The adsorption capacities of ion exchangers with N-methyl-D-glucamine (NMDG) groups (Amberlite IRA 743, Lewatit MK 51, Purolite S110 and Purolite S108) relative to V(V) ions were tested in a batch system, taking into account the influence of various parameters, such as the adsorbent mass (0.05-0.20 g), phase contact time (1-240 min), initial concentration (10-150 mg/L), and temperature (293-333 K), as well as in a column system where the variable operating parameters were initial concentration (50, 100 mg/L), bed volume (10, 100 mL) and flow rate (0.6, 6 mL/min). Pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models were used to describe the kinetic studies. The best fit was obtained for the pseudo-second order model. The Langmuir, Freundlich and Temkin adsorption models were used to describe the equilibrium data to acquire better knowledge about the adsorption mechanism. The thermodynamic parameters were also calculated, which showed that the studied processes are endothermic, spontaneous and thermodynamically favorable. The physicochemical properties of the ion exchangers were characterized by nitrogen adsorption/desorption analyses, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photo electron spectroscopy (XPS). The point of zero charge (pHPZC) was also determined.
Keywords: Amberlite IRA 743; Lewatit MK 51; Purolite S108; Purolite S110; adsorption; ion exchangers; vanadium.