Vol. 18(9) September 2014
Effect of Molecular Properties on the Photocatalytic
Degredation Rates of Pyridazine
Gulsen A. and Gurkan Y. Y.
In this study, with the intention of determining the
primary intermediates, the photocatalytic degradation reaction of pyridazine which
has been accepted as the pollutant was modelled. Geometry optimizations of the reactants,
the product radicals, the pre-reactive and the transition state complexes were performed
for all the possible reaction paths. The Hartree-Fock calculations were carried
out on HF/6-31G* basis set. Based on the results of the quantum mechanical calculations,
the rate constants for all the possible reaction paths were calculated by means
of the Transition State Theory. The difference in the rates of reaction paths were
explained in terms of the presence of hydrogen bonds in the transition state complexes.
Full Text
Comparison of corrosion resistant behavior of Zirconium
and Tin based thin films on steel in 3.5% NaCl
Patel Niketan S.
The corrosion behavior of steel coated with Zr-N and
Ti-N films of varying thickness 1.5µ, 2µ, 2.5µ, 3µ and 4µ, deposited by cathode
arc evaporation PVD technique has been studied by potentiodynamic corrosion test
using 3.5 % NaCl solution. The electrochemical results obtained have been correlated
to structural defects studied by scanning electron microscopy. The phase analysis
of coating was carried out using XRD. The results of both Zr-N and Ti-N films has
been compared and reported. The results clearly indicated that both types of coatings
provide sufficient corrosion protection and in both cases corrosion resistance is
higher for coating of 3.0μ and 4.0μ thickness compared to the less thick 1.5μ and
2.0μ.
Full Text
Studies of DeNOx catalytic activity over some transition
metal oxide catalysts
Sakhre D. K., Sinha S. L. and Singh S. P.
NOx pollution due to increased motor vehicle use in urban
cities of India is today’s major environmental concern. Catalytic converters with
noble metal catalyst are common for petrol driven vehicles for reducing CO, HC and
NOx; but for Diesel driven vehicles and especially for NOx removal, catalytic converters
are not common. There are several techniques to control NOx emissions from diesel
exhaust, but After Treatment Technique has better advantages and more convenient.
To study the SCR (Selective Catalytic Reduction ) of NO (Nitric Oxide) by transition
metal catalysts; a series of catalyst of 2%, 5% and 8% wt% loading of Silver, Iron,
Chromium and Vanadium over γ-alumina support have been prepared, characterized and
tested in a stream of synthetic diesel exhaust gas which contains propane as reducing
agent. The catalysts have been characterized by BET surface area, pore volume and
XRD techniques. The catalytic activity has been tested between 1000-500oC reaction
temperatures and GHSV 6,000 h-1 to 18,000 h-1. It was found that 5% Silver catalyst
has given maximum 43% and 5% Iron catalyst has given maximum 39% NO conversion between
2000-4000C reaction temp- eratures. The study suggests that low cost silver and
iron based transition metal oxide catalysts can be used for removal of NOx pollution
from diesel exhaust gas.
Full Text
Correlation between Soil Physico-chemical Properties
and Heavy Metals Contents in Farmland around Scale Pig Farms, Nanchang City
Zhang Qiugen
The farmland soils surrounding scale pig farms in Nanchang
were sampled and the content of soil heavy metals and its physical and chemical
properties were measured. The Pearson Correlations between the content of heavy
metals and soil physicochemical property were analyzed through SPSS 18. The farmland
soil was generally acidic; the content of soil organic matter was above the third
grade; the content of available nitrogen was between the grades fifth and sixth
and the content of available phosphorus was classified as the rich grade. The farmland
soils surrounding scale pig farms were suitable for crop growing. The average content
of As, Cr, Cu and Zn was within the standard while Cd, Ni and Pb was out of the
standard. The competitive pollution index was greater than 1 which showed that the
farmland soils were in slightly polluted grade. Soil available nitrogen, available
phosphorus and soil oxidation-reduction potential were negatively correlated while
soil available nitrogen and available phosphorus were positively correlated. The
correlation among heavy metals As, Cd, Pb, Cu and Zn was highly significant or significant,
but the correlation among Cr, Ni and other heavy metals was not relevant. The available
phosphorus and oxidation-reduction potentials have an obvious influence on the distribution
of heavy metals. The available nitrogen has a non-significant influence on the distribution
of heavy metals while the soil water content, pH and soil organic have no influence
on the distribution of heavy metals.
