Sorption ability of the chitosan-modified natural zeolite for Pb 2+ , Cd 2+ , and Cu 2+ cations was investigated. The influence of time and concentration of heavy metals on their sorption from concentrated (85% H 3 PO 4 ) phosphoric acid was determined. At 20 and 40 min of sorption curves, there are a number of maxima probably due to desorption of cations from the sorbent into the acid. According to the results, sorption of the modified zeolite for lead cation is the least in the whole interval of time. In the case of equal concentrations of all cations (C Pb = C Cd = C Cu ), sorption of lead, cadmium, and copper was 94.81-95.09%, 96.55-97.50%, and 97.53-98.14%, respectively. Sorption curves in the case of equal Pb 2+ and Cd 2+ , but higher concentrations of Cu 2+ , are the same for all cations. Sorption of cadmium varies from 95.48% to 97.55%. Copper and lead sorbed in a less amount, in the case of (С Рb = С Cd < С Cu ), their sorption in 10 min was 95.42% and 97.55%, respectively. As in the case of equal concentrations of all cations (C Pb = C Cd = C Cu ), the sorptions of copper, cadmium, and lead were (92.09-96.93%), (92.13-95.37%), and (91.35-94.45%), respectively, in the case of (С Рb = С Cu < С Cd ).Physico-chemical methods of analysis are as follows: Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray powder diffraction patterns, and Brunauer-Emmett-Teller have shown that natural zeolite is activated without destroying the structure and adsorbs lead, as well as cadmium and copper cations.

The paper examines influence of the modifying additives on properties of Karatau and Chilisay dispersed phosphorites. Authors have revealed effects of temperature and the nature of activating additives on the content of assimilated in Trilon B P2O5; on chloral-and lemon-soluble phosphate forms in derived products as well. It is shown, that Chilisay phosphorite is exposed to the greatest structural changes in dispersion process in all temperature intervals supposing the presence of modifying additives.

This paper presents the systematic studies of the sorption capacity of natural zeolite with respect to In3+ and Ga3+ cations in the model systems “natural zeolite–In3+–H2O” and “natural zeolite–In3+–Ga3+–H2O”, while varying a number of the main process factors. The patterns of sorption of In3+ and Ga3+ cations by the natural zeolite of the Shankanai deposit are revealed, depending on the zeolite vs. solution ratio, temperature, and time. It is shown that the sorption of In3+ cations by natural zeolite can be controlled by the process duration. The longer the process, the less the sorption by natural zeolite. It has been found that the sorption of In3+ cations in the “natural zeolite–In3+–Ga3+–H2O” model system depends on the amount of zeolite and temperature, and the sorption of Ga3+ cations depends on the temperature and time. The physicochemical characteristics of the spent sorbents confirm the sorption of the cations, present in the systems under study.