Tesis doctoral de Zoraida Del Carmen Zeledon Toruño
Adsorption by activated carbons is a treatment widely used for the efficiency of the method to eliminate significant amounts of polluting agents. With the purpose of reducing the costs of the current treatments, in this study, the potential of the adsorbent leonardite as a natural and low cost material, has been evaluated for reduction of heavy metals and polycyclic aromatic hydrocarbons (pahs) in aqueous solutions. The effect of factors such as ph, contact time, concentration and hardness of the metallic solution on adsorption has been studied. In addition, comparative experiments of adsorption capacity of leonardite with other alternative materials and widely used commercial activated carbon has been carried out. Previously to the adsorption studies, a physic-chemical characterization of the material has been performed. The results show that leonardite has heterogeneous nature, acid character and has high capacity of ion exchange provided by interchange among the h+ ions of carboxylic and phenolic functional groups. It has been demonstrated that ph has a significant influence upon adsorption of ni, cu, zn, cd and pb. The best results were obtained in the rank of ph 5-6. In the study of contact time has been observed that all the metals reach maximum levels of retention after two hours. These data have been fitted with three kinetic models: lagergren, pseudo-second order and hyperbolic. Of these models, pseudo-second order adjusts best to the data. The kinetic constant or transference coefficient determined with the pseudo-second order model for each metal has shown to depend on the concentration, nature of solute and adsorbent as well as of contact time. The maximum adsorption capacity of each metal has been determined varying the concentration of the metal and maintaining constant the dose of adsorbent (1 g/l). The obtained experimental data adjust to langmuir and extended langmuir (for a binary system) isotherms. According to the results, the decreasing order of
Datos académicos de la tesis doctoral «Estudio de adsorcion de metales pesados e hidrocarburos aromaticos policiclicos mediante leonardita«
- Título de la tesis: Estudio de adsorcion de metales pesados e hidrocarburos aromaticos policiclicos mediante leonardita
- Autor: Zoraida Del Carmen Zeledon Toruño
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 19/12/2006
Dirección y tribunal
- Director de la tesis
- Concepcion Lao Luque
- Tribunal
- Presidente del tribunal: xavier Querol carceller
- raimund Haberl (vocal)
- José Luis Cortina pallas (vocal)
- isabel Villaescusa gil (vocal)