Experimental and RSM study of hypercrosslinked polystyrene in elimination of lead, cadmium and nickel ions in single and multi-component systems

Abstract

The aim of this research is to calculate mass transfer and diffusion coefficients of the phases interface, and hypercrosslinked polymer (HCP) pores in the heavy metal adsorption process. The experiments are carried out at a pH of 7, the temperature of 20 ℃, and the initial concentration of 100 mg/L for single and ternary systems and 80 mg/L in the binary systems. The diffusion coefficient, mass flux, and mass transfer coefficient for cadmium ions in the ternary system have measured 0.2963×10−20 m2/s, 0.0818×10−20 mol/m2.s, and 0.2662×10−15 m/s in 10 min, respectively, and the diffusion coefficient, mass flux, and mass transfer coefficient for cadmium ions in the ternary system have measured 0.1954×10−20 m2/s, 0.2153×10−20 mol/m2.s, and 0.4935×10−15 m/s in 50 min, respectively. In the isotherm discussion, kL of 0.03 L/mg, kF of 31.84 mg(1−m). Lm/g, and kS of 0.005(L/mg)m, and the KL of 5.92×10−8 and KL of 0.7588×10−15 m/s in boundary and pores for lead ions, respectively, which shows the direct relation between the isotherm constant and mass transfer coefficient. The mass transfer coefficient in the interface is higher than inside the pores, for instance, for lead ions, KL of 7.60×10−8 m/s and KL of 0.4463×10−15 m/s in boundary and pores, respectively. Besides, KL of 5.60×10−8 m/s and KL of 7.60×10−8 m/s in binary and ternary systems for lead ions, respectively, show a positive influence in increasing the components. Moreover, in the ternary system, KL for lead, nickel, and cadmium ions are 7.60×10−8, 5.51×10−8, and 6.30×10−8 m/s, respectively, which proves the high transfer of lead ions relative to the other ions. Ultimately, response surface methodology was employed and also observed that the quadratic relation between KL and dimensionless numbers was suitable.