Abstract
In this work, new copolymers P1-P9 were synthesized by oxidative copolymerization of aniline and 2-[2-chloro-1-methylbut-2-en-1-yl]aniline in HCl solution. The resulting copolymers were characterized with nitrogen adsorption-desorption isotherms, particle size. The equilibrium, kinetics, isotherms and thermodynamics of adsorption of methyl orange azo dye from aqueous solutions on P1-P9 copolymers have been studied. The influence of physicochemical variables (dosage, contact time, pH, dye concentration, temperature, ionic strength of the solution) on the specific adsorption of dye was determined. It is shown that P1-P4 copolymers are able to remove dye from aqueous solutions in a wide range of concentrations with efficiency up to 99.27%. The adsorption of methyl orange follows the Langmuir model (correlation coefficient is 0.9852-0.9990), which corresponds to monolayer adsorption on a homogeneous surface. The kinetics of dye adsorption is described by a pseudo-second-order equation, which is characteristic of chemisorption. Thermodynamic parameters of adsorption have been determined, allowing us to conclude that dye adsorption is a spontaneous endothermic process. It is shown that P1-P4 exhibit good adsorption capacity up to 110 mg/g. These copolymers retain high efficiency in five repeated adsorption-desorption cycles. The developed materials are considered to be suitable as cheap regenerated sorbents for anionic pollutants in wastewater.