Fast and efficient adsorption of azure (II) on nanoporous MCM-41 for its removal, preconcentration and determination in biological matrices

The objective of the present study was to investigate the potential of nanoporous MCM-41 silicate for the azure (II) adsorption from the aqueous solutions. The method is based on the adsorption of azure (II) after passing on MCM-41 in a column. The adsorption with respect to contact time, pH, flow rate of sample, eluent kind and volume was investigated to provide more information about the adsorption characteristics of MCM-41. After elution of the adsorbed dye, the concentrations of dye were determined by UV–Vis spectrophotometer. The method showed good linearity for the determination of azure (II) in the range of 1–200 ng mL−1 with a regression coefficient of 0.9997. The limit of detection was 0.5 ng mL−1 and the relative standard deviation for 50 ng mL−1 of azure (II) was 1.26 %. The adsorption properties of the MCM-41 were investigated using batch method. In order to investigate the efficiency of adsorption, pseudo-first-order, pseudo-second-order and intra particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Adsorption equilibrium reach within 5 min of contact time and adsorption capacity was found to be 66.0 mg g−1. The method was applied to the determination of azure (II) in river water, broth culture medium and DNA samples.