Synthesis and characterization of silica gels functionalized with monochlorotriazinyl β-cyclodextrin and their sorption capacities towards organic compounds

Different supports, containing a new derivative of beta-cyclodextrin - monochlorotriazinyl beta-cyclodextrin (beta-CDMCT) - used for the reduction of pollutants in waste water, have been prepared. They are based on silica gel, initially either coated with polyethyleneimine (PEI) or grafted with 3-aminopropyltrimethoxysilane, functionalized in a second step with beta-CDMCT. In order to obtain sorbents with high beta-cyclodextrin content and maximum accessibility of the beta-CD cavity, the funtionalization was studied while varying experimental conditions. Thermogravimetry, Raman spectroscopy, specific surface area and pore size distribution were used for the characterization of supports. Sorption experiments show that these sorbents have sorption capacities towards some organic pollutants. The mechanism of sorption is both physical adsorption in the polymer network (for supports obtained by coating) and/or the formation of an inclusion complex between beta-CDMCT and guest molecules.