Equilibrium and kinetic studies on the removal of Cu(II) from aqueous solution using acid treated modified rice husk: A Comparative Study

This study deals with the removal of Cu(II) using rice husk and its acid treated modified form as adsorbents under batch experiments. Different parameters have been investigated for the adsorption of copper metal. Equilibrium time for copper adsorption was found 90 minutes. Maximum percentage for removal of Cu(II) was found at pH=4 in both raw form of rice husk and its treated form. Percentage removal of copper metal was up to 90% for treated rice husk and up to 70% for raw form of rice husk. It could be concluded that the removal efficiency was enhanced by increasing wastewater initial concentration in the first percentage of adsorption and then decreased due to saturation of rice husk particles. Also according to achieved results, calculated saturation capacity in per gram rice husk for Cu(II) were 36.587 and 45.267 mg/g from raw rice husk and treated form of rice husk respectively. The amount of Cu(II) adsorbed increased with increase in their contact time. The rate of reaction was fast. So that 20–30 min after the start of the reaction, between 40 and 50 % of metal ions were removed. The pseudo second order kinetic model provided the best correlation of the used experimental data compared to the pseudo first model with a R2 of 0.984 and 0.979 for raw rice husk and treated form of rice husk respectively.