nitric acid

It was studied the Processes of ensuring chemical stability (stabilization) of starch nitrate obtained by nitration of starch by two ways: nitric acid and nitric-sulfuric acid mixture. It has been confirmed that, in the first case, starch nitrate has much higher stability due to the absence of low-stable sulfuric acid esters. It is shown that to ensure it in this case, 10 minutes of washing of starch nitrate in  0,19 m3/kg of hot water (95°С) is sufficient.

The article deals with the results of the experiments and studies of nitric acid units in industry and establishes the patterns in NO oxidation under dynamic conditions in a gas phase and on the surface of phase separation considering also packing options.

The content of zinc, cadmium, lead, and copper in honey varieties was determined by the method of stripping voltammetry. Samples preparing was made by three different methods: dry and hydro ashing, as well by “hydro” mineralization and dry ashing. It was found that all methods of samples preparing can be used for destroying honey matrix, but the combined method of samples preparing is the most efficient one for ions of heavy metals extracting and provides accuracy of the definition.

The article is devoted to the preparation of adsorbents for polymer adsorption on their surface. Adsorption of polymers on the surface of adsorbents from a solution has been widely developed and received a great deal of attention in research works, which prove the topicality of its use in development of new composite materials and solve many problems concerning the polymers characteristics and properties. The adsorbents drawbacks, i.e. small specific surface area, diameter of the primary pores and their amounthave been determined.