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

Abstract 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 °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.</jats:p

Gamma spectrometry technique application to the 60Co sorption onto IRN-77 resin from radioactive wastewater: Equilibrium, Kinetic and Thermodynamic investigations

The performance of synthetic ion exchange resin IRN-77 have been studied in this work in order to use it as an adsorbent to remove radioactive isotope 60Co from nuclear wastewater by the sorption process, using the gamma spectrometry technique. The resin simple was identified using SEM and FTIR infrared spectrometry. The gamma radiation acquisition emitted from the fixed radioactive 60Co onto IRN-77 solid samples was carried out using the gamma spectrometry chain, equipped with an HPGe semi-conductor detector with high-resolution. Various factors were considered for the sorption process study such as 60Co concentration, contact time and temperature. The maximum adsorption capacity of the IRN-77 samples was determined by studying the adsorption isotherms; Kinetics models including thermodynamics were also studied and investigated. The experimental results showed that the adsorption reaction was adjustable to the pseudo-first-order and the Langmuir model was found to describe best the experimental results by obtaining a very important maximum adsorption quantity of 10.620 µCi of 60Co per 1 gram of IRN-77 adsorbent. A dimensionless separation factor RL was used to judge the favorable adsorption. The adsorption capacity of 60Co ions onto IRN-77 particles increased with the increasing of temperature. The values of the thermodynamic parameters have shown that the 60Co ions adsorption process was endothermic and favored at high temperatures with a positive value of the enthalpy ∆H° of 23,54 kJ/mol. The free energy’s values ∆G◦ are positive over the whole temperature range. The specific activities of the fixed 60Co radionuclide allow evaluating the solid samples IRN-77 resin's sorption capacity