Application of a cellulose-containing composite material for tungsten extraction from acidic solutions

Currently, high-purity fluorine-containing gases are used in the production of high-purity semiconductor materials in the Russian Federation. The total content of impurities in them should not exceed 10 ppm with a main substance content of 99.999%. In this regard, there is a need to determine impurities in fluorine-containing gases, in particular, in tungsten hexafluoride, with a low detection limit. During the study of the quantitative composition of the gas, there is a need to purify waste water from tungsten, the maximum permissible concentration of which in water objects is 0,05 mg/l. A promising direction is the development of sorbents based on cellulose, the sorption properties of which are generally recognized and studied in many works. It is known that the integration of cellulose into various substrates significantly increases their sorption capacity. One of the main methods of using such composite materials is considered to be immersion in a solution containing a valuable component, the advantages are high sorption capacity in comparison with other natural sorbents, lower cost and environmental friendliness in comparison with materials with higher sorption capacity. In this paper, a method for producing a composite material in the form of a cellulose-containing coating on carbon fiber is proposed, including the stages of washing and drying the anode and cathode, electrochemical deposition of cellulose-containing coatings on the anode with a stepwise increase in voltage, washing the anode deposits and drying to a constant weight. The coating thickness after three deposition cycles was 19,1 - 21,2 pm. Surface studies using scanning electron microscopy showed that the material was macroporous with a maximum pore distribution in the range of 0,5 - 2,0 pm. The tungsten content in solutions was determined using a mass spectrometer with inductively coupled plasma. The sorption capacity of the composite material at pH 2 and a solution temperature of 20 °C was 15,1 - 16,7 mg/g. It was assumed that the sorption of tungsten from acidic solutions occurred primarily by the mechanism of physical sorption and, to a lesser extent, of anion exchange. Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.

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