Nanosized magnetite has emerged as an adsorbent of pollutants in water remediation. Nanoadsorbents include magnetic iron oxide and its modifiers/stabilizers, such as carbon, silica, clay, organic moieties (polymers, aminoacids, and fatty acids) and other inorganic oxides. This review is focused on the recent developments on the synthesis and use of magnetic nanoparticles and nanocomposites in the treatment of contaminated water. The emphasis is on the influence of the iron oxide modifiers on some properties of interest such as size, BET area, and magnetization. The characteristics of these nanomaterials are related to their ability to eliminate heavy metal ions and dyes from wastewater. Comparative analysis of the actual literature was performed aiming to present the magnetic material, its preparation methodology and performance in the elimination of the selected pollutants. Vast information has been properly summarized according to the materials, their properties and preferential affinity for selected contaminants. The mechanisms governing nanomaterial’s formation as well as the interactions with heavy metals and dyes have been carefully analyzed and associated to their efficiency. 相似文献
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 K2S2O8 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.
Abbreviations: T: absolute temperature; qe: amount adsorbed at equilibrium; qt: amount adsorbed at time t; CELL: cellulose; Co: cobalt; Ce: concentration at equilibrium; CHCl: concentration of HCl; CNaOH: concentration of NaOH; CA: concentrations of acid; CB: concentrations of base; Wg: dry weight of composite; Wi: dry weight of MNCC; DS: energy dispersive spectra; EGDMA: ethylene glycol dimethacrylate; Ce: equilibrium concentration; KL: equilibrium constant; F: Faradays constant; FTIR: Fourier transform infrared spectra; ΔGo: free energy change; KF: Freundlich adsorption capacity; 1/n: Freundlich constant; R: gas constant; D: grafting density; ECo: initial concentration; IA: itaconic acid; IA-g-MNCC: itaconic acid-grafted-magnetite nanocellulose composite; b: Langmuir constant; MNCC: magnetite nanocellulose composite; Q0: Maximum adsorption capacity; (MB-IA)-g-MNCC: 2-mercaptobenzamide modified itaconic acid-grafted-magnetite nanocellulose composite; NC: nanocellulose; pHpzc: Point of zero charge; K2S2O8: potassium peroxy sulphate; k1: pseudo-first-order rate constant; k2: pseudo-second-order rate constant; SEM: scanning Electron Microscope; bs: Sips adsorption capacity; Qs: Sips maximum adsorption capacity; ΔH°: standard enthalpy change; ΔS°: standard entropy change; A: surface area; σ0: surface charge density; 1/ns: surface heterogeneity factor; VSM: vibrating sample magnetometer; V: volume of solution; W: weight of (MB-IA)-g-MNCC; Mcomposite: weight of the composite; XRD: X-ray diffraction 相似文献