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Volume 6, Issues 2, 3, (March – June 2017)

Investigation of the Removal Characteristics of Cr(VI) by Used Black Tea Leaves from Aqueous System


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 31–36

Mohammad Abul Hossain*, Mikio Kumita, Shigeru Mori

 

Abstract

The removal characteristics of hexavalent chromium from aqueous solution by used black tea leaves (UBTL) as a low cost adsorbent were investigated. Effects of various operating factors such as solution pH, adsorbate concentration, contact time, temperature, adsorbent size, etc. on this removal process were studied in batch process. As both adsorption and reduction involved in the removal process, were strongly influenced by the initial solution pH. Equilibrium and kinetic studies were carried out in the low pH range of 1 to 2, where the adsorption was predominant over the reduction. The equilibrium adsorption data were well expressed by Langmuir equation and the maximum adsorption capacity was calculated that showed the extremely high adsorption capacity of UBTL (454 mg×g-1) which is increased with increase in temperature. Adsorption kinetics was well expressed by pseudo-second order kinetic model. Both the adsorption capacity and the rate of adsorption were significantly affected by adsorbate concentration and adsorbent size. The investigation of transport mechanism has shown that the adsorption was controlled by the surface chemical reaction at low concentration of Cr(VI) and the intraparticle diffusion was at high Cr(VI) concentration. SEM and EDX analyses of Cr(VI) adsorbed UBTL surface revealed that the Cr(VI) are not homogeneously adsorbed on heterogeneous UBTL surface.

 

Keywords: Adsorption; Reductin; Hexavalent Chromium; Used Black Tea Leaves; Equilibrium; Kinetics; SEM and EDX. 

Received

  Accepted
31 January 2017
29 March 2017

Importance of Hydrophobic Interactions on the Luminescence Quenching of Ru(ii)-Polypyridyl Complexes with Phenolic Acids and Quercetin in Triton X-100


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 37–45

Sheeba Daniel and G. Allen Gnana Raj *

 

 

Abstract

Photoinduced electron transfer reactions between the excited state Ru(II)-polypyridyl complexes {[Ru(bpy)3]2+ (bpy=2,2'-bipyridine), [Ru(dmbpy)3]2+ (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) and [Ru(dtbpy)3]2+ (dtbpy = 4,4'-di-ter-butyl-2,2'-bipyridine)} and phenolate ions of polyphenols (gallic acid, quercetin, p-coumaric acid and ferulic acid) has been investigated in Triton X-100 at pH 11 using luminescent quenching technique. The absorption and emission maximum of these complexes are in the range of 449-457 nm and 612-639 nm respectively. The static nature of quenching of these complexes with gallic acid and quercetin are confirmed from the ground state absorption studies. The association constant (Ka) for [Ru(bpy)3]2+, [Ru(dmbpy)3]2+ and [Ru(dtbpy)3]2+ complexes with gallic acid and quercetin in Triton X-100 is calculated from the Benesi-Hildebrand plots obtained from absorption spectral data. The observed quenching rate constant (kq) values are sensitive to the nature of the ligand, medium, the structure of the quenchers and the electron transfer distance between the complex and the quencher. Triton X-100 slightly accelerates the kq of [Ru(dmbpy)3]2+ and [Ru(dtbpy)3]2+ complexes than [Ru(bpy)3]2+ complex to some extent, confirming the predominance of hydrophobic interactions of these complexes in neutral micelle. The reductive quenching of Ru(II)-polypyridyl complexes by phenolate ions has been confirmed from transient absorption spectra. The formation of phenoxyl radical as transient is confirmed by its characteristic absorption at 400 nm.

 

 

Keywords: Luminescence quenching; Association constant; Stern-Volmer equation; Structural effects; Hydrophobic interaction.

