Synthesis and Application of C-Phenylcalix[4]resorcinarene in Adsorption of Cr(III) and Pb(II), for more information visit our website http://jacsonline.org/
A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synthetic humic acids (SHA) were examined by fluorescence spectroscopy, which indicated similarity of SHA and HA spectra. The AFM images of SHA and its complexes revealed variable morphologies, such as small spheres, aggregates and a sponge-like structure. The SHA complexes displayed morphologies similar to those of natural HA. The presence of copper, iron and manganese ions led to the formation of aggregate-type structures in an apparent arrangement of smaller SHA particles.
This PDF presentation describes briefly my research experiences in synthetic organic. The time period of these research projects range from 1999 to 10/2005. Projects of later positions were also included but not all. Time period, place of work and position were mentioned at the beginning of each project. To noted that all the experimental synthesis, separation/purification, characterization and spectral interpretation were performed independently by me.
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
In this paper, a novel copper oxide coated kaolinite was prepared as an adsorbent of Hg(II) ions from aqueous media. The materials used for this study were synthesized, characterised and the product tested for mercury ion removal using standard laboratory procedures. Reactivity and removal kinetic models derived from Freundlich isotherm were used to investigate contact time and pH effects on the coefficient of protonation and rate of mass transfer of Hg(II) ions to the reactive sites, Proton coefficient of 0.89 indicated a decrease in proton consumption function when compared with uncoated kaolinite. At the 12th h reaction time, a maximum adsorption capacity of 85% was achieved. Mass transfer rates of 0.9359h-1 and 0.0748h-1 for the first and second reaction phases indicated a reduction when compared with uncoated kaolinite. These changes may be ascribed to masking of reaction sites and exposed surface area of the Cu-Oxide coated kaolinite.
Visible light assisted hydrogen generation from complete decomposition of hyd...Pawan Kumar
Hydrogen is considered to be an ideal energy carrier, which produces only water when combined with
oxygen and thus has no detrimental effect on the environment. While the catalytic decomposition of
hydrous hydrazine for the production of hydrogen is well explored, little is known about its photocatalytic
decomposition. The present paper describes a highly efficient photochemical methodology for the production
of hydrogen through the decomposition of aqueous hydrazine using titanium dioxide nanoparticles
modified with a Rh(I) coordinated catechol phosphane ligand (TiO2–Rh) as a photocatalyst under visible
light irradiation. After 12 h of visible light irradiation, the hydrogen yield was 413 μmol g−1 cat with a hydrogen
evolution rate of 34.4 μmol g−1 cat h−1. Unmodified TiO2 nanoparticles offered a hydrogen yield of
83 μmol g−1 cat and a hydrogen evolution rate of only 6.9 μmol g−1 cat h−1. The developed photocatalyst
was robust under the experimental conditions and could be efficiently reused for five subsequent runs
without any significant change in its activity. The higher stability of the photocatalyst is attributed to the
covalent attachment of the Rh complex, whereas the higher activity is believed to be due to the synergistic
mechanism that resulted in better electron transfer from the Rh complex to the conduction band of TiO2.
Synthesis, Characterization and antimicrobial activity of some novel sulfacet...iosrjce
IOSR Journal of Applied Chemistry (IOSR-JAC) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synthetic humic acids (SHA) were examined by fluorescence spectroscopy, which indicated similarity of SHA and HA spectra. The AFM images of SHA and its complexes revealed variable morphologies, such as small spheres, aggregates and a sponge-like structure. The SHA complexes displayed morphologies similar to those of natural HA. The presence of copper, iron and manganese ions led to the formation of aggregate-type structures in an apparent arrangement of smaller SHA particles.
This PDF presentation describes briefly my research experiences in synthetic organic. The time period of these research projects range from 1999 to 10/2005. Projects of later positions were also included but not all. Time period, place of work and position were mentioned at the beginning of each project. To noted that all the experimental synthesis, separation/purification, characterization and spectral interpretation were performed independently by me.
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
In this paper, a novel copper oxide coated kaolinite was prepared as an adsorbent of Hg(II) ions from aqueous media. The materials used for this study were synthesized, characterised and the product tested for mercury ion removal using standard laboratory procedures. Reactivity and removal kinetic models derived from Freundlich isotherm were used to investigate contact time and pH effects on the coefficient of protonation and rate of mass transfer of Hg(II) ions to the reactive sites, Proton coefficient of 0.89 indicated a decrease in proton consumption function when compared with uncoated kaolinite. At the 12th h reaction time, a maximum adsorption capacity of 85% was achieved. Mass transfer rates of 0.9359h-1 and 0.0748h-1 for the first and second reaction phases indicated a reduction when compared with uncoated kaolinite. These changes may be ascribed to masking of reaction sites and exposed surface area of the Cu-Oxide coated kaolinite.
Visible light assisted hydrogen generation from complete decomposition of hyd...Pawan Kumar
Hydrogen is considered to be an ideal energy carrier, which produces only water when combined with
oxygen and thus has no detrimental effect on the environment. While the catalytic decomposition of
hydrous hydrazine for the production of hydrogen is well explored, little is known about its photocatalytic
decomposition. The present paper describes a highly efficient photochemical methodology for the production
of hydrogen through the decomposition of aqueous hydrazine using titanium dioxide nanoparticles
modified with a Rh(I) coordinated catechol phosphane ligand (TiO2–Rh) as a photocatalyst under visible
light irradiation. After 12 h of visible light irradiation, the hydrogen yield was 413 μmol g−1 cat with a hydrogen
evolution rate of 34.4 μmol g−1 cat h−1. Unmodified TiO2 nanoparticles offered a hydrogen yield of
83 μmol g−1 cat and a hydrogen evolution rate of only 6.9 μmol g−1 cat h−1. The developed photocatalyst
was robust under the experimental conditions and could be efficiently reused for five subsequent runs
without any significant change in its activity. The higher stability of the photocatalyst is attributed to the
covalent attachment of the Rh complex, whereas the higher activity is believed to be due to the synergistic
mechanism that resulted in better electron transfer from the Rh complex to the conduction band of TiO2.
Synthesis, Characterization and antimicrobial activity of some novel sulfacet...iosrjce
IOSR Journal of Applied Chemistry (IOSR-JAC) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
New Schiff base ligand (E)-6-(2-(4-
(dimethylamino)benzylideneamino)-2-phenylacetamido)-3,3-
dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic
acid = (HL) Figure(1) was prepared via condensation of
Ampicillin and 4(dimethylamino)benzaldehyde in methanol
.Polydentate mixed ligand complexes were obtained from 1:1:2
molar ratio reactions with metal ions and HL, 2NA on reaction
with MCl2 .nH2O salt yields complexes corresponding to the
formulas [M(L)(NA)2Cl] ,where M =
Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and NA=nicotinamide.
