scholarly journals Electrodeposition of Hydroxyapatite Coatings for Marble Protection: Preliminary Results

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 207 ◽  
Author(s):  
Enrico Sassoni ◽  
Giulia Masi ◽  
Maria Bignozzi ◽  
Elisa Franzoni
Keyword(s):  
Protective Efficacy ◽  
Aqueous Solubility ◽  
Synthesis Methods ◽  
Working Electrode ◽  
Hydroxyapatite Coatings ◽  
Coating Morphology ◽  
Incomplete Coverage ◽  
Ft Ir ◽  
Wet Synthesis ◽  
Marble Surface

Surface coatings made of hydroxyapatite (HAP) have been proposed to protect marble artworks from dissolution in rain, originated by the aqueous solubility of calcite. However, HAP coatings formed by wet chemistry exhibit incomplete coverage of marble surface, which results in limited protective efficacy. In this study, electrodeposition was explored as a new route to possibly form continuous coatings over the marble surface, leaving no bare areas. Electrodeposition was performed by placing marble samples in poultices containing the electrolyte (an aqueous solution with calcium and phosphate precursors) and the electrodes. The influence of several parameters was investigated, namely the role of the working electrode (cathode or anode), the distance between the marble sample and the working electrode, the deposition conditions (potentiostatic or galvanostatic), the electrolyte composition and concentration, the applied voltage, and time. The coating morphology and composition were assessed by SEM/EDS and FT-IR. The protective ability of the most promising formulations was then evaluated, in all cases comparing electrodeposition with traditional wet synthesis methods. The results of the study suggest that electrodeposition is able to accelerate and improve formation of HAP coatings over the marble surface, even though the obtained protective efficacy is not complete yet.

Intact Ultrathin Ni Films Fabricated by Electroplating with Supercritical CO2 Emulsion

2013 ◽  
Vol 284-287 ◽  
pp. 147-151
Author(s):  
Tso Fu Mark Chang ◽  
Takashi Nagoshi ◽  
Chiemi Ishiyama ◽  
Tatsuo Sato ◽  
Masato Sone
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Grain Refinement ◽  
Deposition Time ◽  
Reactive Species ◽  
Complete Coverage ◽  
Transport Efficiency ◽  
Working Electrode ◽  
Incomplete Coverage

Ultrathin (2 emulsion (SCE). Incomplete coverage of the Cu plate, the working electrode, by electroplated Ni and non-uniform Ni films with defects were obtained when conventional electroplating at 1 A/dm2 with 30 sec of deposition time was used. When electroplating with SCE (ESCE) was applied, complete coverage, defect-free and uniform UTNFs were obtained. SEM and AFM showed surface morphology of the UTNFs was covered by spherical-shaped particles with ~10 nm in diameter, which was expected to be individual Ni grains because the size was consistent with grain size of Ni films reported when ESCE was applied. High H2 solubility in CO2, periodic-plating-characteristic after applying ESCE, and improved transport efficiency of the reactive species are believed to be the main reasons to cause effects of grain refinement and suppression in formation of the defects. Thickness of the UTNFs was 11.97±1.82 nm when the deposition time was 15 sec, and the thickness increased to 38.45±1.71 nm when the deposition time was increased to 45 sec.

scholarly journals Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 774
Author(s):  
Eleonora Sočo ◽  
Dorota Papciak ◽  
Magdalena M. Michel ◽  
Dariusz Pająk ◽  
Andżelika Domoń ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Synthesis Conditions ◽  
High Calcium ◽  
Ft Ir ◽  
Ir Analysis ◽  
Wet Synthesis

(1) Hydroxyapatite (Hap), which can be obtained by several methods, is known to be a good adsorbent. Coal fly ash (CFA) is a commonly reused byproduct also used in environmental applications as an adsorbent. We sought to answer the following question: Can CFA be included in the method of Hap wet synthesis to produce a composite capable of adsorbing both heavy metals and dyes? (2) High calcium lignite CFA from the thermal power plant in Bełchatów (Poland) was used as the base to prepare CFA–Hap composites. Four types designated CFA–Hap1–4 were synthesized via the wet method of in situ precipitation. The synthesis conditions differed in terms of the calcium reactants used, pH, and temperature. We also investigated the equilibrium adsorption of Cu(II) and rhodamine B (RB) on CFA–Hap1–4. The data were fitted using the Langmuir, Freundlich, and Redlich–Peterson models and validated using R2 and χ2/DoF. Surface changes in CFA–Hap2 following Cu(II) and RB adsorption were assessed using SEM, SE, and FT-IR analysis. (3) The obtained composites contained hydroxyapatite (Ca/P 1.67) and aluminosilicates. The mode of Cu(II) and RB adsorption could be explained by the Redlich–Peterson model. The CFA–Hap2 obtained using CFA, Ca(NO3)2, and (NH4)2HPO4 at RT and pH 11 exhibited the highest maximal adsorption capacity: 73.6 mg Cu/g and 87.0 mg RB/g. (4) The clear advantage of chemisorption over physisorption was indicated by the Cu(II)–CFA–Hap system. The RB molecules present in the form of uncharged lactone were favorably adsorbed even on strongly deprotonated CFA–Hap surfaces.

