The article is a continuation of a series of scientific works of the authors on the study of the influence of microwave irradiation on the sorption parameters of natural sorbents in the processes of purification of natural and wastewater. Using the atomic absorption method, the sorption ability of the natural sorbent clinoptilolite (zeolite type of structure) to remove Copper, Zinc and Nickel ions from aqueous solutions was studied. It was found that different variants of microwave activation of this mineral (series «Nat», «Stim» and «DIR») lead to a significant increase in the sorption capacity of clinoptilolite by ions of these heavy metals. It is shown that in comparison with similar activation schemes of another natural sorbent of bentonite (clay material), the improvement of sorption parameters of clinoptilolite with respect to heavy metals is not as significant as in the case of bentonite. It is confirmed that in almost all solutions the deposition of heavy metals on clinoptilolite occurs according to the Langmuir or Langmuir-Freundlich model. A similar situation was observed in previous works of the authors on the deposition of heavy metals on bentonite. Using scanning electron microscopy, energy dispersion spectroscopy and X-ray phase analysis, it was found that the deposition of heavy metals on both bentonite and clinoptilolite occurs not only in the form of monolayers of hydrated ions in sorbent micropores (classical model), but also in the form of individual compounds. metals. It has been suggested that the action of microwaves on these sorbents in aqueous solutions improves the structure of their micropores and affects the surface charge, so some parts of the adsorbent become active centers of crystallization of new phases - heavy metal compounds. During adsorption of heavy metal by natural bentonite or clinoptilolite, low-energy adsorption centers predominate, whereas in the case of microwave-irradiated samples of these sorbents, the experimental data correspond to a symmetric quasi-Gaussian distribution of adsorption energy where low- and high-energy regions are present. This fact indicates that electromagnetic treatment stimulates the formation of new adsorption centers.
Potential of Staphylococcus xylosus strain for recovering nickel ions from aqueous solutions