Full Text
Adsorptive capacity of thermally treated clay from
northwest Algeria
Benhebal Hadj, Kadi Samir and Chaib Messaoud
The present investigation assessed the effect of the
heat treatment of a clay material on the adsorption of phenol from aqueous solution.
The natural material used is a clay mixture composed mostly of kaolinite and illite
and which has been heat-treated at 500, 650 and 800°C. The raw and heated clay was
subjected to different techniques of characterization as X-ray diffraction, Scanning
Electron Microscopy (SEM), Thermal analysis (TGA) and Specific Surface Area (BET).
Results obtained at different temperatures and concentrations of phenol show the
efficiency of heat treatment on the sorption capacity of adsorbent materials.
Full Text
Greener Synthetic Route to Some 2,5-Disubstituted-1,3,4-Oxadiazoles:
An Efficient, Rapid and Solid Phase Approach
Kumar Mohit, Kumar Vinod and Kumar Sunil
Today, use of greener approaches in the field of chemical
synthesis by inventing novel, environmentally and ecologically benign reaction conditions
has become an efficient alternative that can eradicate future problems in the chemicals
production. Herein, we report a green, rapid, efficient and solid phase synthesis
of 2,5-disubstituted-1,3,4-oxadiazoles in which various benzoyl hydrazones were
ground with diacetoxyiodobenzene under environmental friendly conditions. All compounds
were obtained in excellent yields and characterized on the basis of their melting
points, IR and 1H NMR spectral data.
Full Text
Adsorption of methylene blue dye on surface modified
Activated carbon
Takute Sapana, Singh Shripal and Yenkie M. K. N.
In present work adsorption studies of methylene blue
dye on commercially available activated carbons Filtrasorb-400 (F400) and Hydraffin
UV 43 were studied. The surfaces of Activated carbons were modified using sodium
dodecyl sulphate. The modified activated carbons were characterised for proximate
and ultimate analysis, iodine number, N2-BET surface area and pore volume. The adsorption
studies on different temperatures: 25,30 35,40,45 and 500C, pH: 3, 5, 6, 7, 8, 9,
10 and 11 adsorption doses of carbon 0.001, 0.005, 0.01, 0.015, 0.020, 0.025 and
0.030mg in 50ml MB solution were studied. Adsorption results show that percent removal
of methylene blue increases with the increase in temperature, pH and adsorbate dose
in the present study. The data were analyzed using Langmuir and Freundlich adsorption
isotherms. It has been observed that data was best fitted in Langmuir adsorption
model. The adsorption potential of modified and unmodified activated carbon for
the removal of methylene blue from aqueous solution was investigated and it was
observed that modified activated carbon has better adsorption capacity than unmodified
activated carbon.
Full Text
Solvent free synthesis, characterization and DNA photocleavage
study of some first transition series metal complexes of cyanoacetohydrazone Schiff’s
bases
Pal R., Kumar V., Gupta A. K., Beniwal V. and Gupta G. K.
The solvent free synthesis of metal complexes of two
tridentate Schiff’s bases, Salicylidene-N-cyanoacetohydrazone (CNL1) and 2-Hydroxy-l-benzilidene-N-cyanoacetohydrazone
(CNL2) with Co(II), Ni(II), Cu(II), Zn(II) has been achieved successfully under
mild reaction conditions. Among synthesized compounds tested for their DNA photocleavage
potential using plasmid DNA, metal complexes were found more potent as compared
to ligand under the identical experimental conditions.
Full Text
Structure Reactivity of Oxidation of Unsaturated Alcohols
by Quinaldinium Chlorochromate
Sekar K. G. and Palanivel V.
The kinetics of oxidation of unsaturated alcohols (Allyl
alcohol, Crotyl alcohol, Cinnamyl alcohol) by quinaldinium chlorochromate has been
studied in aqueous acid medium at 313 K. Unsaturated alcohols were converted to
the corresponding acrolein, crotonaldehyde and cinnamaldehyde. The order with respect
to oxidant and hydrogen ion concentration is found to be one and fractional with
respect to substrate. The decrease in dielectric constant of the medium increases
the rate of the reaction. Increase in ionic strength by the addition of sodium perchlorate
has no effect on the rate constant. There is no polymerization with acrylonitrile.