The 1H-NMR, FT-IR, UV-Vis and elemental analysis
were used for the characterization of the ligand. The complexes
were structurally studied through AAS, FT-IR, UV-Vis,
chloride contents, conductance, and magnetic susceptibility
measurements. All complexes are non-electrolytes in DMSO
solution. Octahedral geometries have been suggested for each
of the complexes. The Schiff base ligands function as
tridentates and the deprotonated enolic form is preferred for
coordination. In order to evaluate the effect of the bactericidal
activity, these synthesized complexes, in comparison to the un
complexed Schiff base has been screened against bacterial
species, Staphy
Visible light assisted reduction of nitrobenzenes using Fe(bpy)3+2/rGOnanocom...Pawan Kumar
Visible-light-induced photocatalytic reduction of aromatic nitrobenzenes to the corresponding anilinesat room temperature using reduced graphene oxide (rGO) immobilized iron(II) bipyridine complex asphotocatalyst is described. The rGO-immobilized iron catalyst exhibited superior catalytic activity thanhomogeneous iron(II) bipyridine complex and much higher than metal free rGO photocatalysts. Theheterogeneous photocatalyst was found to be robust and could easily be recovered and reused for severalruns without any significant loss in photocatalytic activity.
Visible light assisted hydrogen generation from complete decomposition of hyd...Pawan Kumar
Hydrogen is considered to be an ideal energy carrier, which produces only water when combined with
oxygen and thus has no detrimental effect on the environment. While the catalytic decomposition of
hydrous hydrazine for the production of hydrogen is well explored, little is known about its photocatalytic
decomposition. The present paper describes a highly efficient photochemical methodology for the production
of hydrogen through the decomposition of aqueous hydrazine using titanium dioxide nanoparticles
modified with a Rh(I) coordinated catechol phosphane ligand (TiO2–Rh) as a photocatalyst under visible
light irradiation. After 12 h of visible light irradiation, the hydrogen yield was 413 μmol g−1 cat with a hydrogen
evolution rate of 34.4 μmol g−1 cat h−1. Unmodified TiO2 nanoparticles offered a hydrogen yield of
83 μmol g−1 cat and a hydrogen evolution rate of only 6.9 μmol g−1 cat h−1. The developed photocatalyst
was robust under the experimental conditions and could be efficiently reused for five subsequent runs
without any significant change in its activity. The higher stability of the photocatalyst is attributed to the
covalent attachment of the Rh complex, whereas the higher activity is believed to be due to the synergistic
mechanism that resulted in better electron transfer from the Rh complex to the conduction band of TiO2
A Prussian blue/carbon dot nanocomposite as an efficient visible light active...Pawan Kumar
A Prussian blue/carbon dot (PB/CD) nanocomposite was synthesised and used as a visible-light active
photocatalyst for the oxidative cyanation of tertiary amines to α-aminonitriles by using NaCN/acetic acid
as a cyanide source and H2O2 as an oxidant. The developed photocatalyst afforded high yields of products
after 8 h of visible light irradiation at room temperature. The catalyst was recycled and reused several
times without any significant loss in its activity
Crystal Structure, Topological and Hirshfeld Surface Analysis of a Zn(II) Zwi...Awad Albalwi
Abstract: A mononuclear Zn(II) complex of (Zn(H2L) (CH3OH) Cl2
) (1) has been synthesized by using
a nonlinear optically active Zwitterionic Schiff base which is 4-((2-hydroxy-3-methoxybenzylidene)
amino) benzoic acid (H2L). Complex 1 has been structurally analyzed by FTIR and UV spectroscopy,
TGA, Powder-XRD and single crystal X-ray diffraction. X-Ray crystallographic studies revealed Zn(II)
complex crystallizes in a P21/c space group and exists in a distorted trigonal bipyramidal geometry
(τ = 0.68).
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
In this paper, the effect of copper oxide coated kaolinite on mercury (II) removal based on initial metal concentration, particle concentration, and prolonged residence time have been investigated. Experimental methods involved batch mode techniques at ambient temperature. The content was analysed for Hg(II) adsorbed, using standard laboratory procedures. Here, using empirical models derived from Freundlich isotherm, adsorption capacity increased from 300 to 400 mg/kg over the range of initial metal concentration investigated. The complex behavior of existing reactive sites and the generation of new active sites accounted for these changes in adsorption capacity. Increase in particle concentration led to decrease in adsorption. This was over the range of 2, 4, 6, 8 and 10 gL-1 solid concentration. Higher Cp reduced the specific surface area for adsorption. Hg(II) ions removal increased with increase in residence time. The most efficient ratio of Cu-Oxide coated kaolinite was at 0.002kgL-1 at 40mgL-1 mercury concentration. Values of between 600 to 900 mg/kg for Cu-Oxide coated kaolinite was higher when compared with the uncoated kaolinite. As ageing was increased, hydroxylation probably increased thus leading to the formation of new reactive sites.
Presentation given by Enzo Mangano of the University of Edinburgh on "Adsorption Materials and Processes for Carbon Capture from Gas-Fired Power Plants – AMPGas" at the UKCCSRC Gas CCS Meeting, University of Sussex, 25 June 2014
Presentation given by Professor Joe Wood from University of Birmingham on "Studies of Hydrotalcite Clays for CO2 Adsorption " in the Capture Technical Session on Solid Adsorption at the UKCCSRC Biannual Meeting - CCS in the Bigger Picture - held in Cambridge on 2-3 April 2014
New Schiff base ligand (E)-6-(2-(4-
(dimethylamino)benzylideneamino)-2-phenylacetamido)-3,3-
dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic
acid = (HL) Figure(1) was prepared via condensation of
Ampicillin and 4(dimethylamino)benzaldehyde in methanol
.Polydentate mixed ligand complexes were obtained from 1:1:2
molar ratio reactions with metal ions and HL, 2NA on reaction
with MCl2 .nH2O salt yields complexes corresponding to the
formulas [M(L)(NA)2Cl] ,where M =
Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and NA=nicotinamide.
The 1H-NMR, FT-IR, UV-Vis and elemental analysis
were used for the characterization of the ligand. The complexes
were structurally studied through AAS, FT-IR, UV-Vis,
chloride contents, conductance, and magnetic susceptibility
measurements. All complexes are non-electrolytes in DMSO
solution. Octahedral geometries have been suggested for each
of the complexes. The Schiff base ligands function as
tridentates and the deprotonated enolic form is preferred for
coordination. In order to evaluate the effect of the bactericidal
activity, these synthesized complexes, in comparison to the un
complexed Schiff base has been screened against bacterial
species, Staphy
Visible light assisted reduction of nitrobenzenes using Fe(bpy)3+2/rGOnanocom...Pawan Kumar
Visible-light-induced photocatalytic reduction of aromatic nitrobenzenes to the corresponding anilinesat room temperature using reduced graphene oxide (rGO) immobilized iron(II) bipyridine complex asphotocatalyst is described. The rGO-immobilized iron catalyst exhibited superior catalytic activity thanhomogeneous iron(II) bipyridine complex and much higher than metal free rGO photocatalysts. Theheterogeneous photocatalyst was found to be robust and could easily be recovered and reused for severalruns without any significant loss in photocatalytic activity.
