Synthesis of kaolinite/iron oxide magnetic composites and their use in the removal of Cd(II) from aqueous solutions

2013 ◽  
Vol 67 (7) ◽  
pp. 1642-1649 ◽  
Author(s):  
Pengfei Zong ◽  
Shoufang Wang ◽  
Chaohui He
Keyword(s):  
Iron Oxide ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sorption Capacity ◽  
Sorption Isotherms ◽  
Entropy Change ◽  
Solution Chemistry ◽  
Standard Entropy ◽  
Iron Oxide Particles ◽  
Magnetic Composites

Kaolinite/iron oxide magnetic composites (kaolinite/MCs) were used as adsorbent for the removal of Cd(II) from aqueous solutions. The influences of pH, ionic strength, solid/liquid ratio and temperature on Cd(II) sorption on kaolinite/MCs were evaluated. The results showed that the removal of Cd(II) on kaolinite/MCs was strongly dependent on pH and ionic strength. An optimal kaolinite/MCs concentration mass per volume for removal of Cd(II) from aqueous solutions was 1.4 g L–1. The Langmuir and Freundlich models were used to simulate sorption isotherms of Cd(II) at three different temperatures of 293, 313 and 333 K. The sorption of Cd(II) on kaolinite/MCs increased with increasing temperature, and thermodynamic parameters (standard entropy change, enthalpy change and Gibbs free energy change) illustrated that this sorption process was spontaneous and endothermic. The sorption behaviors of Cd(II) were mainly dependent on surface properties of kaolinite/MCs and solution chemistry conditions. The sorption capacity of Cd(II) on kaolinite/MCs was lower than that on kaolinite, because iron oxide particles decreased surface charge of kaolinite leading to less sorption capacity. Due to high magnetism, kaolinite/MCs could be easily separated with an external magnetic field. Kaolinite/MCs could therefore be used as potential adsorbent for preconcentration and immobilization of Cd(II) ions from large volumes of aqueous solutions.

scholarly journals Potential of Iron Pillared Clay as Active Nanocatalyst for Rapid Decolorization of Methylene Blue

2019 ◽  
Vol 7 (2) ◽  
pp. 46-53
Author(s):  
Lal hmunsiama ◽  
◽  
Seung-Mok Lee ◽  
Keyword(s):  
Methylene Blue ◽  
Iron Oxide ◽  
Aqueous Solutions ◽  
Low Cost ◽  
Analytical Data ◽  
Bentonite Clay ◽  
Pillared Clay ◽  
Oh Radicals ◽  
Heterogeneous Structure ◽  
Iron Oxide Particles

In this study, the iron-pillared clay nanocatalyst (ICN) was employed as a nanocatalyst for decolorization of methylene blue (MB) in aqueous solutions without hydrogen peroxide. The changes in clay structure after the incorporation of iron-oxide particles was studied with the help of XRD analytical data. The SEM micrographs showed higher heterogeneous structure of ICN compared to pristine clay and the specific surface area of ICN (82.54 m2/g) is considerably higher than the unmodified clay (63.41 m2/g). Further, the EDX analytical data indicate the successful incorporation of iron-oxide into bentonite clay. Batch experiments showed that ICN could degrade MB within pH 3.0 to 11.0 and it is efficient even at higher concentrations. The degradation is very fast and more than 90% is removed within 30 mins. A small amount of ICN is effective for degradation of MB and the reusability test showed that ICN can be reuse for several times for the degradation of MB in aqueous solutions. The effect of scavengers studies indicate that the ·OH radicals generated from the ICN are responsible in the degradation of MB. This study indicates that ICN must be low cost and environmentally friendly active nanocatalyst for degradation of MB present in aquatic environment.

Removal of Pb(II) and Cu(II) from aqueous solution using multiwalled carbon nanotubes/iron oxide magnetic composites

2011 ◽  
Vol 63 (5) ◽  
pp. 917-923 ◽  
Author(s):  
Jun Hu ◽  
Donglin Zhao ◽  
Xiangke Wang
Keyword(s):  
Carbon Nanotubes ◽  
Iron Oxide ◽  
Multiwalled Carbon Nanotubes ◽  
Sorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Precipitation Method ◽  
Multiwalled Carbon ◽  
Magnetic Composites ◽  
X Ray

Multiwalled carbon nanotubes (MWCNTs)/iron oxide magnetic composites (named as MCs) were prepared by co-precipitation method, and were characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) in detail. The prepared MCs were employed as an adsorbent for the removal of Pb(II) and Cu(II) ions from wastewater in heavy metal ion pollution cleanup. The results demonstrated that the sorption of Pb(II) and Cu(II) ions was strongly dependent on pH and temperature. The experimental data were well described by Langmuir model, and the monolayer sorption capacity of MCs was found to vary from 10.02 to 31.25 mg/g for Pb(II) and from 3.11 to 8.92 mg/g for Cu(II) at temperature increasing from 293.15 to 353.15 K at pH 5.50. The sorption capacity of Pb(II) on MCs was higher than that of Cu(II), which was attributed to their ionic radius, hydration energies and hydrolysis of their hydroxides. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) were calculated from temperature dependent sorption isotherms, and the results indicated that the sorption of Pb(II) and Cu(II) ions on MCs were spontaneous and endothermic processes.

scholarly journals A method for investigating the effect of temperature on the 695 nm band of insoluble cytochrome c

1975 ◽  
Vol 149 (1) ◽  
pp. 169-177 ◽  
Author(s):  
T A Moore ◽  
C Greenwood
Keyword(s):  
Ionic Strength ◽  
Cytochrome C ◽  
Computer Analysis ◽  
Standard Enthalpy ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Effect Of Temperature ◽  
Standard Entropy ◽  
Ferricytochrome C ◽  
Standard Enthalpy Change

A method is described for computer analysis of simple spectrophotometric changes in particulate systems, and this has been applied to the bleaching of the 695 nm band of insoluble ferricytochrome c by temperature. The results show that insolubilization has no effect on the standard enthalpy change but lowers the value for the standard entropy change. This effect appears to be independent of the concentration of the gel matrix to which the cytochrome c is bound, but dependent on the ionic strength of the surrounding solution.

