Chemometric Characterization of Synthetic Dye Sorption onto Slovakian River Sediments: A Laboratory Batch Experiment

The aim of the work was to characterize the sorption of cationic dyes thioflavine T (ThT) and methylene blue (MB) onto selected Slovakian river sediments using chemometric approaches including principal component analysis (PCA) and cluster analysis (CA). Also, the potential of mentioned multivariate analyses for comparison of studied objects (river sediments or river and model waters) as well as in finding relationships between the variables describing the physico-chemical characteristics of studied matrices or waters and sorption/desorption characteristics of matrices for dyes binding under laboratory conditions was evaluated. Parameters describing the physico-chemical characteristics of sediments include: pH, pHzpc, or cation-exchange capacity; and in the case of waters: pH, conductivity, water hardness, content of dissolved solids or presence of organic compounds. From the comparison of dye sorption onto sediments, it was found that sorption of thiazine dye MB was minimally 1.5-times higher than sorption of benzothiazole dye ThT. Sorption capacities Qs reached the maximum values in the case of sediments originated from Dudvah River (MB-Qs = 8.70 ± 0.42 mg g−1; ThT-Qs = 5.03 ± 0.28 mg g−1; ±SD). Obtained results showed that applied methods of multivariate analyses represent a suitable tool for evaluation of sorption/desorption processes of organic xenobiotics binding in sediments.