Comparison of silver and palladium nanoparticles loaded on activated carbon for efficient removal of Methylene blue: Kinetic and isotherm study of removal process

The objective of this study was to assess and compare the usability of silver and palladium nanoparticles loaded on activated carbon (Ag NPs-AC and/or Pd NPs-AC) for the removal of Methylene blue (MB) molecules from aqueous solutions. Following the optimization of the effect of variables (batch method) including pH, contact time, initial dye concentration and Ag NPs-AC and Pd NPs-AC amounts on MB removal method the kinetic and isotherm studies have been carried out. Based on difference in MB contents (using a UV-vis spectrophotometer) before and after MB adsorption the removal percentage was calculated. The sorption processes followed the pseudo-second-order in addition to intraparticle diffusion kinetic models with good correlation coefficient. The equilibrium experimental data well fitted to the Langmuir models with maximum adsorption capacity of 71.4 and 75.4 mg/g for Ag NPs-AC and Pd NPs-AC, respectively. The obtained results showed that both adsorbents due to their high MB adsorption capacity in short equilibrium times are good alternative as low-cost sorbent in wastewater treatments. (C) 2012 Published by Elsevier B.V.