Visible light assisted hydrogen generation from complete decomposition of hyd...Pawan Kumar
Hydrogen is considered to be an ideal energy carrier, which produces only water when combined with
oxygen and thus has no detrimental effect on the environment. While the catalytic decomposition of
hydrous hydrazine for the production of hydrogen is well explored, little is known about its photocatalytic
decomposition. The present paper describes a highly efficient photochemical methodology for the production
of hydrogen through the decomposition of aqueous hydrazine using titanium dioxide nanoparticles
modified with a Rh(I) coordinated catechol phosphane ligand (TiO2–Rh) as a photocatalyst under visible
light irradiation. After 12 h of visible light irradiation, the hydrogen yield was 413 μmol g−1 cat with a hydrogen
evolution rate of 34.4 μmol g−1 cat h−1. Unmodified TiO2 nanoparticles offered a hydrogen yield of
83 μmol g−1 cat and a hydrogen evolution rate of only 6.9 μmol g−1 cat h−1. The developed photocatalyst
was robust under the experimental conditions and could be efficiently reused for five subsequent runs
without any significant change in its activity. The higher stability of the photocatalyst is attributed to the
covalent attachment of the Rh complex, whereas the higher activity is believed to be due to the synergistic
mechanism that resulted in better electron transfer from the Rh complex to the conduction band of TiO2
A Prussian blue/carbon dot nanocomposite as an efficient visible light active...Pawan Kumar
A Prussian blue/carbon dot (PB/CD) nanocomposite was synthesised and used as a visible-light active
photocatalyst for the oxidative cyanation of tertiary amines to α-aminonitriles by using NaCN/acetic acid
as a cyanide source and H2O2 as an oxidant. The developed photocatalyst afforded high yields of products
after 8 h of visible light irradiation at room temperature. The catalyst was recycled and reused several
times without any significant loss in its activity
Crystal Structure, Topological and Hirshfeld Surface Analysis of a Zn(II) Zwi...Awad Albalwi
Abstract: A mononuclear Zn(II) complex of (Zn(H2L) (CH3OH) Cl2
) (1) has been synthesized by using
a nonlinear optically active Zwitterionic Schiff base which is 4-((2-hydroxy-3-methoxybenzylidene)
amino) benzoic acid (H2L). Complex 1 has been structurally analyzed by FTIR and UV spectroscopy,
TGA, Powder-XRD and single crystal X-ray diffraction. X-Ray crystallographic studies revealed Zn(II)
complex crystallizes in a P21/c space group and exists in a distorted trigonal bipyramidal geometry
(τ = 0.68).
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
In this paper, the effect of copper oxide coated kaolinite on mercury (II) removal based on initial metal concentration, particle concentration, and prolonged residence time have been investigated. Experimental methods involved batch mode techniques at ambient temperature. The content was analysed for Hg(II) adsorbed, using standard laboratory procedures. Here, using empirical models derived from Freundlich isotherm, adsorption capacity increased from 300 to 400 mg/kg over the range of initial metal concentration investigated. The complex behavior of existing reactive sites and the generation of new active sites accounted for these changes in adsorption capacity. Increase in particle concentration led to decrease in adsorption. This was over the range of 2, 4, 6, 8 and 10 gL-1 solid concentration. Higher Cp reduced the specific surface area for adsorption. Hg(II) ions removal increased with increase in residence time. The most efficient ratio of Cu-Oxide coated kaolinite was at 0.002kgL-1 at 40mgL-1 mercury concentration. Values of between 600 to 900 mg/kg for Cu-Oxide coated kaolinite was higher when compared with the uncoated kaolinite. As ageing was increased, hydroxylation probably increased thus leading to the formation of new reactive sites.
Presentation given by Enzo Mangano of the University of Edinburgh on "Adsorption Materials and Processes for Carbon Capture from Gas-Fired Power Plants – AMPGas" at the UKCCSRC Gas CCS Meeting, University of Sussex, 25 June 2014
Presentation given by Professor Joe Wood from University of Birmingham on "Studies of Hydrotalcite Clays for CO2 Adsorption " in the Capture Technical Session on Solid Adsorption at the UKCCSRC Biannual Meeting - CCS in the Bigger Picture - held in Cambridge on 2-3 April 2014
Presentation given by Dr Hao Liu from University of Nottingham on "CO2 capture from NGCC Flue Gas and Ambient Air Using PEI-Silica Adsorbent" in the Capture Technical Session on Solid Adsorption at the UKCCSRC Biannual Meeting - CCS in the Bigger Picture - held in Cambridge on 2-3 April 2014
Adsorption separation in food processing is discussed in this presentation. Different types of adsorbent generally used are studied. Adsorption types resulting from Vander waal's forces (physisorption) and chemical forces (chemisorption) is highlighted alongwith the different adsorption isotherms- Freundlich, Langmuir and BET isotherms, as well as factors affecting adsorption like temperature, pressure and surface area.
Whether it's directly improving patient care or helping lower costs to provide more access to healthcare, organizations are continuing to use IT to move the needle for an industry that is at a pivotal point in innovation.
