Bulgakova A. Controllable synthesis, morphological and sorption properties of zinc, cadmium, and copper(II) sulfides particles

The subject of investigation: processes for producing sorbents based on zinc, cadmium, and copper(II) sulfide from aqueous solutions. The purpose of investigation: to develop the controllable synthesis of zinc, copper(II), and cadmium sulfide from aqueous solutions, to establish the morphological and sorption properties of the particles. Methods of investigation: X-ray diffraction, infrared spectroscopy, scanning electronic microscopy, potentiometric titration, thermal desorption of argon, inductively coupled plasma atomic emission spectroscopy. Theoretical and practical results: varying of pH of the precipitation, the concentration ratio of the reactants, and the initial salt anion upon heat and microwave activation results in precipitation of zinc, cadmium, and copper(II) sulfides with different morphologies. The dependence of the sorption and morphological properties on the synthesis conditions permits improving the sorption capacities of zinc, cadmium, and copper(II) sulfides by changing the precipitation conditions. The characteristics of cadmium ion sorption from aqueous solutions on copper(II) sulfide at different temperatures and рН were investigated. The sorption process obeys the Langmuir equation, which is used to calculate the sorption capacities of copper(II) sulfide. It is shown that the sorption capacity increases with an increase of pH and a decrease of the temperature. The sorption capacity changes from 5.6 mg/g at pH 5 and 35 0C to 15.2 mg/g at pH 7 and 15 0C. The optimization of conditions permits improving the copper(II) sulfide sorption capacity. The pH changes during the sorption obey the Kurbatov equation denoting the sorption process as ion exchange reaction. Scope of use: development of new sorbents for the extraction of heavy metals and radionuclides from aqueous solutions.