Adsorptive removal of toxic dyes from aqueous phase using notorious weed Lantana camara (Linn.) as biosorbent

The potential of Lantana camara L. in raw (LR) and modified form (LM) for adsorptive removal of two basic dyes, namely Rhodamine B (RB) and methylene blue (MB), from aqueous solution has been investigated. The adsorbent was characterized by various analytical techniques. The results obtained indicate that adsorption of the dyes strongly depends on pH, initial dye concentration, contact time, and presence of surfactant in batch mode and on flow rate and bed depth in column mode. Kinetic studies revealed that removal of the dyes was governed by pseudo-second-order kinetics and a film diffusion mechanism controls the overall rate of the sorption process. The equilibrium adsorption data were interpreted using various isotherm models, and the data were best fit by the Freundlich isotherm model. Modified adsorbent displayed improved adsorption capacity for RB and MB of 34.24–147.05 mg/g and 23.25–111.12 mg/g, respectively, at 30 °C. Thermodynamic parameters indicated that the dye removal process was spontaneous, endothermic, and chemical in nature. The highest desorption efficiency of spent adsorbent was achieved using sulfuric acid (1 M). The results show that LM has considerable potential for removal of RB and MB from aqueous solution.