Single and Binary System Dye Removal from Colored Textile Wastewater by a Dendrimer as a Polymeric Nanoarchitecture: Equilibrium and Kinetics

This paper deals with the removal of textile dyes from aqueous solutions by a poly(propylene imine) dendrimer (PPI) as a polymeric nanoarchitecture in single and binary (mixture of dyes) systems. Direct Blue 78 (DB78) and Acid Black 26 (AB26) were used as model dyes. The effects of operational parameters such as dendrimer concentration, contact time, dye concentration, inorganic anions (salts), and pH have been studied on dye removal. Adsorption isotherms (Langmuir, Freundlich, and Tempkin models), adsorption kinetics (pseudofirst order, pseudosecond order, and intraparticle diffusion), and dye desorption were studied in single and binary dye systems. It was found that the isotherm data of DB78 and AB26 in single and binary systems of dyes followed the Langmuir isotherm. Adsorption kinetics of dyes in single and binary dye systems were found to conform to a pseudosecond order model. Desorption tests showed that the maximum dye releases of 93 % for DB78 and 86 % for AB26 in a single system and 90 % for DB78 and 84 % for AB26 in a binary system of dyes were achieved in aqueous solution at pH 12. On the basis of the data of the present study, it can be concluded that the dendrimer as a polymeric nanoarchitecture is an eco-friendly adsorbent with a relatively large adsorption capacity and may be a suitable alternative for elimination of dyes from aqueous media.