Received
Accepted
18 January 2017
22 February 2017

Elastic and Acoustic Properties of Hexagonal M5Si3 (M = Ti, Zr) Intermetallic Compounds


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 46–50

Pramod Kumar Yadawa*   

 

 

Abstract

The ultrasonic properties like ultrasonic sound velocity in the hexagonal M5Si3 (M= Ti, Zr) intermetallic compounds has been studied along unique axis at room temperature. The second- and third order elastic constants (SOEC & TOEC) have been calculated for this compound using Lennard–Jones potential. The velocities VL and VS1 have minima and maxima respectively at 45° with the unique axis of the crystal while VS2 increases with the angle from the unique axis.. The inconsistent behaviour of angle dependent velocities is associated to the action of second order elastic constants. Debye average sound velocities of M5Si3 are increasing with the angle and has maximum at 550 with unique axis at room temperature. Hence when a sound wave travels at 550 with unique axis of M5Si3 compounds, then the average sound velocity is found to be maximum. The mechanical properties of Ti5Si3 are better than Zr5Si3 at room temperature, because it has high ultrasonic velocity and low ultrasonic attenuation. The comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of this compound.

 

 

Keywords: Intermetallic compounds; Elastic constants; Longitudinal waves, Surface waves.
Received
 Accepted
31 January 2017
31 March 2017

Growth, Thermal, Linear and Nonlinear, Dielectrics, Microhardness, Refractive Index and Laser Damage Threshold Studies on Urea Phosphoric Acid (UP) Single Crystals


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 51–57

N. Hema, R. Usha, D. Shalini, V. Revathi Ambika, D. Jayalakshmie *

 

 

Abstract

An organic nonlinear optical Urea phosphoric acid (UP) single crystal has been grown by slow evaporation solution growth technique. The cell parameters of UP single crystal and crystalline perfection were confirmed by single and High resolution X-ray diffraction analyses. The presence of functional groups was identified by FT-IR spectral analysis. The UV-Vis spectral studies showed that the UP single crystal has wide transmission window in the entire visible region. The dielectric property of UP crystal revealed the normal dielectric behaviour. Mechanical strength of UP crystal was studied. The refractive index of UP crystal was measured. The laser damage threshold value of UP crystal was found by Nd:YAG laser.The photoconductivity studies were taken. The second order nonlinear coefficient of the grown crystal was also measured for UP single crystal.

 

 

Keywords: Powder X-ray diffraction; Solubility; Growth from solutions; Organic compounds; Nonlinear optical material; Second harmonic generation. 

Received
 Accepted
11 January 2017
19 April 2017

Improvement of the Abrasive Wear Resistance of Pump Shaft (AISI 316L stainless steel) by Salt Bath Nitriding


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 58–63

Ghelloudj Elhadj*, Hannachi Mohamed Tahar, Djebaili Hamid, Hafsaoui Sifeddine          

 

 

Abstract

Centrifugal pumps are prevalent for many different applications in the industrial or other sectors. The paper reviews the literature available on the improvement of efficiency of centrifugal pump through improvement in performance of pump shaft (AISI 316L stainless steel). The paper discusses the available material of performance improvement through amelioration of tribological characteristics of pump shaft and mainly focuses on the abrasive wear resistance of AISI 316L stainless steel. In order to improve the abrasive wear resistance of stainless steel components, carbide-hardened surfaces were produced on AISI 316L austenitic stainless steel by salt bath nitriding. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperature (580°C) for 10 h. The microstructures, abrasive wear resistance, as well as its surface hardness, were investigated using optical microscopy, tribometer tester and microhardness tester. The results confirmed that salt bath nitriding  was effective in improving the abrasive wear resistance.

 

 

Keywords: Centrifugal pumps; pump shaft; AISI 316L stainless steel; Abrasive wear resistance; Salt bath nitriding.

