Study on the adsorption of lanthanum(III) from aqueous solution by bamboo charcoal

The adsorption behaviors of La(III) ion on bamboo charcoal were investigated with various chemical methods and IR spectrometry. Parameters studied include the effects of pH, average particle size, initial ion concentration, contact time and temperature by batch method. The results showed that bamboo charcoal could remove La(III) ions effectively from aqueous solution. The loading of La(III) ions was strongly dependent on pH of the medium and the optimal adsorption condition was in HNO3-TEA medium with pH value of 7.20. In the batch system, the modified bamboo charcoal exhibited the highest La(III) ion uptake as 120 mg/g at 298 K, at an initial pH value of 7.20. The adsorption kinetics were tested with Lagergren-first-order model and pseudo-second-order model. The adsorption data were conformed to the Langmuir and Freundlich isotherms, and the correlation coefficients had been evaluated. Thermodynamic parameters such as free energy (ΔG), which were all negative, indicated that the adsorption of La(III) ion onto bamboo charcoal was spontaneous and the positive value of enthalpy (ΔH) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. The characterization of both before and after adsorption of La(III) ion on bamboo charcoal was undertaken using IR spectroscopic technique. The results revealed that bamboo charcoal was a good choice as a biosorbent for the recovery of lanthanum from aqueous solution.