Steady state fluorescence spectroscopic studies on the aggregation of coal derived asphaltene at lower concentration

Steady state fluorescence spectroscopic technique has been used to investigate the aggregation of coal derived asphaltene (CDA) sourced from Lodna Coke Plant situated at Dhanbad, India. The emission spectra of CDA provide information regarding the various stages of onset of aggregation in carbon tetrachloride medium. Almost similar results have also been inferred from the analysis of corresponding excitation spectra. It has been observed that the onset of aggregation of CDA occurs at concentration beyond a concentration of 10 mg L−1. Studies indicate the formation of a trimer at this concentration range. The association constant (K) for the trimer formation has also been evaluated from the spectroscopic data.