The reaction has been conducted at four different temperatures and activation parameters
were calculated. From the observed kinetic results, a suitable mechanism consistent
with rate law has been proposed. The relative reactivity order was found to be Cinnamyl
alcohol > Crotyl alcohol > Allyl alcohol.
Full Text
Preparation of collagen-elastin hydrolysates from
cattle tendons: Preparation conditions
Mokrejs P., Janacova D., Svoboda P. and Cermak R.
This study deals with preparing collagen-elastin hydrolysates
from cattle tendons through a 3-stage process. In the 1st stage, tendons are processed
in an acidic, neutral or alkaline environment which produces their swelling. In
the 2nd stage, a suitable proteolytic enzyme acts in neutral environment which leads
to disrupt bonding interactions of collagen and elastin. In the 3rd stage, hydrolysate
is extracted at elevated temperature from material so prepared. Variables under
study were the environment in 1st stage processing (pH 4-11), duration (2-14 min)
and temperature (60-100 oC) in 3rd stage processing on process efficiency (hydrolysate
yield). Tests are planned and evaluated by the method of statistic factor experiments.
Maximum process efficiency (76 %) was found with tendons treated in an alkaline
environment. Prepared hydrolysates of collagen-elastin type, light-yellow powder,
may be employed in cosmetics or the foodstuffs industry.
Full Text
Influence of Centella Asiatica Leaves Extracts on
Corrosion Inhibition of Aluminium in Alkaline Solution
Lakshmi Prabha K. and Rajam Shameela
The effect of centella asiatica leaves (CAL) extract
on the corrosion inhibition of aluminium in 1N NaOH solution was studied using chemical
and electrochemical techniques. It was found that the inhibition efficiency increased
with the increase in the concentration of centella asiatica extract upto 1000 ppm.
Beyond this concentration there is no improvement in the inhibition efficiency.
The potentiodynamic polarization studies reveal that CAL extract acts as a mixed
type inhibitor. Adsorption of CAL extract on aluminium surface follows Langmuir
adsorption isotherm. A good agreement was observed between the results obtained
in non-electrochemical and electrochemical methods. The protective film formed on
the surface of aluminium was confirmed by Scanning Electron Microscope studies.
Full Text
Effect of Heavy Metals and Organic Pollutants on Antioxidant
Enzyme Activities in zebra fish by polyacrylamide Gel electrophoresis
Zhang Qiugen, Chen Suhua and Deng Fang
The potential utility of antioxidant enzyme activity
was evaluated as indicators of exposure to heavy metals and organic pollutants in
aquatic organisms. The effect of heavy metals and organic pollutants on antioxidant
enzyme activity of zebrafishzebra fish was studied. The trends of superoxide dismutase
(SOD) and catafase (CAT) activity in zebrafishzebra fish under after exposure to
heavy metals and organic pollutants for different time were analyzed by polyacrylamide
gel electrophoresis (PAGE) technique. The brightness of bands in the polyacrylamide
gel electrophoresis is almost consistent with the trends of antioxidant enzymes
(SOD and CAT) activity in zebrafishzebra fish, namely, the greater was brightness
of the bands was, the stronger was activity of SOD and CAT was, indicating PAGE
is an effective technique to evaluate the antioxidant enzyme activity. Moreover,
the results showed that the exposure time and concentrations of pollutants have
a great effect on the SOD and CAT activity in zebrafishzebra fish, . and the dDose-response
relationship between SOD/CAT activity and heavy metals or organic pollutants was
established.
Full Text
Application of carboxylic acids in photo-Fenton-like
systems for the removal of contaminants
Danna Zhou, Wenyu Huang and Dandan Xu
Advanced Oxidation Processes (AOPs) using hydroxyl radical
(HO•) have been successfully applied in the oxidative removal of organic pollutants
in wastewater. Fenton or Fenton-like systems, which are AOPs that employ hydrogen
peroxide (H2O2) and iron species [Fe(II) or Fe(III)] under acidic conditions (pH
3.0), have been extensively studied over the last two decades. However, such systems
have low efficiency at neutral pH mainly because of the presence of insoluble forms
of Fe(III) or Fe(II) under this condition. These species lead to very low yield
of HO• in the presence of H2O2. Carboxylic acids can complex with and stabilize
Fe(III) at higher pH. Fe(III)-carboxylate complexes exhibit higher photoreactivity
than that of the Fe(III)-OH complex. In this paper, we review the application of
carboxylic acids in photo-Fenton-like systems for the removal of contaminants.
Full Text