Learn how our innovative storage solutions can help your organization meet its healthcare Big Data challenges: http://www.netapp.com/us/solutions/industry/healthcare/
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Synthesis and Characterization of Polyaniline Doped with Cu Salts and Cu Comp...ijtsrd
In this work, we have synthesized polyaniline doped with Cu II salts and coordination complexes in presence of Aniline was polymerized in presence ammonium persulphate APS . We varied the concentration of APS and also that of Cu II salts and complexes to see the effect of these on the properties of polyaniline. We investigated the effect of the dopant and ligand around Cu II ion on the morphology, crystallinity and conductivity of the resultant polyaniline. The products were characterized by UV Vis, FT IR spectroscopy, while the morphology and crystallinity were investigated by scanning electron microscopy, and X ray diffraction studies respectively. Results show that the morphology, crystallinity and conductivity of the doped polyanilines are found to be influenced by nature of ligand. Madhab Upadhyaya | Dilip K Kakati "Synthesis and Characterization of Polyaniline Doped with Cu-Salts and Cu-Complexes" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-7 , December 2022, URL: https://www.ijtsrd.com/papers/ijtsrd52609.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/52609/synthesis-and-characterization-of-polyaniline-doped-with-cusalts-and-cucomplexes/madhab-upadhyaya
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
Reduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Reduced graphene oxide–CuO nanocomposites for photocatalyticconversion of CO2...Pawan Kumar
tReduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuOnanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probedby FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is exploredfor reduction of CO2into the methanol under the visible light irradiation. The breadth of CuO nanorods andthe oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigatetheir photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owingto fast recombination of charge carriers and yielded 175 mol g−1methanol, whereas rGO–Cu2O andrGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862 mol g−1) andseven (1228 mol g−1) folds methanol, respectively. The superior photocatalytic activity of CuO in therGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transferof photo-generated electrons through the rGO skeleton. This study further excludes the use of scavengingdonor.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after 24 h irradiation was 9934 μmol g−1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride 145 μmol g−1cat under identical conditions. The presence of triethylamine was found to be vital for the higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Carbon-cuprous oxide composite nanoparticles
were chemically deposited on surface of thin glass tubes of spent
energy saving lamps for solar heat collection. Carbon was
obtained from fly ash of heavy oil incomplete combustion in
electric power stations. Impurities in the carbon were removed by
leaching with mineral acids. The mineral free-carbon was then
wet ground to have a submicron size. After filtration, it was
reacted with concentrated sulfuric/fuming nitric acid mixture on
cold for 3-4 days. Potassium chlorate was then added drop wise on
hot conditions to a carbon slurry followed by filtration.
Nanocarbon sample was mixed with 5% by weight PVA to help
adhesion to the glass surface. Carbon so deposited was doped with
copper nitrate solution. After dryness, the carbon/copper nitrate
film was dipped in hydrazine hydrate to form cuprous oxide -
carbon composite, It was then roasted at 380-400 °C A heat
collector testing assembly was constructed of 5 glass coils
connected in series with a total surface area of 1250 cm2
. Heat
collection was estimated by water flowing in the glass coils that
are coated with the carbon/copper film,. Parameters affecting the
solar collection efficiency such as time of exposure and mass flow
rate of the water were studied. Results revealed that the prepared
glass coil has proven successful energy collector for solar heat.
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
The role of V and Mn incorporated mesoporous molecular sieves was
investigated for the vapor phase oxidation of o-xylene. Mesoporous monometallic
V-MCM-41 (Si/V = 25, 50, 75 and 100), Mn-MCM-41 (Si/Mn = 50) and bimetallic
V-Mn-MCM-41 (Si/(V ? Mn) = 100) molecular sieves were synthesized by
a direct hydrothermal (DHT) process and characterized by various techniques such
as X-ray diffraction, DRUV-Vis spectroscopy, EPR, and transmission electron
microscopy (TEM). From the DRUV-Vis and EPR spectral study, it was found that
most of the V species are present as vanadyl ions (VO2?) in the as-synthesized
catalysts and as highly dispersed V5? ions in tetrahedral coordination in the calcined
catalysts. The activity of the catalysts was measured and compared with each other
for the gas phase oxidation of o-xylene in the presence of atmospheric air as an
oxidant at 573 K. Among the various catalysts, V-MCM-41 with Si/V = 50
exhibited high activity towards production of phthalic anhydride under the experimental
condition. The correlation between the phthalic anhydride selectivity and
the physico-chemical characteristics of the catalyst was found. It is concluded that
V5? species present in the MCM-41 silica matrix are the active sites responsible for
the selective formation of phthalic anhydride during the vapor phase oxidation of
o-xylene.
Visible Light Photocatalytic Degradation of Methylene Blue and Malachite Gree...IJEAB
A facile solid state metathesis synthesis of barium tungstate (BaWO4) followed by ball milling and subsequent preparation of barium tungstate-graphene oxide (BaWO4–GO) nano composite using a colloidal blending process and its application as a visible light photocatalyst for the degradation of Malachite green and Methylene blue dyes. The morphology and composition of barium tungstate (BaWO4) nano composite have been characterized using X-Ray Diffraction (XRD), UV–Visible Diffuse Reflectance Spectra (UV-DRS), Raman Spectra, Field Emission Scanning Electron Microscopy (FESEM) – EDAX and UV Visible Spectroscopy. This composite material is found to be a wide band gap semiconductor with band gap of 4.3 eV. The sample shows poor transmittance in ultraviolet region while it has maximum transmittance in visible-near infrared regions. It shows an increase in range and intensity of light absorption and the reduction of electron–hole pair recombination in BaWO4 with the introducing of GO on to it.
The key differences between the MDR and IVDR in the EUAllensmith572606
In the European Union (EU), two significant regulations have been introduced to enhance the safety and effectiveness of medical devices – the In Vitro Diagnostic Regulation (IVDR) and the Medical Device Regulation (MDR).
https://mavenprofserv.com/comparison-and-highlighting-of-the-key-differences-between-the-mdr-and-ivdr-in-the-eu/
Company Valuation webinar series - Tuesday, 4 June 2024FelixPerez547899
This session provided an update as to the latest valuation data in the UK and then delved into a discussion on the upcoming election and the impacts on valuation. We finished, as always with a Q&A
The world of search engine optimization (SEO) is buzzing with discussions after Google confirmed that around 2,500 leaked internal documents related to its Search feature are indeed authentic. The revelation has sparked significant concerns within the SEO community. The leaked documents were initially reported by SEO experts Rand Fishkin and Mike King, igniting widespread analysis and discourse. For More Info:- https://news.arihantwebtech.com/search-disrupted-googles-leaked-documents-rock-the-seo-world/
Falcon stands out as a top-tier P2P Invoice Discounting platform in India, bridging esteemed blue-chip companies and eager investors. Our goal is to transform the investment landscape in India by establishing a comprehensive destination for borrowers and investors with diverse profiles and needs, all while minimizing risk. What sets Falcon apart is the elimination of intermediaries such as commercial banks and depository institutions, allowing investors to enjoy higher yields.
Enterprise Excellence is Inclusive Excellence.pdfKaiNexus
Enterprise excellence and inclusive excellence are closely linked, and real-world challenges have shown that both are essential to the success of any organization. To achieve enterprise excellence, organizations must focus on improving their operations and processes while creating an inclusive environment that engages everyone. In this interactive session, the facilitator will highlight commonly established business practices and how they limit our ability to engage everyone every day. More importantly, though, participants will likely gain increased awareness of what we can do differently to maximize enterprise excellence through deliberate inclusion.
What is Enterprise Excellence?
Enterprise Excellence is a holistic approach that's aimed at achieving world-class performance across all aspects of the organization.
What might I learn?
