At present, industrial development is increasing pollution of soils, air and natural waters. These pollutants have a negative effect on the health and life of living organisms. Metals which interfere with the natural biological balance and inhibit self-cleaning processes in water bodies have particularly toxic effects. Cobalt, which gets into the environment from industrial sewage from electrochemical plants and the metallurgical industry, also belong to this group. This is also relatively rare and precious element, so it is important to look for additional sources of its recovery. Chemical and physicochemical methods such as: precipitation, extraction, membrane processes – nanofiltration, reverse osmosis, sorption and ion exchange are used to recover cobalt. The choice of method depends on: the kind and composition of wastewaters as well as on form and concentration of the pollutants. Ion exchange resins produced by Purolite which were used to remove cobalt ions from solutions with concentrations corresponding to its contents in galvanic wastewater was the subject of the study. It has been shown that the C 160 ion exchange resin has the best the sorption properties for Co2+ ions (54.7 mg/g). In case of this ion exchange resin, after sorption process carried out in one 50 minute cycle, cobalt concentration decreased from about 30 g/L to about 9 g/L. The values of the sorption capacity do not depend on the method of introducing the solution into an ion exchange column (pouring or dropping). E ach of the tested ion exchange resins is characterized by a high degree of cobalt concentration after regeneration using mineral acids, which can be advantageous in selecting the recovery method for this metal.
The paper presents results of research on cobalt and nickel ions removal from monocomponent solutions using Purolite ion exchange resins. It has been shown that C 160 ion exchange resin has the best sorption properties for both ions (Qe – 72.5 mg Co/g and 88.2 mg Ni/g). Regeneration process of this ion exchanger has high efficiency, achieving about 93% for cobalt ions and about 84% in case of nickel ions. It has been shown that the use of ion exchange method with suitable ion exchange resins guarantees effective removal of cobalt and nickel ions from solutions with very high concentrations corresponding to contents of these metals in industrial wastewaters (e.g. galvanic). In case of C 160 ion exchange resin, after the sorption process is carried out in one 50 minute cycle, the cobalt concentration decreased from about 30 000 mg/L to about 9 500 mg/L (approx. 68%), whereas nickel concentration reached about 6 300 mg/L (approx. 79%). Studied chelating resins don’t have such high sorption capacities. In their case, it is required to convert cobalt and nickel ions into complex forms. The kinetics of studied processes were described by pseudo-second order equations.