Recived
 Accepted
11 March 2017
  29 April 2017

Green Method for Synthesis of Magnetic Hollow Silica Spheres


Original Research


Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 64–68

Ashok Nerell *

 

 

Abstract

The magnetic hollow silica spheres (MHSS) with uniform cavity size and shell thickness were prepared by a simple and “green” method using functionalized SiO2 spheres as templates. Magnetic particles (Fe3O4) were deposited on the SiO2 surface by varying the molar ratio of [Fe2+]/[Fe3+] and the molar concentration of iron salts. The obtained magnetic hollow silica spheres exhibited a super-paramagnetic behavior at room temperature. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder scattering (XRD) were applied to characterize the MHSS. Besides, their unit cell parameters are calculated according to results indexing to XRD, the MHSS sample prepared at 0.10 M iron salts and 2:1 molar ratio of [Fe2+]/[Fe3+] has a largest cell angle (β) of unit cell. Due to large hollow cavity space and super-paramagnetic characteristics, the inner amino-functionalized MHSS could be labeled with radioisotope 99Tcm to study the MHSS’s magnetic targeting distribution in vivo. These results indicate that the MHSS has potential in the magnetic targeted drug delivery system which reduces the damage to normal cells and improves the therapeutic effect of cancer.

 

 

Keywords: MHSS; Magnetic particles (Fe3O4); SEM and TEM. 

Recived
 Accepted
31 January 2017
  12 May 2017

Transport Analysis For Separation of Ni(II) Ions By Emulsion Liquid Membrane Using (LIX-84 +PC-88A)/Cyclohexane, Citric, Tartaric and Glycolic acids As Stripping phase

Original Research

Journal of Chemistry and Materials Research Vol. 6 (2,3), 2017, 69–78

Nessem El-said, Amany T. Kassem*, Mahmoud M. Ali

 

 

Abstract

Emulsion Liquid Membrane is an advancing to traditional operations for separating of nickel metal ions from simulated wastewater. The influence of different parameters, such as the feed phase, surfactant span 80/85 (3:1), metal ion concentration, pH of the continuous phase, carrier concentrations and the influence of the internal stripping agents has been realized on the extraction of Ni(II). The removal of Ni(II) from solutions by an emulsion liquid membrane technique  has been achieved through synergistic seperationby  two extractants(1%2-hydroxy-5-nonylaceto phenone oxime (LIX-84) and (4% ethylhexyl hydrogen -2- ethylhexyl phosphonate (PC-88A)  dissolved in xylene. The results elucidate that the optimum emulsion liquid membrane extraction under stripping condition was 94% of nickel(II) at the first 4 min of operational time. The ELM showed high stability up to 15 days. Due to the synergism of carriers and different stripping agents, we found that the separation of nickel using stripping agents follows the order that  citric acid>tartaric acid>glycolic acid, respectively.

 

 

Keywords: Separation of Ni (II), Synergy carrier, LIX-84 and PC- 88A, Citric, Tartaric and glycolic acids as stripping phase, Emulsion Liquid Membrane.

Recived
 Accepted
31 January 2017
  23 May 2017

Micellar Effect on the Photoinduced Electron Transfer Reactions of Ruthenium(ii) -Polypyridyl Complexes with Quinones

 

Original Research


Journal of Chemistry and Materials Research Vol. 6 (2-3), 2017, 79–82

T. Sumitha Celin and G. Allen Gnana Raj*

 

 

Abstract

Photoinduced electron transfer reactions of Ru (II) polypyridyl complexes with quinones  have been studied in micellar and aqueous medium by luminescent quenching technique.  The quenching rate constant kq is sensitive to the nature of the quencher and ligand, size of the ligand, the electron transfer distance between the complex and the quencher distance, the reduction potential of the quinones.  The electrostatic interaction between the Ru complex and the micellar medium alters the kq value when compared to that of in aqueous medium.  The quenching rate constant is altered in anionic micellar medium because the negatively charged quencher will approach the micelle bound dipositive  Ru (II) complex due to the negative charge of the anionic micelle.

 

 

Keywords: Quinones; Luminescence quenching; Stern -Volmer plot; Micelles. 

Recived
 Accepted
25 March 2017
05 June 2017