A way to engage all in creating Inclusive Excellence. Lessons from the US military and their parallels to the story of Harry Potter. How belt systems and CI teams can destroy inclusive practices. How leadership language invites people to the party. There are three things leaders can do to engage everyone every day: maximizing psychological safety to create environments where folks learn, contribute, and challenge the status quo.
Who might benefit? Anyone and everyone leading folks from the shop floor to top floor.
Dr. William Harvey is a seasoned Operations Leader with extensive experience in chemical processing, manufacturing, and operations management. At Michelman, he currently oversees multiple sites, leading teams in strategic planning and coaching/practicing continuous improvement. William is set to start his eighth year of teaching at the University of Cincinnati where he teaches marketing, finance, and management. William holds various certifications in change management, quality, leadership, operational excellence, team building, and DiSC, among others.
Implicitly or explicitly all competing businesses employ a strategy to select a mix
of marketing resources. Formulating such competitive strategies fundamentally
involves recognizing relationships between elements of the marketing mix (e.g.,
price and product quality), as well as assessing competitive and market conditions
(i.e., industry structure in the language of economics).
RMD24 | Retail media: hoe zet je dit in als je geen AH of Unilever bent? Heid...BBPMedia1
Grote partijen zijn al een tijdje onderweg met retail media. Ondertussen worden in dit domein ook de kansen zichtbaar voor andere spelers in de markt. Maar met die kansen ontstaan ook vragen: Zelf retail media worden of erop adverteren? In welke fase van de funnel past het en hoe integreer je het in een mediaplan? Wat is nu precies het verschil met marketplaces en Programmatic ads? In dit half uur beslechten we de dilemma's en krijg je antwoorden op wanneer het voor jou tijd is om de volgende stap te zetten.
[Note: This is a partial preview. To download this presentation, visit:
https://www.oeconsulting.com.sg/training-presentations]
Sustainability has become an increasingly critical topic as the world recognizes the need to protect our planet and its resources for future generations. Sustainability means meeting our current needs without compromising the ability of future generations to meet theirs. It involves long-term planning and consideration of the consequences of our actions. The goal is to create strategies that ensure the long-term viability of People, Planet, and Profit.
Leading companies such as Nike, Toyota, and Siemens are prioritizing sustainable innovation in their business models, setting an example for others to follow. In this Sustainability training presentation, you will learn key concepts, principles, and practices of sustainability applicable across industries. This training aims to create awareness and educate employees, senior executives, consultants, and other key stakeholders, including investors, policymakers, and supply chain partners, on the importance and implementation of sustainability.
LEARNING OBJECTIVES
1. Develop a comprehensive understanding of the fundamental principles and concepts that form the foundation of sustainability within corporate environments.
2. Explore the sustainability implementation model, focusing on effective measures and reporting strategies to track and communicate sustainability efforts.
3. Identify and define best practices and critical success factors essential for achieving sustainability goals within organizations.
CONTENTS
1. Introduction and Key Concepts of Sustainability
2. Principles and Practices of Sustainability
3. Measures and Reporting in Sustainability
4. Sustainability Implementation & Best Practices
To download the complete presentation, visit: https://www.oeconsulting.com.sg/training-presentations
Cracking the Workplace Discipline Code Main.pptxWorkforce Group
Cultivating and maintaining discipline within teams is a critical differentiator for successful organisations.
Forward-thinking leaders and business managers understand the impact that discipline has on organisational success. A disciplined workforce operates with clarity, focus, and a shared understanding of expectations, ultimately driving better results, optimising productivity, and facilitating seamless collaboration.
Although discipline is not a one-size-fits-all approach, it can help create a work environment that encourages personal growth and accountability rather than solely relying on punitive measures.
In this deck, you will learn the significance of workplace discipline for organisational success. You’ll also learn
• Four (4) workplace discipline methods you should consider
• The best and most practical approach to implementing workplace discipline.
• Three (3) key tips to maintain a disciplined workplace.
B2B payments are rapidly changing. Find out the 5 key questions you need to be asking yourself to be sure you are mastering B2B payments today. Learn more at www.BlueSnap.com.
Kseniya Leshchenko: Shared development support service model as the way to ma...Lviv Startup Club
Kseniya Leshchenko: Shared development support service model as the way to make small projects with small budgets profitable for the company (UA)
Kyiv PMDay 2024 Summer
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RMD24 | Debunking the non-endemic revenue myth Marvin Vacquier Droop | First ...BBPMedia1
Marvin neemt je in deze presentatie mee in de voordelen van non-endemic advertising op retail media netwerken. Hij brengt ook de uitdagingen in beeld die de markt op dit moment heeft op het gebied van retail media voor niet-leveranciers.
Retail media wordt gezien als het nieuwe advertising-medium en ook mediabureaus richten massaal retail media-afdelingen op. Merken die niet in de betreffende winkel liggen staan ook nog niet in de rij om op de retail media netwerken te adverteren. Marvin belicht de uitdagingen die er zijn om echt aansluiting te vinden op die markt van non-endemic advertising.
Personal Brand Statement:
As an Army veteran dedicated to lifelong learning, I bring a disciplined, strategic mindset to my pursuits. I am constantly expanding my knowledge to innovate and lead effectively. My journey is driven by a commitment to excellence, and to make a meaningful impact in the world.
2. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
acid-catalyzed cyclocondensation of resorcinol with
various aliphatic or aromatic aldehyde (Nikod et al.,
2009; Tustad et al., 1989 and Jain et al., 2005). The
compounds are easily synthesized by well-established
one-pot procedures (Jain et al., 2005). They have found
much application of Calix[4]resorcinarenes such as
macrocyclic receptor (Botta et al., 2005), host
molecules (Utzig et al., 2004; Kazakova et al., 2002
and Barnes et al., 2007), dying fiber (Jain et al., 2005),
building blocks for even larger supramolecular
architectures assemblies such as cages, capsule, as
starting materials for the preparation of more
sophisticated molecules (Beyeh et al., 2006) and HPLC
stationary phase (Sokolies et al., 2003 and Ruderisch et
al., 2005). Calix[4]resorcinarenes is also can be applied
as a sunscreen (Budiana et al., 2014). Nonetheless,
there are still limited reports on the utilization of
calix[4]resorcinarenes (Ruderisch et al., 2005) as
adsorbent for heavy metal cations. C-phenylcalix
[4]resorcinarenes (CPCR) is calix[4]resorcinarene
having four benzene rings and eight hydroxyl groups
(Fig. 1). CPCR was synthesized directly by acid-
catalyzed condensation of resorcinol and benzaldehyde
(Tunstad et al., 1989 and Gutshe, 1998). The presence
of lone-pair electrons in the hydroxyl groups and p-
electrons in the aromatic moieties can possibly lead to
characteristic affinities to heavy metal cations
especially Pb(II) and Cr(III). The former cation is
considered to be a softer pearson acid than Cr(III),
which was a hard pearson acid, while CPCR with
hydroxyl groups and aromatic rings can from both a
“hard” and a “soft” ion binding sites, respectively. So
the aim of this study was to investigate the interaction
of CPCR with the two said heavy metal cations (Pb(II)
and Cr(III).
