Determination of the mass transfer limiting step of dye adsorption onto commercial adsorbent by using mathematical models

• Published in: Environmental technology Vol. 35; no. 18; pp. 2356 - 2364
• Main Authors: Marin, Pricila, Borba, Carlos Eduardo, Módenes, Aparecido Nivaldo, Espinoza-Quiñones, Fernando R, de Oliveira, Silvia Priscila Dias, Kroumov, Alexander Dimitrov
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 17.09.2014; Taylor & Francis Ltd
• Subjects: Adsorbents; Adsorption; Applied sciences; Chemical engineering; Coloring Agents - chemistry; Coloring Agents - isolation & purification; Coloring Agents - metabolism; dye; environmental technology; Exact sciences and technology; fixed-bed; Heat and mass transfer. Packings, plates; Industrial Waste; mass transfer; mass transfer mechanism; mathematical modelling; Mathematical models; Models, Theoretical; Pollution; system optimization; Water Pollutants - chemistry; Water Pollutants - isolation & purification; Water Pollutants - metabolism; Water Purification - methods; British Isles; Discoloration; Modeling; Optimization; Mass transfer; Design; dye; Mass transfer coefficient; fixed-bed; mass transfer mechanism; mathematical modelling; Adsorption; Reactive dye; Physicochemical purification; Mathematical model; Fixed bed; Breakthrough curve
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2014.904445

Reactive blue 5G dye removal in a fixed-bed column packed with Dowex Optipore SD-2 adsorbent was modelled. Three mathematical models were tested in order to determine the limiting step of the mass transfer of the dye adsorption process onto the adsorbent. The mass transfer resistance was considered to be a criterion for the determination of the difference between models. The models contained information about the external, internal, or surface adsorption limiting step. In the model development procedure, two hypotheses were applied to describe the internal mass transfer resistance. First, the mass transfer coefficient constant was considered. Second, the mass transfer coefficient was considered as a function of the dye concentration in the adsorbent. The experimental breakthrough curves were obtained for different particle diameters of the adsorbent, flow rates, and feed dye concentrations in order to evaluate the predictive power of the models. The values of the mass transfer parameters of the mathematical models were estimated by using the downhill simplex optimization method. The results showed that the model that considered internal resistance with a variable mass transfer coefficient was more flexible than the other ones and this model described the dynamics of the adsorption process of the dye in the fixed-bed column better. Hence, this model can be used for optimization and column design purposes for the investigated systems and similar ones.