RETRACTED: Preparation, Kinetics, Thermodynamics, and Mechanism Evaluation of Thiosemicarbazide Modified Green Carboxymethyl Cellulose as an Efficient Cu(II) Adsorbent (Retracted article. See vol. 65, pg. 939, 2020)

Thiosemicarbazide-modified carboxymethyl cellulose adsorbent (TCMC) was synthesized by the oxidation reaction of carboxymethyl cellulose with sodium periodate followed by a condensation reaction with thiosemicarbazide and stabilized with sodium borohydride. TCMC was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). FTIR and XPS analysis successfully shows inclusion of the sulfur and Cu(II) adsorption mechanism onto TCMC. It was also confirmed that the maximum adsorption of Cu(II) ions was achieved by the presence of NH2, OH, and COOH groups. The effects of aldehyde content, pH, time, and concentration of Cu(II) ions were analyzed. Kinetics and error analysis suggested that the pseudo-second-order was best fitted for the adsorption of Cu(II) ions than the other models. The maximum Cu(II) ion adsorption was obtained by the Langmuir model is 144.92 (mg g(-1)) which is greater than the other adsorbents. Furthermore, TCMC also showed a higher regeneration and Cu(II) ion recovery, and the adsorbent can be regenerated without the loss of adsorption efficiency after various adsorption/desorption cycles.