2. Materials and Methods
2.1. Reagents
Metal solutions were prepared by diluting 1000
mg/L Pb(NO3)2, Cr(NO3)3 and Cd(NO3)2 standard
solutions in aqueous nitric acid to desired
concentrations. An adjustment of pH was carried out
by adding slowly NaOH or HCl solution into the metal
solutions followed by stirring until desired pH.
Chemicals needed to synthesis CPCR were resorcinol,
benzaldehyde, HCl, and ethanol absolute. All materials
required were reagent grade from E-Merck USA.
2.2. Instruments
Elucidation the structure of the synthesized
compounds was performed using Proton Nuclear
magnetic Resonance (1H-Infra Red (FT-IR Shimadzu,
Prestige 21), and Liquid Chromatography-Mass
Spectrometer (LC-MS Mariner). pH meter (Hanna)
were used for adsorption experiment and determination
of heavy metals concentration using flame atomic
absorption spectrometry.
2.3. Synthesis of CPCR
CPCR was synthesized according to the method
as described by Tunstad and co-workers (Tunstad et
al., 1989). Resorcinol (1.60 g, 0.015 mole) and ethanol
95% (50 mL) were mixed into 250 mL round bottomed
flask. The mixture was stirred for 15 minutes.
Benzaldehide 1.59 g (0.05 mol) and 1.0 mL HCl was
then added to the homogenous solution. The mixture
was heated for 24 hours at 78 o
C. The product was
collected as yellow solid, washed by water and
characterized by IR spectroscopy, 1
HNMR and mass
spectroscopy.
2.4. Adsorption Procedures
Adsorption was conducted according to the
method as described by Jumina et al (2011). Batch
system was conducted by adding 0.01 of CPCR with
particle size of 100-200 mesh into 10 mL of metal
cation sample solution having concentration of about 6
mg/L. The mixture was shaken at room temperature for
certain period of time. The adsorbent was filtered out
and dried in desiccators. Concentration of metal ion
was then measured by AAS. The data obtained was
compared and corrected by a blank solution. The blank
solution is similar to the adsorption sample except for
the existence of the adsorbent. The amount of metal
cation adsorbed was calculated from the difference
between the metal cation concentration before and after
the adsorption experiment. The metal uptake, q (mg
metal ion/g CPCR or mmol/g) was determined as
follows: q= (Co-C) x V/m or q= (Co-C) x V/(Ar x m),
where Co and C are the initial and the final
concentrations (mg/L) of metal ions, respectively; V is
the volume of solution (mL); Ar is the relative atomic
mass and m is the adsorbent weight (g) in dry form.
290
3. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
For each metal cation, the experiment was done in 3
conditions, i.e. variation of pH, shaking time, and
adsorbent concentration.
Fig. 1. Structure of CPCR
3. Results and Discussion
3.1. Synthesis and Characterization of CMCR
Synthesis of C-phenylcalix[4]resorcinarene
carried out by reacting resorcinol with benzaldehyde
using HCl catalyst in absolute ethanol solvent.
Synthesis of C-phenylcalix[4] resorcinarene reaction
is faster than C-Methylcalix[4]resorcinarene, this is
shown by the formation of deposits in 3 hours. While
C-Methylcalix[4]resorcinarene formed the deposits
after 8 hours. In the beginning of C-phenylcalix[4]
resorsinarene synthesis, H+
ion of HCl catalyst
protonate the carbonyl group of benzaldehyde to give a
carbonyl group which has positive charge. The
presence of this positive charge caused unstable
oxygen bond, therefore the electron of the double
bonding carbonyl group shift toward oxygen atom.
This shift caused the carbon atom of carbonyl group
became positively charged.
C-phenylcalix[4]resorcinarene compound
obtained in solid state, pale yellow with melting point
of > 390 o
C, insoluble in water, acetone and dichloro-
methane but soluble in DMSO. Limited solubility in
organic solvents and the great melting are caused by
many hydroxyl groups and phenyl groups in the
molecule of C-phenylcalix[4]arene. Characterization of
C-phenylcalix[4]arene by infrared spectrometer
showed that C-phenylcalix[4]arene has a strong and
broad absorption in 3387 cm-1
caused by strain
absorption of –OH groups, while the absorption in
1613 cm-1
and 1512 cm-1
area caused by absorption of
C=C in aromatic rings. Absorption of C-H methylene
bridge (-CH2-) present as a medium absorbance in
1427 cm-1
and absorption C-O present in 1204 cm-1
.
Fig. 2. 1
H-NMR Spectra of C-Phenylcalix[4]resorcinarene
291
4. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
Fig. 3. Mass s pectra of C-Phenylcalix[4]resorcinarene
Characterization of C-phenylcalix[4]arene by
using 1
H-NMR (in DMSO solvent) showed that all
protons present in corresponding shift. The bridge
proton present in 5,62 ppm, aromatic proton present
both in 6,25 and 6,81 ppm then hidroxy proton present
in 8,56 ppm. The shift in 2,55 ppm caused by DMSO
solvent and shift in 3,48 areas caused by H2O proton
that probably derived from DMSO which absorb water.
By comparing the obtain 1
H-NMR spectra of C-
phenylcalix[4]arene and 1
H-NMR spectra of C-
phenylcalix[4]resorcinarene, isomer models of C4v
dan C2v were successfully separated and characterized
by Tunstad et al. (1989), it turn out that C-phenylcalix
[4]arene products obtained only C4v (crown) isomer.
This is evident from –
OH proton of resorcinol ring
which present as a single peak in 8.53 ppm shift.
If the reaction product is C2v , the H-NMR
spectrum will appeare as a pair peak of –OH proton in
8,44 and 8,55 ppm area. IR and 1
H-NMR data are
strengthened by mass spectra data. Fragmentation
pattern of C-Phenylcalix[4]arene is a bit difficult to
predict because the molecular mass of C-
Phenylcalix[4]arene is quite high at 792 g/mole.
However, the presence of fragments may indicate that
the synthesis product is actually C-Phenylcalix[4]
resorcinarene. Fragment with the value of 482 near to
the trimers (484), 393 fragment near to the dimers
(396), 197 fragment near to the monomers (198) then
110 is resorcinol. These fragments showed that C-
Phenylcalix[4]arene molecules are decompose by the
high temperature. Mass spectra of C-
Phenylcalix[4]resorcinarene shown in Fig. 3. The
mechanism of synthesis C-Phenylcalix[4]resorcinarene
shown in Fig. 4.
