The molecular aggregation of pyronin Y in natural bentonite clay suspension

Molecular aggregates of Merocyanine 540 in aqueous suspensions containing natural and CTAB-modified bentonite

“…These chemicals were used without further purification. The cation exchange capacity (CEC) of the natural bentonite obtained from Ordu/Ünye in Turkey was determined to be 74 meq/100 g clay by the methylene blue adsorption technique [2].…”

“…3b To determine the effect of the amount of the clay minerals on the spectral features of MC-540, the absorption and fluorescence spectra of the dye in the clay suspensions were studied in the range of 0.1 to 10.0% CEC. In the dye-clay interaction, it is known that certain factors govern the spectral characteristics of dye [2]. In Fig.…”

“…When the dye molecules are adsorbed on clay particles in aqueous suspension, their absorption and fluorescence spectra are very different compared to those in water [2]. Such spectroscopic studies can put forward information about the molecular behavior of dye molecules on clay surfaces, the interaction between π electrons of dye and oxygen plane of clay surfaces, and the molecular aggregation structures of dye molecules in clay dispersion [2,3]. The molecular aggregation or excitons considerably changes the photophysical properties of dye compounds compared to their monomeric forms [4].…”

“…In general, H-aggregate structures are nonfluorescent and characterized with a red-shifted absorption band compared to that of monomeric species. In contrast, J-aggregates show a red-shifting and narrow absorption band compared to that of the monomer, and they are strong fluorescent species [2,4,8]. Chemically modified clays and clay minerals are an effective and popular class of adsorptive materials [9].…”

Preparation and characterization of “green” hybrid clay-dye nanopigments

“…1. The cation exchange capacity (CEC) of the bentonite from Ordu/Unye, Turkey, was determined as 74 meq/100 g clay by the methylene blue adsorption technique [16,17].…”