ANALISIS OF ADSORPTION ISOTHERMS OF ZINC IONS ON BENTONITE AFTER PROCESSING IT WITH ULTRAHIGH-FREQUENCY RADIATION

Abstract

This article provides research of adsorption characteristics of natural argillaceous material bentonite, processed by means of previously moisturizing and radiation with ultrahigh-frequency electromagnetic waves (i.e. “microwaves”). The research was aimed at studying the possibility to enhance efficiency of sorption purification of water from zinc ions by low cost sorbents. Methodology. Adsorption isotherms of zinc ions before and after irradiation by microwaves were obtained in static conditions on model solutions of zinc sulphate. We calculated adsorption parameters of bentonite, processed with the use of microwaves and native samples, by applying the Freundlich equation. Results. The boundary capacity of irradiated sorbent by zinc is approximately 0,027 mmol/g (or 1,78 mg/g), and for the native bentonite the value of the same parameter is 0,019 mmol/g (1,23 mg/g). The joint action of two factors – microwave irradiation and hydrothermal destruction of the surface of crystals – affects the surface structure of the clay material, the distribution of the macro and micropores, the activation of the adsorbing surface, which, in turn, leads to a change in the sorption parameters. After calculating the energy efficiency of the typical process of regeneration of sorbents – with calcination (E1), reduced to the unit mass of the sorbent (1 kg), the estimated energy consumption was obtained: E1 = 6.25 kW/kg. The method proposed by the authors uses the microwaves E2 = 0.45 kW/kg, which is an order of magnitude smaller than the energy consumption in the method of calcination. Originality. For the first time, we have studied the impact of microwaves on efficiency of removal of zinc ions from water by sorption onto bentonite. Practical value. It is suggested to use such a method of preparation of sorbent before the main flow of contaminated water in the process of wastewater treatment of small establishments. References 14, tables 1, figures 3.