Preparation of novel multi-walled carbon nanotubes nanocomposite adsorbent via RAFT technique for the adsorption of toxic copper ions.

In the present work, polymer-coated multiwalled carbon nanotube (MWCNT) was prepared via RAFT method. First, a novel trithiocarbonate-based RAFT agent was prepared attached chemically into the surface of MWCNT. In addition, the RAFT co-polymerization of acrylic acid and acrylamide monomers was conducted through the prepared RAFT agent. In the next age, the surface morphology and chemical properties of the prepared components were fully examined by using FTIR, 1HNMR, SEM, TEM, XRD and TGA/DTG techniques. Finally, the modified MWCNT composite was employed as an excellent adsorbent for the adsorption of copper (II) ions. The results indicated that ion adsorption basically relies on adsorbing time, solution pH, initial copper concentration, and adsorbent dosage. Further, the adsorption kinetics and isotherm analysis demonstrated that the adsorption mode was fitted with the pseudo-second-order and Langmuir isotherm models, respectively. Based on the results of thermodynamic study, the ion adsorption process was endothermic and spontaneous. Finally, based on the experimental results, the surface functionalized MWCNT with hydrophilic groups could be successfully used as a promising selective adsorbent material in wastewater treatment.

Effective removal of copper from aqueous solutions by modified magnetic chitosan/graphene oxide nanocomposites.

In the present work, a novel magnetic chitosan/graphene oxide nanocomposite (MCGON) was synthesized for the removal of Cu2+ from aqueous solutions. The adsorbent was composed of graphene oxide (GO) modified by ethylenediamine (ED), Fe3O4 nanoparticles and chitosan-g-poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) copolymer. The composition and structure of adsorbents were characterized by FTIR, SEM, EDX, XRD, TGA, VSM and BET analysis. The magnetic MCGON with a high specific surface area of (132.9m2g-1), large pore volume (4.03cm3g-1), small particle size (15nm) and strong saturation magnetization (3.82emug-1) was used as an efficient adsorbent for the removal of Cu2+ ions from wastewater. The results showed that the adsorption of Cu2+ onto MCGON exhibited a maximum adsorption capacity of 217.4mgg-1. Kinetics, thermodynamics and equilibrium isotherm of the removal of copper (II) ions were carefully investigated. Adsorption of Cu2+ onto nanocomposite followed pseudo-second-order and Langmuir isotherm models. Thermodynamic parameters exhibited that the sorption process was feasible, spontaneous and endothermic in nature. These results provide evidences for the efficient removal of heavy metals from industrial wastewater.

Fabrication of starch-graft-poly(acrylamide)/graphene oxide/hydroxyapatite nanocomposite hydrogel adsorbent for removal of malachite green dye from aqueous solution.

This article reports the efficient removal of malachite green (MG) dye from aqueous solution using a novel polysaccharide-based nanocomposite hydrogel adsorbent (NHA). The NHAs of different compositions were prepared through a simple free radical graft copolymerization of acrylamide (AM) monomer onto starch backbones in the presence of graphene oxide (GO) nano sheets and nono-hydroxyapatite (n-HAp). The surface morphology and chemical properties of the prepared NHAs were fully examined by using FTIR, SEM, TEM, XRD and TGA. The biocompatibility, biodegradability, porosity, water content and water uptake of the synthesized NHAs were also evaluated. The NHA was employed as bioadsorbents for the adsorption of MG dye. The temperature dependence data also revealed that MG sorption process was feasible, spontaneous and endothermic. The MG adsorption rates were described by the pseudo-second-order model. Furthermore, the adsorption isotherm data fitted well with the Langmuir isotherm model with a maximum adsorption capacity of 297mgg-1 for MG dye. The NHA also showed an excellent regeneration capacity after five consecutive cycles of dye adsorption-desorption. According to the results, the prepared NHAs could be environment friendly and promising adsorbents for the adsorption of different cationic dyes from contaminated water.