The effect of high-temperaturetreatment on the sorption properties of natural blue clay

Relevance. Natural mineral clays are widely used not only in technology, but also in medicine, cosmetology, and the food industry, due to their unique properties. The high degree of dispersion, sorption-adhesive properties of clay materials, as well as the rich mineral composition also determine their therapeutic effect.

Depending on the area and purpose of use, clays are subjected to heat treatment, which can lead to a change in their properties.

The purpose of the work is to study the influence of various heat treatment modes on the sorption properties of clay for its further use in pharmaceutical practice.

Material and methods. The object of study is Kimmeridgian blue powdery of clay blue Undory in the Ulyanovsk region. Determination of clay moisture content was carried out using an AND MF–5 moisture analyzer (Japan). To completely remove moisture from clay by high-temperature treatment, an SNOL 7.2/1100 electric furnace (Lithuania) was used. The influence of the clay calcination regime on the thermal stability of the clay powder and the ongoing endo- and exothermic effects with loss of sample mass was studied using a Q-1500D derivatograph (Hungary). Adsorption activity was assessed by direct spectrophotometry using an SF-56 “LOMO-Spectrum” spectrophotometer (Russia).

Results. DTA of the derivatogram showed the thermal stability of the clay powder in the temperature range from 20°C to 900°C with variations in endo- and exothermic effects. Based on these data, heat treatment modes and sample exposure time were selected. The experiment showed a statistically significant decrease in adsorption activity with increasing temperature and various variations in exposure time.

Conclusions. To preserve the adsorption properties of clay blue Undory when removing moisture from it, it is not rational to use high-temperature treatment. The most optimal parameters for drying clay are: temperature 80 ° C, exposure time - 240 minutes.