Jiří Štamberg

The influence of porosity of discrete particles upon their apparent dimensions as measured by the Coulter principle

Abstract Highly porous particles furnish, due to their porosity, smaller Coulter diameters and Coulter volumes than the real particle size and envelope volume, respectively. Finding a relation between these variables (eqn. 4) makes the determination of the latter easier. In addition to the readily obtainable Coulter and porosity data, only one empirical constant for each material class has to be determined.

Surface oriented mercuration of poly(vinylaromatics)

Abstract The mercuration of styrene-divinylbenzene co-polymers can be directed either into the bulk or to the surface of the particles by choosing the reaction medium. Taking macroreticular co-polymers, e.g. Amberlite XAD 2 or XAD 4, the substitution can be limited to a narrow layer of the inner surface of the material, resulting in a rapid ion exchange with extremely high selectivity towards chloride ions.

Spherical composite sorbent consisting of cellulose and mercurated novolac

Abstract A composite sorbent consisting of bead cellulose and mercurated novolac was prepared by a two-stage process involving suspension preparation of the composite bead cellulose/novolac followed by mercuration. The highest mercury content in the sorbent thus obtained was 11.3%. The formation of the sorbent was investigated in greater detail with respect to novolac content and mercuration conditions. Its sorption properties were measured by using sorption of NaCl and thiourea from aqueous solutions.

A composite sorbent based on bead cellulose and mercurated novolac

Abstract A composite material, bead cellulose-novolac, was prepared and transformed by mercuration with mercury(II) acetate into a sorbent containing Hg+ ion-exchange groups. The group of mercuration was followed by measuring the time and concentration dependence. Materials with various mercury content were obtained, with the highest attained mercury content 35.4%. Even at the highest novolac content and degree of mercuration the sorbents showed high swelling in water. The sorption properties were investigated using the sorption of chloride anions from aqueous solutions by measuring the time dependence of sorption and the sorption isotherm. The sorbent possesses a high rate of sorption in addition to the well-known high selectivity of mercurated polymer structures.