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A new kind of adsorbent graphene oxide nanocomposite (GO–Fe 3 O 4) for removal of Chrysoidine Y was synthesized using the modified Hummers method and co-precipitation. The synthesized GO–Fe 3 O 4 was used as an adsorbent for the removal of Chrysoidine Y from aqueous solution. The effect of initial pH on the adsorption of Chrysoidine Y onto GO–Fe 3 O 4 has been investigated. The adsorption kinetics, isotherm and thermodynamics also have been evaluated. The adsorption was strongly dependent on the pH of medium. The studies on the adsorption revealed that the adsorption process obeyed the Pseudo-second order kinetics model, and the rate-limiting step might be chemical sorption. And the Langmuir isotherm was applicable to describe the adsorption process. This hybrid showed a good performance for the removal of Chrysoidine Y from aqueous solution with an adsorption capacity of 344.83 mg g−1 at room temperature, and could be easily removed from solution using a hand-held magnet in 10 min. Moreover, the adsorption mechanism was discussed and thermodynamic parameters were determined. Thermodynamic parameters indicated that the adsorption process was exothermic and spontaneous. Above all, the removal efficiency of GO–Fe 3 O 4 was still kept at 96.0% when the concentration of dye was 100 mg L−1 in polluted river. This work shows that GO–Fe 3 O 4 is a suitable and efficient adsorbent in the removal of Chrysoidine Y from aqueous solution. [ABSTRACT FROM AUTHOR]

Highlights • Triethanolamine modified CoFe2O4 nanoparticles were first synthesized by a facile one-step method. • This adsorbent can remove Cu (Ⅱ) and MB from solution quickly and efficiently. • It could remove about 85% of Cu (Ⅱ) from industrial wastewater and tap water. • The adsorbent can be reused at least 10 times without any significant variation. Abstract The novel triethanolamine modified magnetic CoFe 2 O 4 nanoparticles (CFO@TEOA) as a magnetic nano-adsorbent have been first synthesized by a facile one-step method for the remove of Cu (II) and methylene blue. Owing to its high saturation magnetization (41.76 emu g−1), CFO@TEOA can be removed from aqueous solution in 1 min by permanent magnet. It exhibits effective adsorption to Cu (II) and methylene blue based on coordination and electrostatic attraction. Adsorption equilibrium can be achieved in 25 min for Cu (II) and 5 min for methylene blue, respectively. The maximum adsorption capacities calculated from Langmuir isotherm are 396.0 mg g−1 for Cu (II) and 301.2 mg g−1 for methylene blue. Additionally, CFO@TEOA keeps its adsorption and desorption efficiencies constant over 10 cycles. More importantly, this nanoadsorbent could removal about 85% of Cu2+and over 98% of methylene blue from real wastewater. This work introduces a high efficient magnetic adsorbent prepared by a one-step route for the removal of Cu (II) ions and methylene blue from aqueous solutions. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract The hierarchically porous carbons were prepared from cellulose by a one-step method and studied as dye-adsorbents using chrysoidine as a model. With the increase of holding temperature, the prepared porous carbons had larger specific surface area and became more effective. Kinetic analysis revealed that adsorption kinetics obeyed the pseudo-second order kinetic model and adsorption equilibrium could reach within 1 h. The studies on isotherm indicated that the adsorption process could be best described by the Langmuir isotherm model and the maximum adsorption capacities was 598.8 mg g−1. Thermodynamic parameters demonstrated that the adsorption process was exothermic and spontaneous. Moreover, the porous carbon could effectively remove some other common dyes. Importantly, the prepared porous carbon was able to remove 98% of chrysoidine from polluted river water and its adsorption efficiency was inappreciably influenced by the water matrix. These results shown that the hierarchically porous carbons synthesized from biomass in this study had a wide application in water treatment. Highlights • Hierarchical porous carbons were prepared from cellulose by a facile way. • Higher holding temperature produced more mesopores and higher adsorption capability. • The adsorbent could effectively remove dyes from aqueous solutions. • Cel-900 could be regenerated five times without obvious loss in removal efficiency. • The method is easily scalable, and likely applicable to other biomass. [ABSTRACT FROM AUTHOR]