Fig. 4. The mechanism of synthesis C-Phenylcalix[4]
resorcinarene
The activity test of C-Phenylcalix[4]resor
cinarene as adsorbent of heavy metals cation carried
out to determine the potential of this compound to be
applied as adsorbent of toxic metal cations include;
Cr(III) and Pb(II) both in the environment and the body
(antidotum). The test conducted by batch method
because this method is simple, inexpensive, easy to
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5. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
perform and the result can be justified. The test was
done in number of variations such as acidity degree
(pH), interaction time and also the concentration of the
metal cation. The variation of pH aims to determine the
optimum pH of the adsorption process, by the variation
of interaction time in optimum pH can be determined
the Adsorption kinetics and then by the variation of
concentration in optimum pH and interaction time can
be concluded the isotherm adsorption pattern of
benzoyl-cinnamoylcalix[4]resorcinarene also parame-
ters of adsorption.
3.2. Effect of Acidity
Acidity degree is a measured concentration of
H+
ion in a solution. The acidity degree is an important
factor in Adsorption process, because the H+
ion can be
bounded to the active sites of the base adsorbent (free
electrons pair provider). As shown in Fig. 5 at low pH
the percentage of Cr(III) cation which adsorbed by
CPCR adsorbent is still small. Percentage of the
adsorbed Cr(III) increase due to the increases of
solution’s pH. Maximum percentage of adsorbate that
adsorbed was found on the range of pH 6 to 7 which
reached 98.50%. After pH = 7, the percentage of
adsorbed Cr(III) decrease to 5.43 % on pH=8. At the
low pH, adsorbent’s ability to adsorb Cr(III) is still
small. It is because of at low pH, the concentration of
H+
ion is high and it has empty orbital so is possible to
the existence of competition with metal cations which
also act as a Lewis acid, for binding to the active sites
on the adsorbent. There are 4 hydroxyl (-OH) groups in
CPCR adsorbent which have a pair of free electrons in
every oxygen atom and aromatic ring. The competition
between H+
ions with cations of metal at low pH has
been demonstrated by Martell and Hancock (1996),
who found the complex between Ca2+
and EDTA are
just beginning to form at pH above 3, the formed
complex increased after H+
ions removed from solution
by adding NaOH solution.
The competition between H+
ions and Cr (III) in
the high acidity (low pH) can be illustrated (Fig. 6). In
reducing of acidity (increasing of pH), the
concentration of H+
ion began to decrease so that
Cr(III) started more adsorbed. The increasing Cr(III)
adsorption reached maximum in pH range of 6-7 and
started to reducing in range of pH more than 7. The
reducing of pH caused by the precipitation of Cr(III)
ions to Cr(OH)3. Adsorption ability of the test
compound seems that CPCR adsorbent can adsorb the
Cr(III) by approximately 98.50%. This is caused by
conformity of acid-base properties between adsorbent
and adsorbate. The adsorbent has many –OH group
which are hard base while Cr(III) is hard acid. This is
in quite good agreement with Handayani (2011) which
state that in generally the hard base will form a stable
Fig. 5. Effect of initial pH on the adsorption of Cr(III) and Pb(II) onto CPCR
293
6. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
Fig. 6. Interaction between adsorbent and Cr(III) in low pH
bond with hard acid. The stable bond between the hard
base adsorbent and the hard adsorbate associated with
large energy differences between hard acids and bases
orbitals. The large energy differences leading a charge
transfer process from alkaline to acidic in highly
exothermic, resulting an ionik interaction. This ionic
interaction caused the bond between the adsorbent with
the adsorbate is difficult to detaching.
Acidity effect to the Pb(II) cation adsorption
by CPCR showed in Fig. 5 shown that CPCR begin to
adsorb Pb(II) cation at pH of 2 and this is somewhat
different with Cr(III) cations which are just beginning
to be adsorbed by the adsorbent at pH of 3.Just like to
the Adsorption of Cr(III) cation, in low pH or in the
high acidity, percentage of adsorbed Pb(II) cation is
still small. This is caused by existence of competition
between H+
of acid with Pb(II) cations (Fig. 6).
Because of the acidic nature of H+
ion is higher than
the Pb (II), the Pb (II) lost the competition for binding
to the sides of the active adsorbent which is alkaline.
The H+
ions are covalently bound to the active cluster
coordination of the adsorbent so the adsorbent
consequently positively charged. This is what causes
the occurrence of electrostatic repulsion between the
protonated adsorbent with Pb (II) so that the adsorption
process could not be run properly. Adsorption of Pb(II)
cation by five CPCR lower than the cation Cr (III) this
is in line with the nature of Pb (II) which is a metal
with medium acidity that will bind properly when the
adsorbent also has many active group with medium
alkalinity such as N2, N3, NO2, C6H5NH2 and Br.
3.3. Effect of Interaction Time
Effect of interaction time between
calix[4]resorcinarene (adsorbent) with metal’s cation
(adsorbate) is important to be studied in order to
determine the reaction kinetics of Adsorption. Through
the determination of interaction time effect on the
percentage of adsorbed adsorbate, will be known the
time required by adsorbate to reach equilibrium.
After reacher the equilibrium, adsorption rate
comparable to the rate of the release adsorbate so that
in this state the percentage of the adsorbed adsorbate
relatively constant. The curve in the Fig. 7 showed that
at the first 5 minutes, adsorbent can adsorb Cr(III)
above 50%. After the increase of interaction time, in
generally the adsorbed Cr(III) also increase. This is
concluded that there are free active sites so the
adsorbent still adsorb at any given time the percentage
of adsorbed metal cation not significantly increased. In
this condition, the adsorption process is said to have
reached an equilibrium state. The equilibrium state is
achieved due to the adsorption rate that has been offset
by the rate of desorption. Fig. 7 shows that the
optimum time of adsorption on the adsorbent CPCR
reached in the 45th
minute, the percentage change of Cr
(III) adsorbed to the next time is not too great.
In the Adsorption process of Pb(II) by CPCR,
the equilibrium state reached in the 405th
minutes. It
take a lot of time to reached the equilibrium state
shows that Adsorption rate of Pb(II) by the adsorbent is
slow. Slow reaction rate is according to the dispra-
pances properties of adsorbent and Pb(II) cation. All
294
7. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
Fig. 7. Effect of interaction time on the adsorption of Cr(III) and Pb(II) onto CPCR
adsorbents have active site in the form of hard alkaline,
while Pb(II) is a cation with intermediate alkaline
properties. If Judging from the achievement of
equilibrium time that take a lot of time which almost 7
hours, the from the economic stand point those
adsobent are less favorable to applied for Pb(II)
Adsorption. Long reaction time certainly required a lot
of effort and operational cost.
