Polyacrylonitrile-based fiber modified with thiosemicarbazide by microwave irradiation and its adsorption behavior for Cd(II) and Pb(II)

Abstract

A novel thiosemicarbazide modified adsorbent (PAN(MW)-TSC) based on polyacrylonitrile fiber was successfully synthesized under microwave irradiation, which was applied for the uptake of Cd(II) and Pb(II) from aqueous solution subsequently. Microwave irradiation method is a new approach to achieve the modification and it turns out that just a 30min process is enough for the anchoring of functional groups in the fiber matrix. The surface characterization was performed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) elemental analysis (EA) and thermogravimetric analysis (TGA), indicating that the modification was successfully accomplished. Batch adsorption experiments including equilibrium isotherms, kinetics and the effects of pH and temperature on the adsorption of Cd(II) and Pb(II) were systematically studied. Among three kinetic models, the pseudo-second-order kinetic model provides the best correlation for the process. The nonlinear resolution of the Langmuir isotherm equation has been found to show the closest fit to the equilibrium date. Thermodynamic parameters, involving △G, △H and △S were also calculated from graphical interpretation of the experimental data, which suggest that metal ions adsorption onto PAN(MW)-TSC fibers is spontaneous and exothermic. Regeneration of PAN(MW)-TSC fibers loaded with metal ions was efficiently done with 0.5M HNO3, by which the investigated adsorbent could be used reproductively for five times with a small decrease in sorption capacity. The feasible preparation of PAN(MW)-TSC fibers with high adsorption capacities opens a new perspective in the potential application for wastewater treatment.

Removal of cadmium(II) cations from an aqueous solution with aminothiourea chitosan strengthened magnetic biochar

“…After the MBC was modified further with TC–CS, in the resulting TMBC spectrum, the broad band centered on around 3450 cm −1 was strengthened; this was associated with the OH stretching vibrations of the hydroxyl groups in the pyranose rings or the adsorbed water molecules . The appearance of CH asymmetric and symmetric stretching vibrations around 2900 cm −1 , the two new peaks at about 1545 and 1250 cm −1 , were attributed to the CS bonds of the thiourea group stretching vibrations; this confirmed the occurrence of TC–CS in the TMBC sample structure.…”

Adsorption mechanism modeling using lead (Pb) sorption data on modified rice bran-insoluble fiber as universal approach to assess other metals toxicity

“…These results were in accordance with the findings of other researchers who also found the Langmuir model was the best when studied the adsorption of metal ions on fibers or biomaterials. [40][41][42] Further, the Langmuir constant b indicator of binding affinity increased with increasing temperature, suggesting the enhanced sorption capacity of Pb 2+ with RBIF at a higher temperature. On the other hand, E values generated using Dubinin-Radushkevich (D-R) model (8 kJ/mol, 25-37 • C) confirmed the physical sorption behavior of Pb 2+ with RBIF (Table 5).…”

Modified polyacrylonitrile fiber as a renewable heterogeneous base catalyst for Henry reaction and Gewald reaction in water

“…The thermal stabilities of different fiber catalysts have been performed and compared, and the results are given in Figure . The PANF exhibited two main transient of weight loss at 309 and 390 °C which were ascribed degradation of the CN and PANF backbone, respectively (Figure S3) . The decomposing rate of the C‐PANF is slower than that of PANF and the main thermal decomposition temperature is 307 °C [Figure (a)].…”