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Xiangke Wang - One of the best experts on this subject based on the ideXlab platform.

  • preparation of molybdenum disulfide coated mg al layered double hydroxide composites for efficient removal of chromium vi
    ACS Sustainable Chemistry & Engineering, 2017
    Co-Authors: Jing Wang, Xiangxue Wang, Pengyi Wang, Huihui Wang, Junfei Dong, Wanying Chen, Suhua Wang, Tasawar Hayat, Ahmed Alsaedi, Xiangke Wang
    Abstract:

    With the rapid development of industry, heavy metal pollution has become a potential hazard to public health and the ecological system. Herein, molybdenum disulfide coated Mg/Al layered double hydroxide composites (LDHs@MoS2) were prepared via a simple hydrothermal method and applied for the adsorption of Cr(VI) from a water solution. The removal capacity of Cr(VI) on LDHs@MoS2 reached 76.3 mg/g at pH = 5.0, and the removal Process relied on ionic strength and pH. The results confirmed that the uptake of Cr(VI) on LDHs@MoS2 followed a spontaneous Endothermic Process. In contrast to the LDHs, LDHs@MoS2 showed excellent chemical stability, which was beneficial for practical applications. Specifically, the coexisting ions had little influence on the uptake of Cr(VI). The interaction of Cr(VI) with the LDHs@MoS2 composites was mainly controlled by electrostatic attraction and outer-sphere surface complexation. The findings can provide new insights into the uptake of heavy metal ions in a natural aquatic envir...

  • preparation of montmorillonite carbon composite and its application for u vi removal from aqueous solution
    Applied Surface Science, 2015
    Co-Authors: Xiangke Wang, Rui Zhang, Changlun Chen
    Abstract:

    Abstract The montmorillonite@carbon (MMT@C) composite was synthesized by the one-step hydrothermal carbonization Process. U(VI) sorption on MMT@C from aqueous solution was investigated by using batch experiments. The maximum capacity of MMT@C toward U(VI) was 20.76 mg g −1 at pH 3.95, which was much higher than that of the raw MMT. The decoration of the functional carbonaceous species on the MMT@C improved its sorption capacity. U(VI) sorption on the MMT@C was an Endothermic Process. The inner-sphere surface complexation might be the primary sorption mechanism. MMT@C was a promising material for pre-concentration and immobilization of U(VI) from large volumes of aqueous solution.

  • plasma induced grafting of polyacrylamide on graphene oxide nanosheets for simultaneous removal of radionuclides
    Physical Chemistry Chemical Physics, 2015
    Co-Authors: Xiangke Wang, Wencheng Song, Xiangxue Wang, Qi Wang, Dadong Shao
    Abstract:

    Polyacrylamide (PAM) grafted graphene oxide (denoted as PAM/GO) was synthesized by the plasma-induced polymerization technique and applied as an adsorbent for the simultaneous removal of radionuclides from radioactive wastewater. The interactions of PAM/GO with the radionuclides U(VI), Eu(III) and Co(II) were studied, along with their sorption kinetics. The results indicated that radionuclide sorption on PAM/GO was affected by the solution pH and ionic strength. The maximum sorption capacities of U(VI), Eu(III) and Co(II) on PAM/GO (0.698, 1.245 and 1.621 mmol g−1, respectively) at pH = 5.0 ± 0.1 and T = 295 K were much higher than those of radionuclides on GO and other adsorbents. The thermodynamic data (ΔH0, ΔS0 and ΔG0) calculated from the temperature-dependent sorption isotherms suggested that the sorption of radionuclides on PAM/GO was a spontaneous and Endothermic Process. These results indicate that PAM/GO is a promising material for the control of radionuclide pollution.

  • kinetic and thermodynamic study of 1 naphthol adsorption from aqueous solution to sulfonated graphene nanosheets
    Chemical Engineering Journal, 2011
    Co-Authors: Guixia Zhao, Xiangke Wang
    Abstract:

    Abstract The sulfonated graphene nanosheets were prepared from graphene oxides. The kinetic and thermodynamic adsorption of 1-naphthol from aqueous solution on the sulfonated graphene nanosheets were investigated under ambient conditions. The results of 1-naphthol kinetic adsorption on sulfonated graphene indicated that the adsorption was inclined to stack on the surface of graphene nanosheets with low activation energy. The thermodynamic parameters calculated from the temperature dependent adsorption isotherms indicated that the adsorption was a spontaneous and Endothermic Process, and the adsorption was in good agreement with the theory of non-bonding interaction intensity. The adsorption capacities of 1-naphthol on sulfonated graphene nanosheets are ∼2.3 mmol/g at 293.15 K, and ∼6.4 mmol/g at 313.15 and 333.15 K, which are the highest adsorption capacity of todays’ nanomaterials. The results suggest that the sulfonated graphene nanosheets may be a promising suitable candidate for the preconcentration of 1-naphthol from large volume of aqueous solutions in real work in near future.

  • effect of environmental conditions on pb ii adsorption on β mno2
    Chemical Engineering Journal, 2010
    Co-Authors: Donglin Zhao, Changlun Chen, Xin Yang, Hui Zhang, Xiangke Wang
    Abstract:

    In this study, the adsorption of Pb(II) on β-MnO2 as a function of various environmental conditions such as contact time, pH, ionic strength, humic acid (HA)/fulvic acid (FA), and temperature was investigated using batch techniques. The results indicated that the adsorption of Pb(II) on β-MnO2 was obviously dependent on pH but independent of ionic strength. The presence of HA/FA enhanced the adsorption of Pb(II) on β-MnO2 at low pH, whereas reduced Pb(II) adsorption on β-MnO2 at high pH. The kinetic adsorption of Pb(II) on β-MnO2 can be well fitted by the pseudo-second-order rate equation. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were also calculated from the temperature dependent adsorption isotherms, and the results suggested that the adsorption of Pb(II) on β-MnO2 was a spontaneous and Endothermic Process. The adsorption of Pb(II) on β-MnO2 was attributed to surface complexation rather than ion exchange.

Augustine E Ofomaja - One of the best experts on this subject based on the ideXlab platform.

  • effect of temperatures and ph on methyl violet biosorption by mansonia wood sawdust
    Bioresource Technology, 2008
    Co-Authors: Augustine E Ofomaja
    Abstract:

    In this study, the effect of temperature on the equilibrium biosorption of methyl violet dye from aqueous solution using Mansonia wood sawdust was studied. The equilibrium biosorption data were analyzed using three widely applied isotherm models; Langmuir, Freundlich and Redlich-Peterson isotherm. The fit of three linear Langmuir isotherm forms, the Freundlich isotherm, and the Redlich-Peterson isotherm were determined using linear and the non-linear methods. Langmuir isotherm parameters obtained from the three Langmuir linear equations by using linear method were dissimilar, except, when the non-linear method was used. Best fits were yielded with Langmuir and Redlich-Peterson isotherms. The methyl violet biosorption was strongly dependent solution pH and percentage dye removal became significant above pH 7, which was slightly higher than the pH(PZC) of the sawdust material. In addition, various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees , and DeltaS degrees were calculated. Results suggested that the biosorption was a spontaneous and Endothermic Process.

  • Effect of temperatures and pH on methyl violet biosorption by Mansonia wood sawdust
    Bioresource Technology, 2008
    Co-Authors: Augustine E Ofomaja
    Abstract:

    In this study, the effect of temperature on the equilibrium biosorption of methyl violet dye from aqueous solution using Mansonia wood sawdust was studied. The equilibrium biosorption data were analyzed using three widely applied isotherm models; Langmuir, Freundlich and Redlich–Peterson isotherm. The fit of three linear Langmuir isotherm forms, the Freundlich isotherm, and the Redlich–Peterson isotherm were determined using linear and the non-linear methods. Langmuir isotherm parameters obtained from the three Langmuir linear equations by using linear method were dissimilar, except, when the non-linear method was used. Best fits were yielded with Langmuir and Redlich–Peterson isotherms. The methyl violet biosorption was strongly dependent solution pH and percentage dye removal became significant above pH 7, which was slightly higher than the pHPZC of the sawdust material. In addition, various thermodynamic parameters, such as ΔG°, ΔH°, and ΔS° were calculated. Results suggested that the biosorption was a spontaneous and Endothermic Process.

Fuat Guzel - One of the best experts on this subject based on the ideXlab platform.

  • removal of copper nickel cobalt and manganese from aqueous solution by kaolinite
    Water Research, 2003
    Co-Authors: Omer Yavuz, Yalcin Altunkaynak, Fuat Guzel
    Abstract:

    The removal of some heavy metals such as Mn(II), Co(II), Ni(II), and Cu(II) from aqueous solution is studied using a raw kaolinite. The sorption of these metals on kaolinite conformed to linear form of Langmuir adsorption equation. Langmuir C(m) constants for each metal were found as 0.446 mg/g (Mn), 0.919 mg/g (Co), 1.669 mg/g (Ni), 10787 mg/g (Cu) at 25 degrees C, respectively. Also, kinetic and thermodynamic parameters such as enthalpy (deltaH), free energy (deltaG) and entropy (deltaS) were calculated and these values show that adsorption of heavy metal on kaolinite was an Endothermic Process and the Process of adsorption was favoured at high temperatures.

