adsorption process was spontaneous and endothermic. The efficiency of the adsorbent for treatment of real wastewater samples under optimized conditions was evaluated.