Phosphorus-containing carbon deposits on silica gel Si-100

A series of carbon/silica gel (CS) samples at different concentration of phosphorus compounds (CP) was synthesized by carbonization of glucose in the presence of phosphoric acid on silica gel Si-100 in a rotary reactor in a nitrogen atmosphere at 500 °C (5 h) at a heating rate of 2 and 4 °C/min (from 20 to 500 °C). Prepared CS samples were studied using adsorption (nitrogen, Cd(II)), thermal analysis, titration, and spectroscopic (FTIR, XRF, XRD) methods in gaseous and liquid media. Contributions of nano-, meso-, and macropores to total porosity and specific surface area depend strongly on the CP value and the heating rate. An increase in the CP value enhances the negative surface charge density and the adsorption of Cd(II) characterized by a bi- or trimodal distribution function of Cd(II) binding constant f(Kn) over a broad Kn range.