Adsorption properties of Silochrom chemically modified with nickel acetylacetonate

One of the areas of development of gas chromatography is the creation of new chromatographic materials that have improved sorption and analytical characteristics. In this work, for the first time, a new sorbent based on Silochrom C-120 modified with nickel acetylacetonate was studied using a complex of physico-chemical methods. It has been established that due to chemical modification of silica gel surface with nickel acetylacetonate the surface area of the specific surface decreases from 112 to 98 m2/g and surface acidity diminishes by 1.2 pH units. Using the thermogravimetric analysis it has been revealed that the obtained sorbent can be used in gas chromatography up to 290°C. Gas chromatography method was used to investigate the adsorption properties of the modified materials. According to the retention data of adsorbates: n-alkanes (C6-C9), benzene, ethanol, nitropropane and butanone-2 the differential molar adsorption energy q̄dif, 1, Henry adsorption constants К1,С, the differential molar entropy ΔS̄S1 and Δ q̄dif, 1 (special) of adsorbates in dispersion and specific interactions were calculated. The influence of the modifying additive on the changings in the thermodynamic retention characteristics of all sorbates because of the manifestation of specific sorbate-sorbent interactions has been shown. The highest values of the thermodynamic parameters were indicative for sorbates forming hydrogen bonds and capable of donor-acceptor interaction