Mass transfer models for the adsorption of Acid Red 357 and Acid Black 210 by tannery solid wastes

Diffusional mass transfer models with and without external resistance were applied to represent the adsorption of Acid Red 357 (AR357) and Acid Black 210 (AB210) by tannery solid wastes. The mass transfer parameters, such as, external mass transfer coefficient ( k f ), surface diffusion coefficient ( D s ), and Biot number ( B i ) were estimated and interpreted. It was found that the two models agreed with the experimental data and, very similar values of the parameters were obtained. This indicated that the external mass transfer mechanism can be neglected. Then, the model without external resistance, which is simpler, can be used. The D s values ranged from 5.01 × 10 −13 to 1.30 × 10 −12  m 2  s −1 for AR357 and from 3.19 × 10 −14 to 5.38 × 10 −14  m 2  s −1 for AB210. The high values of the B i number confirmed that the adsorption of AR357 and AB210 on tannery solid wastes was controlled by surface diffusion

Interpretations on the mechanism of In(III) adsorption onto chitosan and chitin: A mass transfer model approach

International audienceOur objective is to develop miniaturised Lab‐on‐a‐Chip (LOC) analysers, for medical diagnostics and for monitoring of the health status of ill persons. The complete system will make use of disposable chip sensors of the size of a credit card and a control unit of the size of a book. The principle of sensors will be based on the determination of the concentration of “protein markers”, which are related to various illnesses. In order to achieve this objective, it is necessary to integrate some optical components in the Chip. In this contribution we describe a successful development of electrophoretic separation LOC with monolithically integrated optics. These optical components are used for the excitation and for the detection of the fluorescence signal from separated bio‐molecules. The developed module can be considered as one of the main building‐block of the completed diagnostic Chip. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim