Uranium contamination removal from water by an orchid (Vanda tessellata) based biosorbent

The study reports biosorptive removal of uranium(VI) water contamination by a wild epiphytic orchid plant: Vanda tessellata. This orchid plant was chosen based on abundant availability and adsorption efficacy. In batch mode operation the maximum uranium(VI) adsorption capacity was found as 416 mu g g(-1) of dry biomass. The optimum pH for adsorption was neutral (7), and the equilibrium time was 15 min at 30 +/- 5 degrees C temperature. The adsorbent properties were characterized by SEM, EDS, and FTIR techniques. The effects of various variables like pH, initial ion concentration, biosorbent dose, contact time, and temperature on the adsorption process were studied. The Langmuir isotherm showed better agreement (R-2 = 0.987) to describe the adsorption process, and the adsorption process followed pseudo-second-order kinetics. The thermodynamic study showed the endothermic, and spontaneous nature of adsorption in a feasible manner. The adsorbent can be used for developing a remedial method for uranium contamination in the water.

Automated summary

The study demonstrated effective biosorptive removal of uranium(VI) water contamination by a wild epiphytic orchid plant, with a high maximum adsorption capacity of 416 μg g(-1). The optimal pH for adsorption was neutral and the process followed pseudo-second-order kinetics. Thermodynamic study indicated an endothermic and spontaneous nature of the adsorption process.