REMOVAL OF Cu(II), Cd(II), Co(II), Zn(II), Cr(VI) FROM WASTEWATER BY STABILIZED NANOSCALE ZERO-VALENT IRON

Abstract

Background. Obtaining sorption materials based on natural raw materials for water purification from pollution by heavy metal ions is an urgent task of our time. Composites with zero-valent iron nanoparticles immobilized on the surface of clay minerals show rather high sorption properties concerning ions of some heavy metals. However, there are only a few proceedings devoted to the physicochemical substantiation of wastewater treatment processes containing a complex mixture of such pollutants. Objective. The purpose of the paper is to study the physicochemical regularities of wastewater treatment from a mixture of ions of heavy metals Cu(II), Cd(II), Co(II), Zn(II), Cr(VI) using stabilized nano dispersed powders of zero-valent iron. Methods. The phase composition and structural-sorption characteristics of palygorskite and composites were studied by X-ray phase analysis and low-temperature adsorption-desorption of nitrogen. The efficiency of removal of metal ions by silicate materials was investigated using the sorption method. The equilibrium concentrations of each of the metals were determined by inductively coupled plasma atomic emission spectrometry. Results. We have investigated the physicochemical features of wastewater treatment containing a complex mixture of heavy metal ions (Cu(II), Cd(II), Zn(II), Co(II), Cr(VI)). The phase composition and structural-sorption properties of stabilized nano dispersed powders of zero-valent iron have been studied. It has been experimentally confirmed that the materials obtained have significantly better sorption properties for the removal of heavy metals from aqueous solutions in comparison with natural palygorskite. Using Freundlich and Langmuir equations sorption isotherms were calculated. Conclusions. It has been established that stabilized nano dispersed powders of zero-valent iron can be successfully used for the purification of wastewater containing a mixture of toxic ions Cu(II), Cd(II), Co(II), Zn(II) and Cr(VI). It is shown that the degree of water purification by the obtained sorbents is 3–5 times higher than that for the unmodified mineral. A significant increase in the values of sorption of anionic forms of Cr(VI), which are difficult to remove from polluted waters by natural ion exchangers, has been determined.