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.
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 an impact of the metallurgical wastes dumping site on the following parts of the environment: air, soil and surface waters. Some of the methods used to prevent wastes interactions were showed. The results of the metallurgical wastes leachate samples research, in which toxic metal ions have been found, are presented results of examinations performed on water extracts derived from two types of metallurgical wastes were given. The chemical analysis of water extracts indicate exceeded concentration of toxic metals, such as: lead, arsenic, barium and others. Preliminary results of some metals elimination from the water extracts with PUROLITE ion-exchangers were also presented. The utilised acidous cationit with Na+ groups exchanges the Ba2+ ions in almost 90%, similar to S 930 ionit with chelating groups (Table 5 and 7). Whereas the anionit with hydroxyl groups removes the arsenic ions(V) from the solution with the 60% efficacy (Table 7).
The study of the effectiveness of the removal of anionic natural organic matter (fulvic acids-FA and humic acids-HA) and inorganic anions (F-, Br-, NO3-) in MIEX®DOC process was performed. The influence of physico-chemical parameters of feed water on the process performance was investigated. The ion exchange process was carried out using strongly basic, macroporous polystyrene resin MIEX® by Orica Watercare. The synthetic feed waters differ in composition, i.e. concentration of FA and HA (ca. 6 and 12 mg/L), anions content (F-, Br-, NO3-) and of various alkalinity (ca. 20 and 120 mg/L as CaCO3) were used. The study confirmed the possibility of application of MIEX®DOC process for removal of anionic contaminants from water. It also showed the significant impact of feed water parameters on the process effectiveness. Moreover, the strong dependence of anions (F-, Br-, NO3-) removal, FA and HA concentration on the resin dose was revealed.
In the study, particle size distribution of the MIEX® resin was presented. Such analyses enable to determinate whether presence of fine resin fraction may be the reason for unfavorable membrane blocking during water purification by the hybrid MIEX®DOC – microfiltration/ultrafiltration systems. Granulometric analysis of resin grains using the laser diffraction particle size analyzer (laser granulometer) was carried out as well as the microscopic analysis with scanning electron microscope. The following samples were analyzed: samples of fresh resin (a fresh resin – not used in water treatment processes) and samples of repeatedly used/regenerated resin that were collected to analysis during mixing and after sedimentation process. Particle size distribution was slightly different for fresh resin and for repeatedly used/regenerated resin. The grains sizes of fresh resin reached approximately 60 μm (d10), 120 μm (d50) and 220 μm (d90). Whereas the sizes of repeatedly used/regenerated resin were about 15 μm (d10), 40 μm (d50) and 115-130 μm (d90). The smallest resin grains sizes were in the range of 0.3-0.45 μm. This ensures that the ultrafiltration membranes retain all resin grains, even the smallest ones. Whereas the microfiltration membranes must be appropriately selected to guarantee full separation of the resin grains and at the same time to exclude a membrane pores blocking.