Sorption of Reactive blue 19 onto freshwater algae and seaweed

The potential of freshwater algae (Spirulina platensis) and seaweed (Gracilaria edulis) for removing reactive blue 19 (RB 19) were investigated using batch adsorption techniques. The effects of various experimental parameters (Solution pH, initial dye concentration, contact time, adsorbent dosage, agitation speed, particle size and temperature) have been evaluated and optimal experimental conditions were ascertained. The biomass exhibited maximum dye uptake at acidic pH (pH = 1.5) due to electrostatic interactions between the biomass and the dye particles. Several isotherm models like, Langmuir, Freundlich, Dubinin-Radushkevich and Temkin adsorption isotherms were employed to monitor the adsorption behaviour. The pseudo-first-order model, pseudo-second-order kinetic model, Elovich model and intra-particle diffusion models were applied to the adsorption dynamic data. Pseudo-second-order fitted well in line with experimental data. Temkin adsorption isotherm best suited the adsorption data over the entire range of concentrations compared to other models.