Sorption of Am(III) on attapulgite/iron oxide magnetic composites: effect of pH, ionic strength and humic acid

2012 ◽  
Vol 100 (10) ◽  
pp. 753-758 ◽  
Author(s):  
T. Yu ◽  
Qiao Hui Fan ◽  
W. S. Wu ◽  
S. P. Liu ◽  
D. Q. Pan ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Humic Acid ◽  
Ionic Strength ◽  
Magnetic Composites ◽  
Effect Of Ph

scholarly journals Sorption capacity of phosphate in mineral soils: I Estimation of sorption capacity by means of sorption isotherms

1990 ◽  
Vol 62 (1) ◽  
pp. 1-8
Author(s):  
Raina Niskanen
Keyword(s):  
Ionic Strength ◽  
Sorption Capacity ◽  
Sorption Isotherms ◽  
Clay Content ◽  
Langmuir Equation ◽  
Soil Samples ◽  
Organic Carbon Content ◽  
Sorption Data ◽  
Mineral Soils ◽  
Extractable Al

The sorption capacity of phosphate in seven soil samples (clay content 1—70 %, organic carbon content 0.8—10.7 %, soil pH 4.2—5.3, oxalate-extractable Al 11—222 and Fe 11—202 mmol/kg soil) was studied by means of sorption isotherms. The soils were equilibrated, for two to seven days at +5 and +20°C, with solutions containing phosphate 0—10 mmol/l (0—200 mmol/kg soil) at a constant ionic strength of 0.01 . Prolongation of the reaction time increased the sorption of phosphate only partially. The rise in temperature, from +5 to +20°C, increased the sorption from higher phosphate concentrations. At +20°C, the sorption curves of three soils showed a sorption maximum of 4, 19 and 34 mmol/kg soil. The sorption data of six soils was in accordance with the Langmuir equation; the sorption maximum ranged from 15 to 119 mmol/kg soil, and were of the same magnitude as the maximums determined experimentally.

scholarly journals BENTONITE/IRON OXIDE MAGNETIC COMPOSITES: CHARACTERIZATION AND APPLICATION AS Pb(II) ADSORBENTS

2017 ◽  
Vol 1 (16) ◽  
Author(s):  
Zuzana Danková ◽  
Erika Fedorová ◽  
Alexandra Bekényiová
Keyword(s):  
Iron Oxide ◽  
Metal Ion ◽  
Nitrogen Adsorption ◽  
Ion Concentration ◽  
Natural Clay ◽  
Iron Oxide Particles ◽  
Magnetic Composites ◽  
Ion Concentrations ◽  
Oxide Particles ◽  
Adsorption Rates

The natural clay bentonite (B) as adsorbent of lead cations was studied. To enhance its adsorptioncapacity, the coating by iron oxide particles, in two selected weight ratios: 2:1 (BM1) and 4:1(BM2),was used. The changes of the textural and surface parameters after the modification were studied by thelow temperature nitrogen adsorption, XRD and SEM method, Mössbauer spectroscopy. The Pb(II)adsorption experiments were studied under the different conditions, such as pH of the model solutions,contact time and initial metal ion concentration. Higher adsorption rates of BM1 and BM2 sampleswere observed for lower initial metal ion concentrations.

Experimental Investigation of Thermodynamics, Kinetics, and Equilibrium of Nickel Ion Removal from Wastewater Using Zinc Oxide Nanoparticles as the Adsorbent

2020 ◽  
Vol 38 (7A) ◽  
pp. 1047-1061
Author(s):  
Shurooq T. Remedhan
Keyword(s):  
Zinc Oxide ◽  
Aqueous Solutions ◽  
Zno Nanoparticles ◽  
Metal Ion ◽  
Entropy Change ◽  
Ion Concentration ◽  
Standard Entropy ◽  
Nickel Ion ◽  
X Ray ◽  
Operation Conditions

In the present study commercial zinc oxide (ZnO) nanoparticles in the size of 30 nm were utilized as an adsorbent for the removal of Ni (II) ion from synthetic waste aqueous solution. Adsorption capacity of ZnO for removing Ni (II) ions from aqueous solutions was measured at different pH, adsorbent dose, contact time, temperature and metal ion concentration. Moreover,  adsorption isotherms, kinetics and thermodynamics were studied to understand  the  nature  and  mechanism  of  adsorption. ZnO nanoparticles were characterized by X-Ray diffract analysis(XRD),Fourier Transform Infrared Spectroscopy(FT-IR), scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy(EDS) and Brunauer-Emmett-Teller (BET). The maximum amount of Ni (II) removal were found to be (98.71%) from its aqueous solutions by ZnO nanoparticles which was achieved at the evaluated optimum conditions. The experimental kinetic data were examined using the pseudo-second-order rate model with a high regression coefficient. The adsorption isotherm was well described to the equilibrium data by Langmuir isotherm model (R2=0.990). In addition, the calculated thermodynamic parameters, the standard Gibbs free energy ΔGo, the change in standard enthalpy ∆Ho and the standard entropy change ∆So showed that the adsorption of Ni (II) onto ZnO nanoparticles was feasible, endothermic and spontaneous respectively. The experimental results suggest that ZnO nanoparticles can be used as a potential adsorbent for the efficient removal of heavy metals from aqueous solutions than any other adsorbent because an economical and low- consumption energy due to its ambient operation conditions.

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