Increasing the sorption capacity of the native form of clinoptylolite for Mn2+ ions to obtain sorbents modified with manganese oxides

The object of the research was the process of sorption of Mn2+ ions by natural clinoptilolite (native form) under the influence of ultrasonic (US) radiation for the subsequent production of sorbents modified with manganese oxides, which have additional catalytic and oxidative capacity. Such sorbents with additional functions will be widely used in water purification processes from iron and manganese ions, hydrogen sulphide and a number of organic compounds, as well as highly dispersed and colloidal particles. This will allow combining the processes of purification of dispersed particles and soluble compounds of Fe2+, Mn2+, sulphides. The research was carried out with a clinoptilolite fraction of 1.0–1.5 mm, which is used in water purification processes. It was found that the native form of clinoptilolite has a lower sorption capacity for Mn2+ compared to clinoptilolite previously enriched by washing out impurities. The process of modifying clinoptilolite under the influence of ultrasound made it possible to significantly increase the sorption capacity of the zeolite for Mn2+ ions, compared not only to the native form of clinoptilolite, but also to the previously enriched one. Thus, at ultrasound powers of 8.0; 10.2 and 12.5 W, the sorption capacity of the native form of clinoptilolite increased by 1.66; 2.14 and 2.41 times, compared to the control experiment (without ultrasound). Compared to the enriched clinoptilolite, an increase in sorption capacity is also observed, although somewhat smaller: at powers of 8.0; 10.2 and 12.5 W it increased by 1.14; 1.47 and 1.65 times. It was found that the increase in temperature has little effect on the value of the sorption capacity of clinoptilolite. The value of the temperature coefficient g close to 1.1 indicates the course of the process in the diffusion region. EDX analysis has shown that the sorption of Mn2+ ions occurs mainly by the mechanism of selective ion exchange. The sorption capacity of clinoptilolite modified under adiabatic conditions is lower than under isothermal conditions. However, this method of modification has prospects at a higher mass ratio between the modification solution and zeolite. The results obtained have prospects for use in obtaining sorbents based on natural clinoptilolite with additional catalytic properties.