Improved colorimetric determination of chitosan concentrations by dye binding.

The increasing use of chitosan encourages the search for fast and sensitive methods to quantify its concentrations in water solutions. Recent colorimetric studies have suggested quantification by binding chitosan to Cibacron Brilliant Red 3B-A (BR) dye and measuring the absorbance at 575 nm related to the complex that is formed. This study presents an improved colorimetric technique based on the complexation reaction between BR and chitosan.

Using a Matlab implemented algorithm for UV-vis spectral resolution for pKa determination and multicomponent analysis.

A Matlab implemented computer code for spectral resolution is presented. The code enables the user to resolve the UV-visible absorption spectrum of a mixture of up to 3 previously known components, to the individual components, thus, evaluating their quantities. The resolving procedure is based on searching the combination of the components which yields the spectrum which is the most similar (minimal RMSE) to the measured spectrum of the mixture.

Using the dual-mode model to describe adsorption of organic pollutants onto an organoclay.

Adsorption of 2,4,5-trichlorophenol (TCP) and picric acid (PA) by montmorillonite preloaded with crystal violet (CV) up to 80, 100, and 125% of the cation exchange capacity was studied. The adsorption isotherms indicated a strong interaction of TCP and PA with the organoclay. While the adsorption isotherms of both pollutants can be described by the Langmuir model with relatively good fit, the adsorption of TCP is more adequately described by the dual-mode model (DMM), which combines the Langmuir equation with a partition mechanism.