Concentration of heavy metal by pressure-driven membrane methods Original Research Article

The possibility of concentration of the heavy metals using cobalt as an example has been studied. It has been actualized in the membrane reactor at a combination of sorption onto the clay mineral or a cation-exchange resin and the following pressure-driven membrane separation of a mixture. The retention coefficient of Co(II) ions by the OPAM-KN membrane under the quasi-steady mode of long-term operation reaches 0.92 and 0.98 when the montmorillonite clay mineral and KU-2–8n cation-exchange resin is used, respectively. This coefficient is essentially lower when the UPM-20 has been used, viz., it is 0.08 and 0.60 in cases of the former and the latter, respectively. An effect of the sorbents differing in their nature on the purification/concentration process in the so-called hybrid method was determined. Such a conclusion has been reached based on the data on the water state in the dynamic membranes formed by a clay mineral or a cation-exchange resin onto the surface of the supporting OPAM-KN and UPM-20 membranes. The information on the water state has been obtained by the differential-scanning calorimetry method.