Co2+ ION SORPTION BY AMORPHOUS AND CRYSTALLINE ZEOLITE SORBENT
Co2+ ion sorption by sorbents of different physical state – aluminosilicate gels and crystalline NaX zeolite – was studied. These NaX zeolites were synthesized by mixing the initial sodium silicate and sodium aluminate aqueous solutions in the proportions so as to ensure the following molar ratios of this mixture: Na2O / SiO2 = 1.2; SiO2 / Al2O3 = 10; H2O / Na2O = 23. Aluminosilicate gel was formed immediately after mixing the above-mentioned solutions. After 72 h of aging at room temperature, the gel was formed in aged aluminosilicate gel – amorphous NaX zeolite. By stirring the slurry for 3 h, crystalline NaX zeolite was obtained at 95 °C. At 23 °C, Co2+ ion sorption kinetics was studied by filling up aluminosilicate gels without aging and after 72 h of aging, and NaX zeolite with of Co2+ concentration 117 mg/l in CoSO4 solution. At this temperature, the aluminosilicate gel sorption capacity was 22.09 mg/g and of crystalline zeolite NaX 22.37 mg/g. In the study conditions, sorption was most intensive during the first 3 minutes.