Development of a nanomaterial incorporated with bixin: a sustainable approach for dye removal from aqueous matrices

An environmentally safe technology was developed for the removal of brilliant green (VB) and methylene blue (AM) dyes from aqueous samples. A new nanostructured adsorbent material composed of polycaprolactone polymer (8.00% w/v) and bixin (0.00800% w/v) was manufactured using an electrospinning technical. The best sorption conditions were obtained evaluating the following parameters: deposition time of nanofibers on the support; area of adsorbent; temperature during the adsorption experiments; pH of the reactive medium; adsorption kinect and adsorption isotherm. The highest removal percentage of dyes at the concentration of 20.0 mg kg-1 was obtained in pH = 6.00 at room temperature (25.0ºC) applying the material with nanofibers deposited for 80 minutes with 6.76 cm2 area. The adsorption kinect observed was fast (Figure 1A), reaching the adsorption equilibrium in 2 hours of analyte contact with the adsorbent and the kinect model that best adjusted to the experimental data was pseudo-second order model. The dyes sorption showed to be influenced by the presence of some salts (Na2SO4, NaCl, NaNO3, NH4Cl e CaCl2) suggesting the process occurs by ion exchange mechanism. The material was also applied for AM and VB removal in matrices receiving the raw textile effluent (Figure 1B) and in fish-breeding and shrimp-breeding water (%Emáx of 75 and 90% to AM and VB). With this result, the material proved to be a promising and green adsorbent.