The conclusion about the kinetics model
followed in the adsorption experiments are based on
the value of the correlation coefficient (R2) for each
model. Largegren model studied by passing log (qe –
qt) as ordinate with t(time) as the axis X. qe value is
the adsorbed mass at equilibrium state (mg/g) and qt is
the adsorbed mass at the time t. Slope value of
Largegren is the rate constant (k). Ho Models studied
by passing the value of (Y axis) with the time t, and as
the value of slope.
Correlation coefficient showed that almost all
Ho model have R2 value close to 1 and larger than R2
value of Largegren. Based to these data, the reaction
rate of both Cr(III) and Pb(II) cations by CPCR are
determined by the active sites quantity of adsorbent
and also adsorbate concentration. Value of rate
constant (k) is measured by intersection between X-
axis (time) and Y-axis (time(t)/adsorption mass at time
(qt) by determined the adsorption mass at equilibrium
state of slope first). The measurement of rate constant
important to be done to determine the interaction rate
that occurs between adsorbent and metal’s cation. The
CPCR rate constant of reaction (k) in Adsorption of
Cr(III) and Pb(II) are 15.36 x 10-4
and 4.18 x 10-4
respectively.
3.4. Effect of Metal Ion’s Concentration and Iso-
thermal Adsorption
Metal Ion’s Concentration effect at optimum pH
and time also at constant temperature aim to determine
isotherm model followed by adsorption process of
CPCR to Cr(III) and Pb(II) cations. Based to the
followed isotherm pattern, there can be measure the
maximum adsorption capacity (Xm), Adsorption
energy (E) and equilibrium constant (K). The
adsorption models studied in this research are
Freundlich and Langmuir isotherm adsorption. In the
Freundlich isotherm the adsorption process is
multilayer which the adsorbent with unlimited
concentration able to unlimited adsorb the adsorbate.
While in the model of Langmuir isotherm
adsorption, the adsorption process takes place
gradually until it meets the surface and form a single
layer (monolayer) caused by the interaction between
the adsorbate with the active sites of the adsorbent.
When all of the active sites already binds the
adsorption does not happen again, because the surface
of the adsorbent is considered saturated. Freundlich
295
8. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
isotherm models defined by the equation;
Ce
n
Kqe log
1
loglog
Where qe is the adsorbate concentration
adsorbed by adsorbent at the equilibrium states
(mole/g) which the units cn be convert into mole/L. Ce
is the concentration of adsorbate in liquid state
(mole/L). By passing qe as the ordinate and Ce as the
abscissa then the value of equilibrium constant (K) and
amount of n layer can be measured by the intersection
and the slope. Langmuir isotherm models defined by
the equation;
Xm
Ce
KXmq
Ce
e
.
1
The passing of Ce/qe as Y-axis and Ce/Xm then
can be determined the value of equilibrium constant
(K) from the value of intersection and maximum
Adsorption capacity Xm from the slope. The important
parameter to be measured in studied of ishoterm
adsorption is equilibrium constant (K), maximum
adsorption capacity (Xm) and adsorption energy (E).
Equilibrium constant related to the comparison
between concentrations of reaction product and
remains reactant at the equilibrium state. If the value
of K is larger it means the reaction tend to shift toward
product, in this case complex between adsorbent and
adsorbate. Otherwise, if the value of K is smaller the
equilibrium reactions tend to shift toward reactant
which also means that metal ion tend to be release
again. Maximum adsorption capacity (Xm) value is
also important to be measured because it involves the
ability of an adsorbent in adsorbing metal cations. The
effect of concentration on the adsorption of Cr(III) and
Pb(II) onto CPCR described in Fig. 8.
Fig.8. The effect of concentration on the adsorption of Cr(III) and Pb(II) onto CPCR
Table 1. Values of K, Xm and E in Adsorption of Cr(III) and Pb(II) by CPCR Adsorbent
296
9. Budiana et al. /J Applied Chem. Sci. 3 (2016) 289-298
The curve in the Fig. 8 showed that at the Cr(III)
concentration (5 ppm), all of the Cr(III) ion can
adsorbed by CPCR. It caused by the amount of active
site of the adsorbent too much greater than amount of
the metal ions. The greater concentration the smaller
amount of the metal that is absorbable by CPCR. It was
caused by the saturation of the active site of CPCR.
The values of K, Xm and E are tabulated in Table 1.
The greater adsorption capacity means the
adsorbent is better, this is because the increases of
adsorbate quantity that adsorbed by an adsorbent.
Value of adsorption energy (E) indicates the type of
adsorption involved, because value of E measured by
Gibbs energy equation; ∆G = -RT ln K. R is an ideal
gas constant (8.314 J/K mol), T is the temperature in
Calvin and K is the equilibrium constant. Adsorption
energy more than 20 kJ/mole indicate that the involve
adsorption is a chemical adsorption. Energy adsorption
value less than 20 kj/mole indicate that the involve
reaction is a physic adsorption. Chemical adsorptions
occur by the strongly chemical bond between
adsorbent and adsorbate. The chemical bond can be
pure covalent bonds, ionic bonds or hydrogen bonds.
The adsorption energy data in table 1 showed
that all adsorption energies are more than 20 kJ/mole.
Based to this adsorption data, the adsorption type in
adsorption process of Cr(III) and Pb(II) metals by
adsorbent are chemical adsorption. In the reaction
between adsorbed solid and soluble substance, this
adsorption is specifically and involve the greater force
than the physic adsorption.
The adsorption of metal cation such as Cr(III),
Pb(II) and Cd(II) by CPCR are following Langmuir
isotherm adsorption model as indicated in the V
attachment. According to Langmuir, the adsorbed
molecules are detained on the surface by the same
valence force as occur in the atoms of molecule. By the
presence of a chemical bond then in the surface of the
adsorbent will be formed a layer wherein the formation
of the layer will further inhibit the absorption process.
4. Conclusion
C-Phenylcalix[4]resorcinarene (CPCR) could be
synthesized only in one step of the reaction i.e.
condensation of the resorcinol with benzaldehyde
using HCl catalyst. The adsorption experiments in
batch system were investigated that acidity level
influence significantly the adsorption. The study of
kinetic adsorption showed that CPCR followed the
kinetic model of Ho. The results of adsorption
equilibrium study showed that in adsorption Cr(III) and
Pb(II) onto CPCR, Langmuir isoterm model was more
applicable than Freundlich model. The tested
adsorbents show that CPCR has a good ability in
adsorption of Cr(III) (98.50%) and Pb(II) (65.8%)
cations.
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Source of support: None Declared
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