A graphene oxide nanocomposite (GO-Fe3O4) was synthesized with a simple and low-cost method. This nanocomposite was characterized by XRD, TEM, FT-IR, TGA, and VSM. Spherical Fe3O4 nanoparticles with an average size of 10 nm were uniformly applied to the surface of graphene oxide sheets. GO-Fe3O4 nanocomposite showed a superparamagnetic characteristic at room temperature and its saturation magnetization was 8.5 A · M2/kg. The adsorption behaviour of diquat at the surface of GO-Fe3O4 was investigated, including effects of pH, temperature, and water matrix. The adsorption kinetics, thermodynamics, and adsorption isotherm were also examined. The adsorption was strongly dependent on pH. The adsorption process obeyed the pseudo-second order kinetic model, and the rate-determining step might be chemical sorption. The Langmuir adsorption isotherm model was applicable for describing the adsorption of diquat onto GO-Fe3O4, and the adsorption capacity was 74.85 mg/g at room temperature. Thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. Most importantly, the GO-Fe3O4 could remove 96.6 % of diquat from a real water sample when the concentration of diquat is 20 mg/L. [ABSTRACT FROM AUTHOR]

Abstract: An amino-functionalized magnetic nano-adsorbent (MNPs-NH2) has been prepared by a simple one-pot method for the removal of Pb (II). These amino-functionalized Fe3O4 nano-particles showed a high adsorption capacity and efficient adsorption toward Pb (II) in an aqueous medium. The studies on the adsorption of Pb (II) ions revealed that the process obey the pseudo-second order kinetic model, the determining step might be chemical sorption. Among the various isotherm models, the experimental data for the adsorption of Pb (II) were found to follow the Langmuir isotherm and the maximum adsorption capacity was 40.10mgg−1 at pH 5 and 298K. The sorption mean free energy from the Dubinin–Radushkevich isotherm was found to be 10.31kJmol−1, indicating a chemical sorption. In addition, Pb (II) ions could be desorbed from nano-adsorbents and the MNPs-NH2 exhibited a good reusability. Importantly, about 98% of Pb (II) could be removed by MNPs-NH2 from industrial wastewater and tap water. [Copyright &y& Elsevier]

[Display omitted] • A visible light-enhanced 0.6 %GO-FSNT was developed for removing of phenanthrene. • The high degradation rate is obtained by using a less amount of catalyst within a shorter time. • The phenanthrene adsorbed on the GO while the water adhered to N-TiO 2 shell. • A small amount of GO facilitates charge separation and visible light utilization. • The photoinduced hydrophilicity contributes to the increase of photodegradation rate. One kind of novel magnetically separable graphene-based titanium dioxide photocatalytic nano-adsorbents (GO-FSNTs) were prepared for the adsorption-photodegradation of phenanthrene under visible light. The GO-FSNTs displayed the high adsorption-photodegradation efficiency and 10 mg of 0.6% GO-FSNT (wt%) can remove 94.9% of phenanthrene within 4 h. The introduction of a small amount of GO enables 0.6% GO-FSNT to selectively adsorb phenanthrene through the π-π interaction, reduce the light-shielding effect and improve separation of photogenerated carriers effectively. Meanwhile, the N-TiO 2 shell is occupied by adsorbed water molecules which can spontaneously repair lattice oxygen. Furthermore, the more hydrophilic surface of 0.6% GO-FSNT is formed by increased photoinduced hydroxyl groups under visible light during photodegradation. The photoinduced hydroxyl groups can further generate OH and improve photocatalytic activity. The degradation pathway of phenanthrene was proposed based on intermediates analysis and density functional theory calculations. This work helps to reveal the relationship between the adsorption-photodegradation and the photoinduced hydrophilicity. [ABSTRACT FROM AUTHOR]