scholarly journals Synthesis of L-DOPA Based Melanins with Reproducible Physic-Chemical Properties

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Jayla Moore
Keyword(s):  
Ir Spectroscopy ◽  
Enzymatic Synthesis ◽  
Chemical Properties ◽  
Size Exclusion ◽  
Synthesis Methods ◽  
Ongoing Research ◽  
Vis Spectroscopy ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

This report expands our ongoing research efforts into the non-enzymatic synthesis of melanins. We have explored four different methods for the synthesis of L-DOPA based melanins and evaluated the reproducibility of some of their physic-chemical properties. The melanins were synthesized through the addition of NaOH, tyrosinate or Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>. Two different approaches for the reactions involving Fe<sup>2+</sup> and H<sub>2</sub>O<sub>2</sub> were tested: a) addition of H<sub>2</sub>O<sub>2</sub> spread out over multiple days or b) addition of H<sub>2</sub>O<sub>2</sub> in one fraction at the start of the reaction. The physic-chemical properties of the melanins explored involved: 1) retention on size exclusion chromatography column, 2) FT-IR spectroscopy, 3) UV-Vis spectroscopy and 4) the capacity to reduce a redox dye, dichlorophenolindophenol. Overall the results obtained indicated that 1) the various synthesis methods lead to melanins with reproducible physic-chemical properties, 2) that the melanins synthesized in the presence of Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub> are distinctly different from the melanins synthesized in the presence of NaOH or tyrosinate and 3) that no distinctly different melanins were generated when comparing the two different synthesis approaches involving Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>. Only the melanins synthesized in the presence of Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub> appeared to possess the capacity to reduce dichlorophenolindophenol.

Inclusion Complex of Dibenzoylmethane with β-Cyclodextrin

2011 ◽  
Vol 239-242 ◽  
pp. 1879-1882
Author(s):  
Xue Zhen Ji ◽  
Hui Jun Liu ◽  
Li Li Wang
Keyword(s):  
Inclusion Complex ◽  
Liquid Medium ◽  
Drug Loading ◽  
Aqueous Solubility ◽  
Physical Mixture ◽  
Solid Samples ◽  
Dissolution Properties ◽  
Inclusion Rate ◽  
Ft Ir

The inclusion complex of dibenzoylmathane(DBM)with β-cyclodextrin(β-CD)was studied. UV-spectrophotometer was used to investigate the complexation behaviour in liquid medium, and to demonstrate that the DBM aqueous solubility increased 7.27times due to complexation with β-CD and the inclusion rate of DBM was high to 95.92 percent and the drug-loading constant is also high to 37.86ug/g. Solid samples prepared by solution-agitating method. FT-IR was employed to assess the formation of the inclusion complex. Dissolution analysis indicated that dissolution properties of DBM/β-CD complex were superior compared to both pure DBM and the corresponding physical mixture of DBM and β-CD.

Copper Binding to Bilirubin as Determined by FT-IR and EPR Spectroscopy

1996 ◽  
Vol 50 (7) ◽  
pp. 922-927 ◽  
Author(s):  
J. R. Ferraro ◽  
J.-G. Wu ◽  
R. D. Soloway ◽  
W.-H. Li ◽  
Y.-Z. Xu ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Aqueous Solubility ◽  
Free Radical Scavengers ◽  
Copper Binding ◽  
Radical Scavengers ◽  
Paramagnetic Resonance ◽  
Physical Measurements ◽  
Stretching Vibration ◽  
Ft Ir ◽  
Electron Paramagnetic

Copper is known to form complexes with bilirubin (H2BR). Such complexes have received increased attention because of their clinical significance as free-radical scavengers. The purpose of this study was to examine a series of Cu2+ BR complexes to ascertain the nature of the binding between Cu2+ and BR. Several physical measurements of the salts were made, such as Fourier transform infrared (FT-IR) and electron paramagnetic resonance (EPR). The complexes were prepared by dissolving protonated BR in NaOH and adding different ratios of aqueous CuCl2. At ratios of Cu2+/H2BR of 1:1 and 2:1, soluble complexes were formed. In solution, EPR spectra demonstrated nine hyperfine peaks, which, from the splitting, is indicative of Cu2+ coordinated to four nitrogen atoms coming from two molecules of BR. The solid obtained from the solutions demonstrated predominant infrared absorptions at 1574 and 1403 cm−1 (previously assigned as COO− vibrations, asymmetric and symmetric), whereas the 1710-cm−1 vibration appears only as a shoulder (previously assigned as the free COOH vibration), indicative that most of the COO− groups have reacted with sodium, thus accounting for the aqueous solubility. The NH stretching vibration in the pyrrole group of H2BR has disappeared and is replaced with the OH stretching vibration in H2O. At higher ratios of 3:1 and 5:1 (Cu2+/H2BR), black precipitates are formed, which produce no EPR signals. Furthermore, the NH vibration disappears as in the soluble solution complexes. It can be concluded that the insoluble salts (higher Cu2+/H2BR ratios) are mixed complexes containing the Cu–nitrogen chelate and Cu salts involving the COOH groups.

