Influence of bridged monomer on porosity and sorption properties of mesoporous silicas functionalized with diethylenetriamine groups

Mesoporous organosilicas functionalized simultaneously with both pendant amine groups and ethylene/phenylene bridges, were synthesized to evaluate the effect of the bridges incorporated in the silica framework on the structure, porosity and adsorption properties of final materials. It turned out that the presence of the bridges enhanced the formation of porosity but adversely affected the efficiency of amination. DFT theoretical calculation showed that the amine groups can be partially bonded by phenyl groups of the bridges. The obtained materials were tested as sorbents of diclofenac, which is considered as one of the most prominent hazardous pharmaceuticals. High uptakes of diclofenac reaching 842 mg g −1 proved that the obtained materials could be applied for removal of drugs from waters and wastewaters, particularly when high concentrations of pharmaceutical are considered. For the phenylene bridged-based materials the diclofenac adsorption occurs only in the pores while for the others also on the external surface as indicated by different diclofenac desorption kinetics—this observation can be used to modulate the releasing profiles of drugs via proper design of the surface.