Removal of Synthetic Dyes by Dried Biomass of Freshwater Moss Vesicularia Dubyana: A Batch Biosorption Study

In this work the biosorption of cationic dyes thioflavin T (TT) and methylene blue (MB) from single and binary solutions on dried biomass of freshwater moss Vesicularia dubyana as a function of contact time, pH, and biomass or sorbate concentration has been investigated. The prediction of maximum sorption capacities using adsorption isotherm models were also realized. Biosorption of TT and MB is a rapid process strongly affected by solution pH. Maximum sorption capacities Q(max) calculated from Langmuir isotherm were 119 +/- 11 mg/g for TT and 229 +/- 9 mg/g for MB. In binary mixture, the presence of MB caused significant decrease of TT sorption, advocating the competitive sorption between TT and MB. Results revealed that V. dubyana biomass exhibited significantly higher affinity to thiazine dye MB in comparison with benzothiazole dye TT from both single and binary solutions. Based on the obtained results, the competitive effects in binary system can substantially influence the sorption process and should be thoroughly evaluated before application of selected adsorbents for removal of basic dyes from colored effluents.