Dinamica de processos de sorpcao: Separacao por bombagem parametrica e recuperacao de metais com resinas complexantes

Abstract

The present work is divided in two parts: Adsorptive Parametric Pumping and Recovery of Metals by Chelating Ion Exchange Resins. First, the experimental set-up of a completely automated pilot plant for recuperative parametric pumping is described. The column and the ancillary equipment, the product receivers, the sampling, collector and analytical devices are reported. Moreover the automation of the entire unit is also discussed. Parameters related with adsorption equilibrium, mass transfer and heat transfer resistances were determined in order to obtain basic information to simulate the process behaviour. Adsorption equilibrium data for the system phenol-water/Duolite Es-861, at 20 and 60 deg C, were measured in batch experiments. Data were well fitted by the Langmuir equation. In order to evaluate the mass transfer resistances, experimental breakthrough curves, at 20 and 60 deg C, were reasonably predicted by a model that considers axial dispersed plug flow, intra particle diffusion and film mass transfer. A tortuosity factor was estimated, #tau#_p=3. Fixed bed hydrodynamic conditions, by using the tracer technique, have also been studied and led to Pe = 120. Several thermal runs were carried out to get axial (K_a_e) and radial (K_r_e) conductivities and the wall heat coefficient (H_w_e). The prediction with a bidimensional pseudo homogeneous model allowed us to find the following values: K_r_e=3.5x10"-"4 cal / cm deg C s, K_a_e=6.4x10"-"2 cal / cm deg C s and h_w_e=5.8x10"-"4 cal /cm"2 deg C s. Several experiments were ran by operating the recuperative parametric pumping plant. Previously, computer simulations were done to get a feeling about the operating conditions more relevant in the process. A model derived from differential mass and heat balances, including equilibrium relationships, external balances, initial and boundary conditions, was tested to predict experimental parametric pumping runs. A reasonable agreement was obtained between simulated and experimental results. Since our main purpose was the purification of phenolic wastewater, optimal operating conditions yielding the maximum productivity of the bottom product (with a low phenol concentration..Available from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1249-074 Lisboa, Portugal / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga