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Li-qun Zhang - One of the best experts on this subject based on the ideXlab platform.

  • preparation and properties of natural rubber Rectorite nanocomposites
    European Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Abstract Natural rubber (NR)/Rectorite nanocomposite was prepared by co-coagulating NR latex and Rectorite aqueous suspension. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the nanocomposite. The results showed that the nanocomposite exhibited a higher glass transition temperature, lower tan δ peak value and slightly broader glass transition region compared with pure NR. The gas barrier properties of the NR/Rectorite nanocomposites were remarkably improved by the introduction of nanoscale Rectorite because of the increased tortuosity of the diffusive path for a penetrant molecule. The nanocomposites have a unique stress–strain behavior due to the reinforcement and the hindrance of Rectorite layers to the tensile crystallization of NR.

  • Preparation, structure, and properties of a novel Rectorite/styrene-butadiene copolymer nanocomposite
    Journal of Applied Polymer Science, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and Rectorite/water suspension. Transmission electron microscopy showed that the layers of Rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X-ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005

  • preparation structure and properties of a novel Rectorite styrene butadiene copolymer nanocomposite
    Journal of Applied Polymer Science, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and Rectorite/water suspension. Transmission electron microscopy showed that the layers of Rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X-ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005

  • Preparation, Structure, and Properties of a Novel Rectorite/Nitrile Butadiene Rubber (NBR) Nanocomposites
    Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Wei Zhao, Chang-xiu Wang, Li-qun Zhang
    Abstract:

    Rectorite/nitrile butadiene rubber (NBR) nanocomposite was firstly prepared by co-coagulating NBR latex and Rectorite water suspension. The microstructure of the resulted nanocomposite was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that the Rectorite layers were dispersed in the NBR matrix in form of single layers and nano-meter stacking layers. Moreover, the nano-sized stacking layers were not intercalated. Compared with silica or carbon black, the incorporation of Rectorite in NBR leads to stronger filler network in the compound and further results in higher storage modulus of the vulcanizate. The mechanical properties and the gas barrier property of Rectorite/NBR vulcanizate were remarkably improved by introduction of nano-dispersed Rectorite.

  • Preparation and properties of natural rubber/Rectorite nanocomposites
    European Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Abstract Natural rubber (NR)/Rectorite nanocomposite was prepared by co-coagulating NR latex and Rectorite aqueous suspension. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the nanocomposite. The results showed that the nanocomposite exhibited a higher glass transition temperature, lower tan δ peak value and slightly broader glass transition region compared with pure NR. The gas barrier properties of the NR/Rectorite nanocomposites were remarkably improved by the introduction of nanoscale Rectorite because of the increased tortuosity of the diffusive path for a penetrant molecule. The nanocomposites have a unique stress–strain behavior due to the reinforcement and the hindrance of Rectorite layers to the tensile crystallization of NR.

Gaoke Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Adsorption of Methylene Blue from Aqueous Solution onto Hydrochloric Acid-modified Rectorite
    Journal of Wuhan University of Technology-Mater. Sci. Ed., 2011
    Co-Authors: Gaoke Zhang, Guanfeng Liu, Yadan Guo
    Abstract:

    H+-Rectorite clay, which was prepared by modifying the raw Rectorite with 10% hydrochloric acid at 60 °C for 24 h, was used as an absorbent for removal of methyl blue (MB) from aqueous solutions. The morphology and the structure and crystallinity of the pristine Rectorite and the H+-Rectorite were characterized by scanning electron microscopy (SEM) technique and X-ray diffraction (XRD) technique, respectively. The results showed that the H+-Rectorite exhibited high adsorption ability than the raw Rectorite, and it was found that the removal percentage of MB increased with increasing in adsorbents dose, whereas the adsorption amount q e (mg/g) decreased. The equilibrium was attained within 30 min in adsorption process, and the maximum adsorption capacity of H+-Rectorite for methylene blue reached as high as 37 mg/g. Besides, the effect of temperature on the adsorption of MB with H+-Rectorite was investigated and the equilibrium data were well fitted to Freundlich equations. The H+-Rectorite absorbent saturated with MB can be regenerated by calcinating at 400 °C for 2 h and the regenerated absorbent still showed higher percentage removal of MB.

  • facile synthesis and photocatalytic property of bicrystalline tio2 Rectorite composites
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
    Co-Authors: Yalei Zhang, Gaoke Zhang, Lijuan Deng, Huihui Gan
    Abstract:

    Abstract The TiO 2 /Rectorite composites with a bicrystalline (anatase and rutile) framework were synthesized by a facile sol–gel method using titanium tetraisopropoxide as a TiO 2 precursor at different temperatures. The as-obtained composites were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectrum, and Brunauer–Emmett–Teller (BET). XRD and HRTEM analyses confirm that the layered structure of Rectorite in the TiO 2 /Rectorite composites was destroyed to some extent. The TiO 2 /Rectorite composites prepared at low temperature (80 °C) without calcination exhibited strong adsorbility for acid red G (ARG), and showed a high photocatalytic activity for the decomposition of ARG and the persistent organic pollutant 4-nitrophenol (4-NP) under UV irradiation. The excellent photocatalytic activity of the as-obtained composites can be attributed to the synergetic effect of the anatase–rutile mixed phase and bimodal pore structure in the composites. A possible mechanism of the photocatalysis over the TiO 2 /Rectorite composites was proposed.

  • Facile synthesis and photocatalytic property of bicrystalline TiO2/Rectorite composites
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
    Co-Authors: Yalei Zhang, Gaoke Zhang, Lijuan Deng, Huihui Gan
    Abstract:

    Abstract The TiO 2 /Rectorite composites with a bicrystalline (anatase and rutile) framework were synthesized by a facile sol–gel method using titanium tetraisopropoxide as a TiO 2 precursor at different temperatures. The as-obtained composites were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectrum, and Brunauer–Emmett–Teller (BET). XRD and HRTEM analyses confirm that the layered structure of Rectorite in the TiO 2 /Rectorite composites was destroyed to some extent. The TiO 2 /Rectorite composites prepared at low temperature (80 °C) without calcination exhibited strong adsorbility for acid red G (ARG), and showed a high photocatalytic activity for the decomposition of ARG and the persistent organic pollutant 4-nitrophenol (4-NP) under UV irradiation. The excellent photocatalytic activity of the as-obtained composites can be attributed to the synergetic effect of the anatase–rutile mixed phase and bimodal pore structure in the composites. A possible mechanism of the photocatalysis over the TiO 2 /Rectorite composites was proposed.

  • Synthesis and Characterization of Ibuprofen-Rectorite Composites by Solution Intercalation Method
    Journal of Wuhan University of Technology-Mater. Sci. Ed., 2009
    Co-Authors: Huiyan Wang, Gaoke Zhang, Huihu Gan, Yuanyuan Gao
    Abstract:

    The ibuprofen-Rectorite composites were prepared by the solution intercalation method using ibuprofen and Rectorite as raw materials, and were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared analysis and scanning electron microscopy (SEM). The experimental results show that the ibuprofen is intercalated into the interlayer spaces of Rectorite. The values of the (001) peaks of the ibuprofen-Rectorite composite are larger than that of Na-Rectorite and reach the largest when the reaction time and ibuprofen amount is 2 h and 0.36 g, respectively. The layered structure of Na-Rectorite is destroyed to some extent with the intercalation of ibuprofen into the interlayer space in the structure of Na-Rectorite. A part of ibuprofen in the ibuprofen Na-Rectorite covers on the surface of Na-Rectorite besides some ibuprofen enters into the interlayer space.

  • Zinc adsorption on Na-Rectorite and effect of static magnetic field on the adsorption
    Applied Clay Science, 2005
    Co-Authors: Gaoke Zhang, Ying Liu, Yi Xie, Xia Yang, Shixi Ouyang, Hanxing Liu, Huiyan Wang
    Abstract:

    Rectorite is a kind of rare clay minerals. In this work, the sorption of Zn2+ on Na-Rectorite and the effects of static magnetic field on the sorption have been studied. The result from this study indicated that: (1) apparent equilibrium for the sorption of zinc onto Na-Rectorite is attained within the first hour; (2) the maximum of the increment of Zn2+ adsorbed by Na-Rectorite is obtained between pH 4 and pH 6; (3) magnetic treatment enhances the zeta potential of Na-Rectorite dispersions in the absence of Zn2+ and reduces that of the dispersions in the presence of Zn2+; (4) magnetic treatment promotes the sorption of Zn2+ onto Na-Rectorite, especially at the low Zn2+ concentration; (5) the effects of static magnetic field decrease the pH of Na-Rectorite dispersions whether containing zinc or not. The mechanisms of static magnetic field on the sorption of Zn2+ on Na-Rectorite were discussed.

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

  • Eu(III) uptake on Rectorite in the presence of humic acid: A macroscopic and spectroscopic study
    Journal of colloid and interface science, 2012
    Co-Authors: Changlun Chen, Xin Yang, Juan Wei, Xiaoli Tan, Xiangke Wang
    Abstract:

    Abstract This work contributed to the comprehension of humic acid (HA) effect on Eu(III) uptake to Na-Rectorite by batch sorption experiments, model fitting, scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure (EXAFS) spectroscopy. At low pH, the presence of HA enhanced Eu(III) sorption on Na-Rectorite, while reduced Eu(III) sorption at high pH. The experimental data of Eu(III) sorption in the absence and presence of HA were simulated by the diffuse-layer model well with the aid of FITEQL 3.2 software. The basal spacing of Rectorite became large after Eu(III) and HA sorption on Na-Rectorite. Some of Eu(III) ions and HA might be intercalated into the interlayer space of Na-Rectorite. EXAFS analysis showed that the R Eu O (the bond distance of Eu and O in the first shell of Eu) and N values (coordination number) of Eu(III)–HA-Rectorite system were smaller than those of Eu(III)-Rectorite system.

  • adsorption of sr ii and eu iii on na Rectorite effect of ph ionic strength concentration and modelling
    Radiochimica Acta, 2010
    Co-Authors: Changlun Chen, Guodong Sheng, Yixue Chen, Xiangke Wang
    Abstract:

    The surface charge characteristics of Na-Rectorite (NaAl 4 [Si,bAl] 8 O 20 (OH) 4 ·nH 2 O) were studied by potentiometric acid-base titrations. Sr(II) and Eu(III) adsorptions on Na-Rectorite as a function of pH, ionic strength, and Sr(II)/Eu(III) concentrations were carried out to investigate the surface interactions between Sr(II)/Eu(III) with Na-Rectorite. The results indicated that the adsorptions of Sr(II) and Eu(III) on Na-Rectorite increased with increasing pH and decreased with increasing ionic strength and initial Sr(II)/Eu(III) concentrations, and that the affinity of Na-Rectorite for Eu(III) was much higher than for Sr(II). The experimental data of Sr(II)/Eu(III) adsorption were simulated by the diffuse-layer model (DLM) well with the aid of FTTEQL 3.2. Simultaneous adsorptions of Sr(II) and Eu(III) on Na-Rectorite were also modeled using the DLM. The adsorption mechanisms of Sr(II) and Eu(III) on Na-Rectorite may be dominated by ion exchange interaction at low pH or moderate pH, and by surface complexation interaction at high pH.

  • adsorption of th iv onto al pillared Rectorite effect of ph ionic strength temperature soil humic acid and fulvic acid
    Applied Clay Science, 2008
    Co-Authors: Changlun Chen, P Chang, Tong Wang, Xiangke Wang
    Abstract:

    Abstract The adsorption of Th(IV) onto Al-pillared Rectorite as a function of Rectorite concentration, Th concentration, pH, ionic strength, temperature, soil humic acid (HA) and fulvic acid (FA) was studied by using batch technique under ambient condition. The results indicated that the adsorption of Th(IV) onto Al-pillared Rectorite strongly depended on pH and ionic strength, and the adsorption of Th(IV) increased with increasing Al-pillared Rectorite concentration. The presence of HA/FA enhanced Th(IV) adsorption at low pH and reduced Th(IV) adsorption at high pH. The adsorption of Th(IV) decreased with increasing temperature, indicating that the adsorption process of Th(IV) onto Al-pillared Rectorite was exothermic. The experimental data of Th(IV) adsorption were analyzed with the Freundlich and Langmuir models, showing that the Freundlich model fitted the adsorption data better than the Langmuir model. The adsorption of Th(IV) on Al-pillared Rectorite may be dominated by surface complexation and cation exchange also contributed partly to Th(IV) adsorption.

  • Sorption of Ni2+ on Na-Rectorite studied by batch and spectroscopy methods
    Applied Geochemistry, 2008
    Co-Authors: Xiaoli Tan, Changlun Chen, Xiangke Wang
    Abstract:

    Sorption of Ni2+ on Na-Rectorite as a function of contact time, temperature, pH and fulvic acid (FA)/humic acid (HA) was studied under ambient conditions. A pseudo-second-order rate equation was used to simulate the kinetic sorption. The removal of Ni2+ increased with increasing pH. The presence of FA/HA enhanced the sorption of Ni2+ at low pH values, whereas no drastic effect of FA/HA on Ni2+ uptake to Rectorite was found at high pH values. The diffuse layer model (DLM) fitted the experimental data of Ni2+ sorption in the absence and presence of FA/HA very well with the aid of FITEQL 3.2. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were used to simulate the sorption isotherms of Ni2+ at different temperatures. The thermodynamic data (ΔH0, ΔS0, ΔG0) were calculated from the temperature dependent sorption isotherms and the results suggested that the sorption process of Ni2+ on Rectorite was spontaneous and endothermic. The sorption and species of Ni2+ on Rectorite in the presence and absence of FA/HA was also investigated and characterized by XPS. The spectroscopic analysis indicated no drastic structural changes of Na-Rectorite and the sorption of Ni2+ mainly occurred on the surface and at the edge position of Na-Rectorite.

  • sorption of th iv on na Rectorite effect of ha ionic strength foreign ions and temperature
    Applied Geochemistry, 2007
    Co-Authors: Changlun Chen, Xiaoli Tan, Xiangke Wang
    Abstract:

    The sorption of Th(IV) on Na-Rectorite as a function of pH, ionic strength, temperature, soil humic acid (HA) and foreign ions was studied by using a batch technique under ambient conditions. The results indicated that the sorption of Th(IV) on Na-Rectorite is strongly depended on pH, ionic strength and temperature. The presence of HA enhanced Th(IV) sorption at low pH and had no obvious effect on Th(IV) sorption at high pH. The sorption of Th(IV) decreased with increasing temperature, indicating that the sorption process of Th(IV) on Rectorite was exothermic. Sodium-Rectorite and HA were characterized by acid–base titration to obtain the pKa, and the constant capacitance model (CCM) modeled the sorption data very well with the aid of FITEQL 3.2. HA/Th(IV) addition sequences affected Th(IV) sorption in the ternary systems. The sorption of Th(IV) on Na-Rectorite may be dominated by surface complexation, while cation exchange also contributes partly to the sorption.

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

  • preparation and properties of natural rubber Rectorite nanocomposites
    European Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Abstract Natural rubber (NR)/Rectorite nanocomposite was prepared by co-coagulating NR latex and Rectorite aqueous suspension. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the nanocomposite. The results showed that the nanocomposite exhibited a higher glass transition temperature, lower tan δ peak value and slightly broader glass transition region compared with pure NR. The gas barrier properties of the NR/Rectorite nanocomposites were remarkably improved by the introduction of nanoscale Rectorite because of the increased tortuosity of the diffusive path for a penetrant molecule. The nanocomposites have a unique stress–strain behavior due to the reinforcement and the hindrance of Rectorite layers to the tensile crystallization of NR.

  • Preparation, structure, and properties of a novel Rectorite/styrene-butadiene copolymer nanocomposite
    Journal of Applied Polymer Science, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and Rectorite/water suspension. Transmission electron microscopy showed that the layers of Rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X-ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005

  • preparation structure and properties of a novel Rectorite styrene butadiene copolymer nanocomposite
    Journal of Applied Polymer Science, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and Rectorite/water suspension. Transmission electron microscopy showed that the layers of Rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X-ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005

  • Preparation, Structure, and Properties of a Novel Rectorite/Nitrile Butadiene Rubber (NBR) Nanocomposites
    Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Wei Zhao, Chang-xiu Wang, Li-qun Zhang
    Abstract:

    Rectorite/nitrile butadiene rubber (NBR) nanocomposite was firstly prepared by co-coagulating NBR latex and Rectorite water suspension. The microstructure of the resulted nanocomposite was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that the Rectorite layers were dispersed in the NBR matrix in form of single layers and nano-meter stacking layers. Moreover, the nano-sized stacking layers were not intercalated. Compared with silica or carbon black, the incorporation of Rectorite in NBR leads to stronger filler network in the compound and further results in higher storage modulus of the vulcanizate. The mechanical properties and the gas barrier property of Rectorite/NBR vulcanizate were remarkably improved by introduction of nano-dispersed Rectorite.

  • Preparation and properties of natural rubber/Rectorite nanocomposites
    European Polymer Journal, 2005
    Co-Authors: Yi-qing Wang, Hui-feng Zhang, Jun Yang, Li-qun Zhang
    Abstract:

    Abstract Natural rubber (NR)/Rectorite nanocomposite was prepared by co-coagulating NR latex and Rectorite aqueous suspension. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the nanocomposite. The results showed that the nanocomposite exhibited a higher glass transition temperature, lower tan δ peak value and slightly broader glass transition region compared with pure NR. The gas barrier properties of the NR/Rectorite nanocomposites were remarkably improved by the introduction of nanoscale Rectorite because of the increased tortuosity of the diffusive path for a penetrant molecule. The nanocomposites have a unique stress–strain behavior due to the reinforcement and the hindrance of Rectorite layers to the tensile crystallization of NR.

Changlun Chen - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of the influence of environmental conditions on the removal of pb ii from wastewater by ca Rectorite
    Separation Science and Technology, 2015
    Co-Authors: Huiyang Mei, Xiaoli Tan, Shaowei Wang, Changlun Chen
    Abstract:

    The removal of Pb(II) from wastewater by Ca-Rectorite was investigated as various environmental factors containing contact time, pH, ionic strength, solid content, coexisting ions, humic acid (HA), and temperature. The kinetic sorption of Pb(II) on Ca-Rectorite was well described by the pseudo second-order model. The sorption process was strongly dependent on pH and ionic strength. The results indicated that the presence of HA and coexisting ions influenced the sorption of Pb(II) on Ca-Rectorite obviously. Besides, the Langmuir and Freundlich models were employed to simulate the sorption isotherms. The thermodynamic parameters indicated that the sorption process was spontaneous and endothermic. It is possible to conclude that Ca-Rectorite has a good potential for disposal of lead-contaminated wastewater.

  • Effect of environmental conditions on the adsorption behavior of Sr(II) by Na-Rectorite
    Applied Clay Science, 2014
    Co-Authors: Ying Zhao, Changlun Chen, Zhenyi Shao, Hongli Chen
    Abstract:

    Abstract The adsorption behavior of Sr(II) by Na-Rectorite was investigated as a function of various environmental parameters such as pH, ionic strength, humic acid (HA) and temperature under ambient conditions. The results indicated that the adsorption of Sr(II) on Na-Rectorite was strongly dependent on pH and ionic strength. The presence of HA enhanced the adsorption of Sr(II) on Na-Rectorite at low pH, whereas suppressed Sr(II) adsorption on Na–Rectorite at high pH. The Langmuir model simulated the adsorption isotherms of Sr(II) better than the Freundlich model at three different temperatures of 293, 313 and 333 K. The thermodynamic parameters (Δ H 0 , Δ S 0 and Δ G 0 ) calculated from the temperature dependent adsorption isotherms indicated that the adsorption process of Sr(II) on Na–Rectorite was spontaneous and endothermic. The adsorption of Sr(II) was dominated by outer-sphere surface complexation and ion exchange at low pH, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH. The results indicate that Na-Rectorite may be a promising candidate for the treatment of radionuclides from large volume solution.

  • Eu(III) uptake on Rectorite in the presence of humic acid: A macroscopic and spectroscopic study
    Journal of colloid and interface science, 2012
    Co-Authors: Changlun Chen, Xin Yang, Juan Wei, Xiaoli Tan, Xiangke Wang
    Abstract:

    Abstract This work contributed to the comprehension of humic acid (HA) effect on Eu(III) uptake to Na-Rectorite by batch sorption experiments, model fitting, scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure (EXAFS) spectroscopy. At low pH, the presence of HA enhanced Eu(III) sorption on Na-Rectorite, while reduced Eu(III) sorption at high pH. The experimental data of Eu(III) sorption in the absence and presence of HA were simulated by the diffuse-layer model well with the aid of FITEQL 3.2 software. The basal spacing of Rectorite became large after Eu(III) and HA sorption on Na-Rectorite. Some of Eu(III) ions and HA might be intercalated into the interlayer space of Na-Rectorite. EXAFS analysis showed that the R Eu O (the bond distance of Eu and O in the first shell of Eu) and N values (coordination number) of Eu(III)–HA-Rectorite system were smaller than those of Eu(III)-Rectorite system.

  • adsorption of sr ii and eu iii on na Rectorite effect of ph ionic strength concentration and modelling
    Radiochimica Acta, 2010
    Co-Authors: Changlun Chen, Guodong Sheng, Yixue Chen, Xiangke Wang
    Abstract:

    The surface charge characteristics of Na-Rectorite (NaAl 4 [Si,bAl] 8 O 20 (OH) 4 ·nH 2 O) were studied by potentiometric acid-base titrations. Sr(II) and Eu(III) adsorptions on Na-Rectorite as a function of pH, ionic strength, and Sr(II)/Eu(III) concentrations were carried out to investigate the surface interactions between Sr(II)/Eu(III) with Na-Rectorite. The results indicated that the adsorptions of Sr(II) and Eu(III) on Na-Rectorite increased with increasing pH and decreased with increasing ionic strength and initial Sr(II)/Eu(III) concentrations, and that the affinity of Na-Rectorite for Eu(III) was much higher than for Sr(II). The experimental data of Sr(II)/Eu(III) adsorption were simulated by the diffuse-layer model (DLM) well with the aid of FTTEQL 3.2. Simultaneous adsorptions of Sr(II) and Eu(III) on Na-Rectorite were also modeled using the DLM. The adsorption mechanisms of Sr(II) and Eu(III) on Na-Rectorite may be dominated by ion exchange interaction at low pH or moderate pH, and by surface complexation interaction at high pH.

  • adsorption of th iv onto al pillared Rectorite effect of ph ionic strength temperature soil humic acid and fulvic acid
    Applied Clay Science, 2008
    Co-Authors: Changlun Chen, P Chang, Tong Wang, Xiangke Wang
    Abstract:

    Abstract The adsorption of Th(IV) onto Al-pillared Rectorite as a function of Rectorite concentration, Th concentration, pH, ionic strength, temperature, soil humic acid (HA) and fulvic acid (FA) was studied by using batch technique under ambient condition. The results indicated that the adsorption of Th(IV) onto Al-pillared Rectorite strongly depended on pH and ionic strength, and the adsorption of Th(IV) increased with increasing Al-pillared Rectorite concentration. The presence of HA/FA enhanced Th(IV) adsorption at low pH and reduced Th(IV) adsorption at high pH. The adsorption of Th(IV) decreased with increasing temperature, indicating that the adsorption process of Th(IV) onto Al-pillared Rectorite was exothermic. The experimental data of Th(IV) adsorption were analyzed with the Freundlich and Langmuir models, showing that the Freundlich model fitted the adsorption data better than the Langmuir model. The adsorption of Th(IV) on Al-pillared Rectorite may be dominated by surface complexation and cation exchange also contributed partly to Th(IV) adsorption.