Effective removal of Cobalt(II) ions from aqueous solutions and nuclear industry wastewater using sulfhydryl and carboxyl functionalised magnetite nanocellulose composite: batch adsorption studies
Creators: name: T. S. Anirudhan
name: F. Shainy
name: J. R. Deepa
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: FOS: Physical sciences
subject: Medicine
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: FOS: Biological sciences

description: A new adsorbent sulfhydryl and carboxyl functionalized magnetite nanocellulose composite [(MB-IA)-g-MNCC] was synthesized by graft co-polymerization of itaconic acid onto magnetite nanocellulose (MNCC) using EGDMA as cross linking agent and K<sub>2</sub>S<sub>2</sub>O<sub>8</sub> as free radical initiator. The adsorption occurs maximum in the pH 6.5. The best fitted kinetic model was found to be pseudo-second-order kinetics. Therefore the mechanism of Co(II) adsorption onto (MB-IA)-g-MNCC follows ion exchange followed by complexation. The Langmuir model was the best fitted isotherm model for the adsorption of Co(II) onto the (MB-IA)-g-MNCC. Simulated nuclear power plant coolant water samples were also treated with (MB-IA)-g-MNCC to demonstrate its efficiency for the removal of Co(II) from aqueous solutions in the presence of other metal ions. To recover the adsorbed Co(II) ions and also to regenerate the adsorbent to its original state 0.1 M HCl was used as suitable desorbing agent. Six cycles of adsorption-desorption experiments were conducted and was found that adsorption capacity of (MB-IA)-g-MNCC has been decreased from 97.5% in the first cycle to 84.7% in the sixth cycle. Recovery of Co(II) using 0.1 M HCl decreased from 93.2% in the first cycle to 79.3% in the sixth cycle. <b>Abbreviations:</b> T: absolute temperature; q<sub>e</sub>: amount adsorbed at equilibrium; q<sub>t</sub>: amount adsorbed at time t; CELL: cellulose; Co: cobalt; C<sub>e</sub>: concentration at equilibrium; C<sub>HCl</sub>: concentration of HCl; C<sub>NaOH</sub>: concentration of NaOH; C<sub>A</sub>: concentrations of acid; C<sub>B</sub>: concentrations of base; W<sub>g</sub>: dry weight of composite; W<sub>i</sub>: dry weight of MNCC; DS: energy dispersive spectra; EGDMA: ethylene glycol dimethacrylate; Ce: equilibrium concentration; K<sub>L</sub>: equilibrium constant; F: Faradays constant; FTIR: Fourier transform infrared spectra; ΔG<sup>o</sup>: free energy change; K<sub>F</sub>: Freundlich adsorption capacity; 1/n: Freundlich constant; R: gas constant; D: grafting density; EC<sub>o</sub>: initial concentration; IA: itaconic acid; IA-g-MNCC: itaconic acid-grafted-magnetite nanocellulose composite; b: Langmuir constant; MNCC: magnetite nanocellulose composite; Q<sup>0</sup>: Maximum adsorption capacity; (MB-IA)-g-MNCC: 2-mercaptobenzamide modified itaconic acid-grafted-magnetite nanocellulose composite; NC: nanocellulose; pH<sub>pzc</sub>: Point of zero charge; K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>: potassium peroxy sulphate; k<sub>1</sub>: pseudo-first-order rate constant; k<sub>2</sub>: pseudo-second-order rate constant; SEM: scanning Electron Microscope; b<sub>s</sub>: Sips adsorption capacity; Q<sub>s</sub>: Sips maximum adsorption capacity; ΔH°: standard enthalpy change; ΔS°: standard entropy change; A: surface area; σ<sub>0</sub>: surface charge density; 1/n<sub>s</sub>: surface heterogeneity factor; VSM: vibrating sample magnetometer; V: volume of solution; W: weight of (MB-IA)-g-MNCC; M<sub>composite</sub>: weight of the composite; XRD: X-ray diffraction