scholarly journals Inclusion Complex of Gedunin-2-Hydroxypropyl-Β-Cyclodextrin Prepared by Kneading and Freeze-Drying Methods: Synthesis and Structural Characterization

2021 ◽  
Vol 4 (1) ◽  
pp. 83-97
Author(s):  
Mary Olufunmilayo Ologe ◽  
Adedibu Clement Tella ◽  
Olubunmi Atolani ◽  
Olajire Aremu Adegoke ◽  
Olusegun George Ademowo
Keyword(s):  
Inclusion Complex ◽  
Oral Administration ◽  
Elemental Analysis ◽  
Freeze Drying ◽  
Aqueous Solubility ◽  
Drying Methods ◽  
Cyclodextrin Complex ◽  
H Nmr ◽  
Ft Ir ◽  
Pharmacologically Active

Abstract The potential application of gedunin, a pharmacologically active limonoid, is limited in medicine because it has poor aqueous solubility. This study was aimed at preparation and characterization of an inclusion complex of gedunin and 2-hydroxypropyl-β-cyclodextrin (HBD) to increase the solubility in aqueous solvents and thus enhance the possibility of pharmaceutical formulation and oral administration of gedunin. Inclusion complex of gedunin isolated from Entandrophragma angolense heartwood with 2-hydroxypropyl-β-cyclodextrin (HBD) was prepared using freeze-drying and kneading methods. The gedunin-2-hydroxypropyl-β-cyclodextrin complex (GCD) was characterized using elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H-NMR) and X-ray diffraction analysis (XRD). Elemental analysis indicated that gedunin and HBD formed 1:1 stoichiometric inclusion complex. Results of FT-IR indicated that gedunin was stabilized in HBD cavity by intra-molecular hydrogen bonds and van der Waals forces. 1H-NMR revealed that the entire gedunin molecule was not trapped into the core of the HBD. Nevertheless, the fraction trapped may be sufficient to enhance the apparent solubility of gedunin. XRD results showed the formation of new solid crystalline phase. The results obtained by different characterization techniques clearly indicated that both kneading and freeze-drying methods led to inclusion complex formation which may enhance oral administration of gedunin.

scholarly journals Ag2O/GO/TiO2 Composite Nanostructure: an efficient heterogeneous catalyst for one pot synthesis of Bis (dihydropyrimidinone) and tetrahydro-4H-chromenes derivatives

2021 ◽  
Author(s):  
Fatemeh Samandi Zadeh ◽  
Mohammad Kazem Mohammadi ◽  
Ayeh Raeiatzadeh ◽  
Neda Hasanzadeh
Keyword(s):  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
One Pot ◽  
Transmission Electron ◽  
One Pot Condensation ◽  
Effective Synthesis ◽  
Ft Ir ◽  
Biginelli Condensation

Abstract The simple and efficient synthesis reaction was used for preparing Bis (dihydropyrimidinone) derivatives through Biginelli condensation reaction of terephthalic aldehyde, 1, 3-dicarbonyl compounds and (thio) urea or guanidine and tetrahydro-4H-chromenes via one pot condensation of aromatic aldehydes, malononitrile and dimedone with Ag2O/GO/TiO2 composite nanostructures as a catalyst. The structural functionalities and morphological observations of catalyst were obtained using characterization techniques of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transfer infrared (FT-IR) spectroscopy and transmission electron microscope (TEM). The structures of Bis (dihydropyrimidinone) and tetrahydro-4H-chromenes confirmed by FT- IR, NMR and mass spectroscopy. Excellent yields of the products, simple reaction process and simple work-up are attractive features of these effective synthesis methods.

Synthesis, structure and magnetism of a new ionic pentanuclear iron cluster

2020 ◽  
Vol 76 (7) ◽  
pp. 690-694
Author(s):  
Qianjun Deng ◽  
Jiming Wang ◽  
Guangzhao Li ◽  
Shuhua Zhang
Keyword(s):  
Thermogravimetric Analysis ◽  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Iron Cluster ◽  
X Ray ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

A new ionic pentanuclear FeIII cluster, namely, triethylazanium tetrakis(μ2-5-amino-1,2,3,4-tetrazolido)tetrakis(μ3-4-chloro-2-{[(1H-tetrazol-1-id-5-yl)imino]methyl}phenolato)di-μ3-oxido-pentairon(III) acetonitrile monosolvate monohydrate, (C6H16N)[Fe5(C8H4ClN5O)4(CH2N5)4O2]·CH3CN·H2O, was synthesized using microvial synthesis methods and characterized by elemental analysis, FT–IR spectroscopy, single-crystal X-ray diffraction and thermogravimetric analysis. Magnetic studies reveal that the complex displays dominant antiferromagnetic intracluster interactions between the FeIII ions through the μ3-oxide bridges.

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