Methylene blue number as useful indicator to evaluate the adsorptive capacity of granular activated carbon in batch mode: influence of adsorbate/adsorbent mass ratio and particle size.
The adsorption of methylene blue (MB) on three commercial granular activated carbons (GACs), 12 x 40 mesh size, namely Filtrasorb 400, Norit and Picacarb has been researched. A comparative study of adsorptive capacity using the proposed single-point test and the traditional multi-point isotherm test was carried out. For the single-point test, the influence of some parameters such as MB/GACs mass ratio and contact time were evaluated. For this test the adsorptive capacities of the three GACs studied were 319+/-14, 280+/-7 and 260+/-6 mg g(-1) for Filtrasorb 400, Norit and Picacarb, respectively. For multi-point isotherm adsorption test the Langmuir model was used. The parameters involved were obtained by linear and non-linear regression methods. The maximum adsorptive capacity values obtained for both methods were similar and statistically not different than those obtained with the single-point tests. This experimental work also aimed at establishing a relationship between the adsorbent particle size and the adsorptive capacity which could be used complementarily to evaluate the quality of GACs as adsorbents. For a mean particle diameter of 1mm and after 24h of contact time the adsorptive capacity values were 255+/-7, 222+/-7 and 160+/-7 mg g(-1) for Filtrasorb 400, Norit and Picacarb, respectively.
Raposo
F
F
Instituto de la Grasa (CSIC), Seville, Spain. fraposo@cica.es
De La Rubia
M A
MA
Borja
R
R
D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D007700:Kinetics; D008751:Methylene Blue / Q000302:isolation & purification*; D010316:Particle Size; D013696:Temperature; D013816:Thermodynamics
D002606:Charcoal; D008751:Methylene Blue