Chlorates(VII) removal on Dowex™PSR-2 resin

Lately there has been observed the increased presence of chlorates(VII) in the natural environment which can affect human health negatively. Therefore the removal of chlorate(VII) ions using the gel type resin functionalized with the tri-n-butyl ammonium (Dowex™PSR-2) from waters was studied. The main aim was to evaluate the effects of experimental conditions including contact time, initial solution concentration, pH and temperature on chlorate(VII) ions removal as well as the anion exchanger properties on chlorate(VII) ions sorption. It was found that only the pseudo second order model described the experimental data well and the intraparticle diffusion was not the rate-limiting step. According to the Freundlich model, the qe value was to be 69.26 mg/g at optimum conditions (pH 7.0 at 25 oC)

Modified fly ash and zeolites as an effective adsorbent for metal ions from aqueous solution

Zeolite Na–X and chitosan-modified Na–X–CS were used as adsorbents for the removal of Cu(II), Fe(III), Mn(II) and Zn(II) from aqueous solutions. They were prepared based on fly ash by hydrothermal reaction using the NaOH solution under controlled conditions. Characterization of the Na–X and Na–X–CS sorbents was made using Fourier transform infrared spectroscopy with the attenuated total reflection mode, X-ray fluorescence and X-ray diffraction, nitrogen adsorption and desorption, acidity measurements and scanning electron microscopy techniques. The effects of adsorption time, the amount of sorbent and the concentration of metal ions on the removal percentage and sorption capacities were studied. The sorption percentage increased with the increasing phase contact time and zeolite amount. The adsorption mechanism was also discussed. The results revealed that Na–X–CS adsorbs Cu(II), Fe(III), Mn(II) and Zn(II) ions more effectively than zeolite Na–X and proved that modification by CS leads to an increase in the adsorption efficiency of the zeolites