  • removal of copper nickel cobalt and manganese from aqueous solution by kaolinite
    Water Research, 2003
    Co-Authors: Omer Yavuz, Yalcin Altunkaynak, Fuat Guzel
    Abstract:

    Abstract The removal of some heavy metals such as Mn(II), Co(II), Ni(II), and Cu(II) from aqueous solution is studied using a raw kaolinite. The sorption of these metals on kaolinite conformed to linear form of Langmuir adsorption equation. Langmuir C m constants for each metal were found as 0.446 mg/g (Mn), 0.919 mg/g (Co), 1.669 mg/g (Ni), 10,787 mg/g (Cu) at 25°C, respectively. Also, kinetic and thermodynamic parameters such as enthalpy (Δ H ), free energy (Δ G ) and entropy (Δ S ) were calculated and these values show that adsorption of heavy metal on kaolinite was an Endothermic Process and the Process of adsorption was favoured at high temperatures.

Mika Sillanpää - One of the best experts on this subject based on the ideXlab platform.

  • Recovery of Gold from Chloride Solution by TEMPO-Oxidized Cellulose Nanofiber Adsorbent
    Sustainability, 2019
    Co-Authors: Shila Jafari, Minna Hakalahti, Eero Kontturi, Tekla Tammelin, Benjamin P. Wilson, Mari Lundström, Mika Sillanpää
    Abstract:

    The goal of this study was to assess the sustainability of a modified cellulose nanofiber material for the recovery of precious gold from chloride solution, with a special focus on gold recovery from acidic solutions generated by cupric and ferric chloride leaching Processes. TEMPO-oxidized cellulose nanofiber in hydrogel (TOCN), dry (H-TOCN, F-TOCN) and sheet form (S-TOCN) was examined for gold adsorptivity from chloride solution. Additionally, this work describes the optimum conditions and parameters for gold recovery. The data obtained in this investigation are also modeled using kinetic (pseudo first-order and pseudo second-order), isotherm best fit (Freundlich, Langmuir and Langmuir-Freundlich), and thermodynamic (Endothermic Process) parameters. Results demonstrate that high levels of gold removal can be achieved with TEMPO-oxidized cellulose nanofibers (98% by H-TOCNF) and the interaction characteristics of H-TOCN with gold suggests that other precious metals could also be efficiently recovered.

Donglin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • effect of ph ionic strength and humic substances on the adsorption of uranium vi onto na rectorite
    Journal of Radioanalytical and Nuclear Chemistry, 2011
    Co-Authors: Donglin Zhao, Shubin Yang, Shaohua Chen, Zhiqiang Guo, Xin Yang
    Abstract:

    In this study, the adsorption of U(VI) from aqueous solution on Na-rectorite was studied as a function of various environmental conditions such as contact time, pH, ionic strength, soil humic acid (HA)/fulvic acid (FA), solid contents, and temperature under ambient conditions by using batch technique. The kinetic adsorption is fitted by the pseudo-second-order model very well. The adsorption of U(VI) on Na-rectorite was strongly dependent on pH and ionic strength. A positive effect of HA/FA on U(VI) adsorption was found at low pH, whereas a negative effect was observed at high pH. The presence of HA/FA enhanced the U(VI) adsorption at low pH values, but reduced U(VI) adsorption at high pH. The thermodynamic parameters (ΔH 0, ΔS 0, and ΔG 0) were also calculated from the temperature dependent adsorption isotherms, and the results suggested that the adsorption of U(VI) on Na-rectorite was a spontaneous and Endothermic Process.

  • effect of environmental conditions on pb ii adsorption on β mno2
    Chemical Engineering Journal, 2010
    Co-Authors: Donglin Zhao, Changlun Chen, Xin Yang, Hui Zhang, Xiangke Wang
    Abstract:

    In this study, the adsorption of Pb(II) on β-MnO2 as a function of various environmental conditions such as contact time, pH, ionic strength, humic acid (HA)/fulvic acid (FA), and temperature was investigated using batch techniques. The results indicated that the adsorption of Pb(II) on β-MnO2 was obviously dependent on pH but independent of ionic strength. The presence of HA/FA enhanced the adsorption of Pb(II) on β-MnO2 at low pH, whereas reduced Pb(II) adsorption on β-MnO2 at high pH. The kinetic adsorption of Pb(II) on β-MnO2 can be well fitted by the pseudo-second-order rate equation. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were also calculated from the temperature dependent adsorption isotherms, and the results suggested that the adsorption of Pb(II) on β-MnO2 was a spontaneous and Endothermic Process. The adsorption of Pb(II) on β-MnO2 was attributed to surface complexation rather than ion exchange.