Adsorption of micropollutants onto fibrous activated carbon: association of ultrafiltration and fibers

1996 ◽  
Vol 34 (9) ◽  
pp. 215-222 ◽  
Author(s):  
C. Brasquet ◽  
J. Roussy ◽  
E. Subrenat ◽  
P. Le Cloirec

The adsorption of polluted solutions is performed by different kinds of activated carbon: grains, powder and fibers (cloth or felt). The adsorption is carried out in a batch reactor. Classic models are applied and kinetic constants are calculated. Results showed that the performance of fiber activated carbon (FAC) is significantly higher than that of granular activated carbon (GAC). Moreover, FAC's adsorption capacities of phenol are greater than GAC's. Therefore the application of FAC adsorbers may lead to smaller adsorption reactors. The breakthrough curves obtained with FAC adsorbers are particularly steep, suggesting a smaller mass transfer resistance than GAC. The adsorption zone in the FAC bed is about 3.4 mm and is not dependent on the flow rate within the range 0.67 - 2.07 m.h−1. The selectivity of the FAC between different size of soluble molecules is shown. Then, an Ultrafiltration (UF) membrane is coupled with FAC to remove successively macromolecules (humic substances) and phenols present together in an aqueous solution. This new and original approach to a water treatment compact process successfully put to use. Industrial developments are put forward.

2006 ◽  
Vol 71 (8-9) ◽  
pp. 957-967 ◽  
Author(s):  
Ljiljana Markovska ◽  
Vera Meshko ◽  
Mirko Marinkovski

The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC) and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II) from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model) combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, two model parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II) concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II) - adsorbent system, k f was constant, except for the lowest initial concentration, while D s was found to increase with increasing initial Zn(II) concentration.


1996 ◽  
Vol 91 (2) ◽  
pp. 187-197 ◽  
Author(s):  
H.M. Ettouney ◽  
A.A. Al-Haddad ◽  
T.M. Abu-Irhayem

1999 ◽  
Vol 39 (10-11) ◽  
pp. 201-205 ◽  
Author(s):  
C. Brasquet ◽  
E. Subrenat ◽  
P. Le Cloirec

Granular activated carbon (GAC) is easily used in water or wastewater treatment in order to remove organic micropollutants. Recently, a new presentation of activated carbon has been developed: fibrous activated carbon in the form of cloth or felt. This work investigates the adsorption onto activated carbon cloths (ACC) of various phenolic compounds from aqueous solution. Experiments were carried out in batch reactors with two ACCs (called CS 1501 and RS 1301) and their performances were compared with those of GAC. Initial adsorption kinetic coefficients were higher with fibers than with granules due to the direct connection of micropores to the external surface of fibers. Adsorption isotherms were also performed and modelized by Langmuir and Freundlich equations. Adsorption capacities were similar or higher with ACCs than with GAC. The behaviour of the ACC CS 1501 was also studied in a dynamic reactor. The breakthrough curves allowed the determination of high maximum adsorption capacities, 117 mg.g−1 for phenol. Pressure drops in ACC beds were measured and the influence of various parameters was shown: the activation step, the number of fabric layers, the space between two layers.


1991 ◽  
Vol 23 (7-9) ◽  
pp. 1659-1666 ◽  
Author(s):  
M. Baudu ◽  
P. Le Cloirec ◽  
G. Martin

Filtration of polluted aqueous solutions is performed by activated carbon membranes. The adsorption capacities are determined in batch reactors. Classic models are applied and kinetic constants are calculated. A comparison with grains and powders of activated carbon is made. The performances of the membranes in continously fed reactors are also studied. The breakthrough curves are plotted for different concentrations of organic compounds and fluid velocities. A simple model of mass transfer into the porous volume of the membrane is put forward and used to predict the outlet concentrations as a function of time. The model parameters are correlated to the fluid velocities and the inlet concentrations.


1987 ◽  
Vol 109 (2) ◽  
pp. 89-93 ◽  
Author(s):  
P. Gandhidasan ◽  
M. Rifat Ullah ◽  
C. F. Kettleborough

Heat and mass transfer analysis between a desiccant-air contact system in a packed tower has been studied in application to air dehumidification employing liquid desiccant, namely calcium chloride. Ceramic 2 in. Raschig rings are used as the packing material. To predict the tower performance, a steady-state model which considers the heat and mass transfer resistances of the gas phase and the mass transfer resistance of the liquid phase is developed. The governing equations are solved on a digital computer to simulate the performance of the tower. The various parameters such as the effect of liquid concentration and temperature, air temperature and humidity and the rates of flow of air and liquid affecting the tower performance have been discussed.


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