Recovery of recycled paper in the removal of the textile dye basic yellow 28: characterization and adsorption studies

A recycled newspaper pulp (NPP) was used in the adsorption of a basic textile dye (Sandocryl gold yellow, basic yellow 28: BY28). NPP was deinked and bleached for the homogeneity of the adsorbent and elimination of the anchor. The release of NPP was followed by measuring the absorbance and chemical oxygen demand (COD) in water. The NPP samples were characterized by X-ray diffraction and FT-IR spectroscopy while the morphology was visualized by the SEM technique and the chemical composition determined by the energy dispersive spectroscopy (EDS). The adsorption of BY28 on NPP was investigated by varying the contact time (0-160 min), pH (2-6), biosorbent dose (1-8 g) and initial BY28 concentration (25-200 mg L-1); the results show a good yield in the pH range (4-7). The adsorption isotherms were studied by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Tempkin models. A maximal NPP adsorption capacity of 91.21 mg g(-1)at 20 degrees C was obtained. The kinetic study showed that the best fit is obtained with the pseudo second order model that correlates suitably the experimental data well.